Feb. 01, 2006 By Rick Sieman

If you choose to email a question to this forum, then you must conduct yourself accordingly. Therefore, the following rules are in order:

1. Do not write your email to me IN CAPS. If you do so, I will print out your question and do terrible things to it.

2. Do not request a personal email response. Since I get thousands of questions each month, trying to answer them all would cut deeply into my leisure time, which I value more than your current state of confusion.

3. Try to spell at least in a semi-correct fashion. If you choose to mangle the English language, expect no mercy from this quarter. You might be mocked severely.

4. Do not ask for me to send you copies of my many manuals and literature. I am not in the library business, not do I want to spend the bulk of my day at the copy machine just because you're too lazy to ask your dealer, or look around a bit.

5. Don't bother me with truly stupid questions, like how to get 50 more horsepower for a buck and a half.

6. Now that you know the rules, think carefully and have at it!


Hey Super Hunky,

I have been waiting for a reason to ask you a question for a long time, and now I have one. The deal is: I want to install a pig of an XL 175 into a '73 Bultaco Pursang. I want to know what the complications of putting a Japanese engine into a Spanish bike are; will the bike and engine fight every time I reach for the go knob, or will the wheel fight the engine every time I push on the stop peg?

My dad seems to think that they won't fight, but I know how Bultacos fight you when they have their own power plants, so what will happen if it has the complete wrong engine?

Your advice is needed very much, if only to settle this argument, but no matter what, we will still do the swap.

Hayden "I ride a Bultaco flattracker" Campbell


Young man, you and your Dad are sorely tempting the fates with this strange transplant. If you complete it, chances are that Franco will start spinning in his grave like a bad axle on a Yugo.

I assume up front that you know the XL 175 engine was a real dog, even when it was brand new. If memory serves correct, I don't recall it registering anything at all on the dyno.

You will spend a great deal of time drafting butterflies with this motor stuffed into that noble Spanish chassis. The ghost of Senor Bulto will haunt you. Gilbert Roland will probably slip on a Zorro mask, clench a rose stem in his teeth, and stomp a mud hole in you and then stomp it dry.

You are playing with fire, young man. I beseech you to cease this folly and instead take up something much more rewarding, like breeding leeches.


Hello Rick Sieman,

I've just discovered your email here in Sao Paulo in sunny Brazil. The reasons I write you are some:

1. I've been reading your mag-articles for quite some 10 years now, they're interesting

2. As a former enduro champion in the state of Sao Paulo ('87, '89 and '91), I'm frustrated having no time to ride lately, so I do some two trails per month. Thus, there comes need for some more equipment to make up for less guts and technique.

I've got some questions concerning my well kept '95 XR 600 (USA 49 state version).

How can I get power cheaply?

See, imported parts are quite deep reaching into our Brazilian pockets, due to high import taxes (circa 100%).

So what have I done to the bike already?

To the motor: I've got good carbureting experience, because our gas is like Mexico's, and the tuner am I myself. So I have installed a Twin Air filter, removed the end cap of the original silencer and carbureted it. The main jet grew a lot (don't know the number, but it's 1.55mm thick), the needle only one position richer and so is the pilot. The bike got a LOT better midrange and top end, since the air intake and exhaust volume increased.

The detonation when very hot, though, was only removable by enrichening it a bit too much on the main jet.

I use an NGK DP8EA9 spark plug, which is close to the original ND and not hot.

So the acceleration could get better if I could eliminate the detonation and being able to run a bit leaner on midrange and top. As of now it is a bit sluggish; a bit too rich.

Should I tear the top end apart and do a good porting and combustion chamber job? Would this give good power increase? I do not want to spend money in new pistons, or valves, since the motor runs smooth and is in good condition.

We also don't have good octane boosters available for reasonable price. Any clue?

By the way, did you know that Rodney Smith turned to Enduro-liker here in Brazil, where he lived for some years? We crossed lines some times in the Sao Paulo trails back then.

I thank you in advance for some return, even if you don't want to bother answering the far-away south-american-portuguese-speaking guy.

Best regards, keep up the momentum,

Ralf "trail" Theil


Ralf, the key to making a 600 XR perform at its best is to give it lots of air. You went in the right direction with the filter, but I would also consider opening up the airbox even more with tapered slots on the sides to let air in and keep water out.

Secondly, you can make your own octane booster simply by adding the chemical toululene to your gas. It's the base for most octane boosters sold here in the states.

Once you get sufficient octane in your fuel to prevent pinging and detonation, you can then lean out the carb once again, and then advance the ignition timing. Be careful when you advance the timing and do it in small increments. The XR 600 is very sensitive to small changes in the ignition timing.

Don't waste your time or money on porting or headwork. Consider a less-restrictive silencer. It doesn't have to be from a Honda. Just make sure the bore is the same.

Good luck and let me know if this helped.


I'm 50 years old and riding an '86 YZ-490. I like the bike because of it's excess power and simplicity, but it's famous for being a blubbering, bucking, brute of a machine that will eat you alive if you nod even for a second.

I want to keep riding off and on for the next 10 years with my son. I'm thinkin' an XR-400 will treat me with more respect, but they're heavy also. Then there's the venerable KDX.

If you were fat, bald and old, but wanted to cover every trail out there for as long as you could still lift your leg over a dirt bike, what would you choose?


Rick Oringer
Los Osos, CA.


Well, my friend ... I am old and fat, but thankfully not bald, and I think the most mellow and fun bike around is the KDX 200. Sneak a ride on one - even a five or six year old bike - and you'll see what I mean.

1989 KX 125

Hey Super Hunky,

I have a 1989 KX 125 and I am pretty much clueless when it comes to mechanics. Here's my question. If I take the bike for a short ride, say 10-15 minutes, the bike fouls a plug the next time I try to start it. But if I take it for a ride for one hour or more, the bike doesn't have a problem. I mix the gas at a ratio of 40:1 and I live in New Jersey, if that helps you in any way.



What you are experiencing is a simple case of too-rich on the jetting. During a short ride, the plug tip does not get hot enough to burn off the deposits that accumulate there. During a longer ride, the plug literally "cleans" itself.

Rather than go through a long and involved jetting ritual, consider changing your premix ratio to 32:1 and going to a slightly hotter plug. By increasing the ratio of oil to gas, you are effectively leaning out the jetting. Give this a try and make sure you start with a fresh plug.


First off, I have to say I laugh my ass off when I read your comebacks to the goofs that can't spell, ask stupid questions and ride 80's.

I've been riding for about eight years. I started on an '84 CR125 when I was 15, moved up in about a year to an '84 CR250, then to a '90 KTM540. Now I'm 22 and own a '92 XR 600.

I think I'm finally nearing the point of having everything I need to start racing, but I wonder how competitive I'd really be, and what the best/cheapest way to get into racing is. My time and money are limited, as I'm currently attending Arizona State University.

The 600 has a 4.7 gal. IMS tank. I've beefed up the suspension with the stiffest springs I could find, and the only motor mod I've made is the addition of an FMF MegaMax II. The bike is fast, there is no question about that.

I have the problem of being a bit on the large side. I'm 275 lbs. without gear on, but I don't get very tired riding the bike even for extended periods of time, like going through at least an entire tank of gas (150 miles). I can lift the 600 to chest level (I made it a goal after seeing the picture of Scott Summers doing it), and can get the thing through knee high sand whoops in forth or fifth gear with no problem. I've never raced before, but it's something I've always wanted to do. Do you have any advice for me, or should I just jump right in?

Thanks in advance for any info.
Allen Kelley


Absolutely, Allen. The fact that you're big and strong makes that heavy bike just about right for you. About the only thing you might consider is a quality shock. While it's one thing to get the spring rates right for your weight and aggressive style, it's another thing to get the damping right and to have it last.

The one flaw I've found with XR600s over the years (aside from the odd hard starting glitch when hot), is that the rear end hops badly when the shock gets hot and hits a square bump.


OK. My father recently surprised me by buying me a Yamaha 465 dirt bike. OK. The thing is pretty tore up, but he invested some money in it and now it runs. The problem is the guy at the bike shop said that the bike would be way too powerful for me, since the closest I've ever come to a dirt bike is a moped.

Also he said that some one added on the kick stand (I don't think this is true, since I looked in the manual). What do you think?

Clifford Brown


OK, Now listen up, OK? The guy at the shop probably gave you the best advice you'll ever get, OK? The 465 was a brute when it was first built, and the passing of time has not made it any less of a brute, OK? If you have little or no riding skills, chances are the 465 will stuff your head into the ground half way to China and you'll never know what hit you, OK?

Use that kickstand to park this bike while you learn on something a whole lot more mellow, OK?


I just bought a used 1982 Yamaha YZ 125 dirt bike about 3 weeks ago and its been riding fine in my back yard, but once I put it in my van and drive it to ride, I can't get it started. I just want to know why it wont start and why it keeps back firing when I try to start it up?



Could it be that your van is haunted? Could you be riding in the Twilight Zone? Nope. Then answer is much less interesting.

Here's what's happening. When you put the bike in the back of the van and haul it out to your riding area, the bike jiggles up and down. Your float level is probably set a bit too high, it the float needle seat is worn, and the jiggling lets gas slop into the motor. Then when you try to start the bike, you're trying to boot it up with a whole lot of extra gas in the bottom end.

The cure? Drain your float bowl and make sure your gas tap is shut off when you transport the bike.


Hey Rick,

I recently bought a new WR 400 and I need some guidance in setting up the suspension, ex. spring pre-load, checking spring rate, shock comp. and rebound etc. I ride mainly enduro style. I'm 6-1, 1951bs. and am an intermediate rider. Nothing in the manual helped me in determining how to figure out how to setup my suspension, so anything would be appreciated.

Jim Smetona


Jim, start out by setting the sag at 100 millimeters. You do this by measuring two points on the rear end of the bike with the bike unloaded. Then sit on the bike with your feet on the pegs, and measure the distance again. It makes the job easier when you have a friend help you do this. When you have about 100 mms of sag, you're in the ball park. After that, you can then play around with the compression and rebound clickers.



Recently I discovered my childhood minibike in the garage at the folks. It is a Honda Elsinore MR 50. It, like you, is old and crusty! Just kiddin!

I have been unsuccessful in locating a manual so the hubby can get it working for our girls. (yes, girls).. Can you help us out?

Thanks much, and have a great day!
The Martins


Since I work for a magazine called Old Bike Journal, I can safely tell you that you can find just about any manual for any bike in their classified section. A one year subscription is $19.97 for 12 issues, and a single copy costs $3.99 on the stands.

The address is Old Bike Journal
Tam Communications
1010 Summer St.
Stamford, CT 06905
(203) 425-8777

You could also find a manual for your bike from Clymer or Chilton. Check with most any savvy Honda dealer and they'll probably be able to order it for you. Good luck and have fun.



I Have A 1974 MAICO 250. Could You Tell Me How Many Drive Plates And How Many Driven Plates And Clutch Springs I Should Have On This Bike? I Bought This Bike About 7 Years Ago For $75.00 And Now It's Time To Make It Rideable. It Runs Good, But The Clutch Is All Rigged Up. It Has An Alloy Tank And Forward Mounted Shocks. (Is That What's Called A Wheelsmith Conversion?) Should The Frame Be Silver? Any Help Would Be Appreciated!



Chris, while I have received letters written in all caps, or in all lower case, never before have I received an email with every word capitalized! I am stunned! But please ... don't do it again.

Now, since you asked a reasonable question, here's your answer:

A normal Maico clutch will have six drive and six driven plates.

The clutch spring stack should be five sets of four, set-up like this:

(( )) (( )) (( )) (( )) (( ))

The frame should, indeed, be silver.

You might have a l975 swingarm or a conversion. There's no way to tell without seeing it.



Hope you're doing well down in the "land of the free, home of the oppressed". :)

One quick question. How many letters like the ones from Tom Torresdal (MORE THAN CLUTCH TROUBLE), Joel (WHY 12YEAR-OLDS CAN'T VOTE! ), John (are DBs dangerous), and Steve (IN SEARCH OF THE ELUSIVE POWERBAND) do you get each month?

Are these from someone just screwing around, or do they really come from real "people?" If so, what does that say about your readership? ;-)

Tim - living the American "dream"


It seems like we get about 20 intensely stupid emails each month. When you consider that thousands of emails are received, that's not a bad ratio. Actually, those pinhead letters make for a few good laughs.

The next letter is typical. Enjoy.


i do not understand why you treet younger riders like garbage because of typos and other things ....... these kids are writing to you for help and you insult them!!!!!! you may know your dirtbikes but in my eyes you are a peice of garbage and shouldnt be allowed to even ride a bike

your a piece of sh*t


Ahhh, here we have the perfect example of the Numbskull Factor in full force! You will note, dear readers, that I have left the mis-spellings intact, so you can marvel at the shortcomings of the educational system.

Kevin, Kevin, Kevin ... take note. In your last sentence, you said: "your a piece of sh*t"

That should be: "You're a piece of sh*t."

Please notice that "you're" is a contraction of "you are" while "your" is a possessive, meaning that you own it.

Now go stand in the corner for an hour with your finger up your nose, and repeat the phrase: "I am a bad boy!" several hundred times.

And Kevin? Don't email me again until you can spell at least as well as the average parrot.


Uh hi...

My moral dilemma is... I have a 1995 CR500 that has a Baja designs kit with the e-line coil and is street legal here in California. Well, I want to start doing those long dual sport rides, like the multi-day ones that do over 200 miles.

I've done a couple long street rides and I'm starting to wonder if I should sell it and get a 4-stroke? Do you think a 4-stroke would be better for me? I don't ride as much as I want to anymore, so I want the rides to count. I'm 28, married, two kids with a HUGE mortgage payment (I live in Pacifica. near San Fran).

I was thinking about just getting a bigger tank and maybe a Corbin seat to save my ass. Thanks much for your columns in DB that helped to form me into the HUMAN I is today!!

One more quick? Do those rubber mounted sprockets on the XRL's really save the transmission that much on the street?



Since a whole bunch of people are buying the new Yamaha four strokes, all of the sudden, you can find some very nice clean Honda XR 400s for sale at good prices. While the XR 400 is nowhere near as fast or good handling as the YZ 400, it's nonetheless a genuinely easy bike to ride at a brisk pace for a long way. The bike will not beat you up like your CR 500 on a long ride. If you made the CR street legal, the XR will be a snap.

Yes, those do help the trans life, but only if you ride the bike hard on the street. The best way to extend life in an XR is to change the oil frequently.



I am in the process of resurrecting dirt bikes for my kids. One is a 1981 Yamaha YZ 80 the other is a 1976 Yamaha YZ 175c. Is there an after market source of parts, such as reeds, ignition components and common replaceables?

Also, do you have any comments on the bikes I'm referring to?



You can get aftermarket reeds from Boyesen for darned near any bike ever built that used reeds. They advertise in many magazines. As far as ignition parts, you're stuck with stock.

Both bikes were solid, reliable fun machines.


Are You High?!?!?i? (on something)? I don't "Race", but I do play in the mud often.

The only blades I use are a stainless steel, or plastic blade, made by Flex-a-lite. They work great.

Maybe your views are warped. (after all you do drive F*rds and it is a cuss word all its own.) So what is wrong with flex fans, or do you mean flexible blades? When you get done scraping the resin out of your pipe and thinking about it. Get back to the world with the answer before re-lighting.

Gabriel Hall


For your needs (playing around), chances are almost anything would work. For the world of racing, where demands are high and failure of parts is unacceptable, flex fans have no place.

A flex fan, by its nature, flattens out as the speed increases, and probably saves you a small amount of power. It also sucks less air through the radiator than a standard non-flex steel fan.

It's not hard to make horsepower. It is hard to keep an engine cool at 120 degrees in the desert at full throttle up a sand wash. Also, when I used to run flex fans in my early days as a kid hot-rodder, I had more than a few crack and break off.

Why? Because they're made of thin metal (or plastic) that's constantly flexing, which leads to cracking and failure. Now go play in the mud and don't bother me any more with your druggie references.


Hi Rick,

I really enjoy older bikes and I currently have a 1980 Kawasaki KL 250A four-stroke. I haven't had it for very long, so I was wondering if you could tell me a few things about it. Also, I found a 1980 CR250 for sale and I am planning on buying it. Could you tell me a bit about this one, too?

Thanks a lot
Dan Randall


The KL is/was a nice trail bike made from very dated engine parts and is a bit on the slow side. Trying to get much in the way of ponies out of them cost a lot and was an exercise in futility.

The 1980 CR is very fast, but has poor shocks and forks.


Hi Rick

I'm really up against a wall and if there's anyone in this world who can help me by answering a few questions, it's gonna be you. Actually my questions are simple questions, like jetting, timings, restrictions so on and so forth on a WR400F. You must be wondering what's the problem then. OK, let me tell you my problems.

I don't live in the states; in fact it's not even anywhere near it. I am from Singapore (and I assume you know where the hell it is, 'coz we do have dirt bike magazines being sold here) and I just got myself a brand new 98 WR400F.

You might wonder why can't I seek help from my local mechanics. Well, all I can say is that they know nuts about this bike.

The only 4-strokes they know are KTMs and XRs. In fact, the WR400F only came out in Singapore early this year, and believe it or not, they are still selling the 98 model now! And to make matters worse, my WR400F is from Spain, and I know they can't speak English.

A bit about my bike. It is stone stock. The only think I changed, which may affect the performance, is the sprockets. It now runs 14/45 and stock was 14/50. It was way too much of a motocrosser with the stock gearing. I do simple trails during the weekends and most of the time, the bike will be on the streets.

The header pipe is the same stainless steel pipe that you are familiar with, but the muffler is a one piece junk made of iron (I think)with just a tiny hole at the back of it. I can't remove the baffle 'coz there ain't even an end cap to start with. The pipe is somewhat similar to the XR600 and the Australian WR400F, minus the spout.

My airbox lid has two rectangular holes. It comes with full lighting, including turning lights. That's just about all that I can describe about my bike, as the rest is the same as those that are selling elsewhere.

Here comes the questions: Does my carb have the pin that restrict full throttle? If yes, should I grind it down to 12 mm or 16 mm? What is the best way to optimize my WR400F without changing the pipe?

I would love to change the pipe, but the traffic laws here are the strictest in the world and wouldn't want to get caught just after a day's riding and pay a US $300 fine. Is it advisable to change to YZ400's timing?

Also, when I pull the throttle hard and close it subsequently (without clutching in) in 2nd or 3rd gear, there would be a very loud explosion-like sound from the exhaust. What the hell is that, man?

I am running 98 octane unleaded gas. Will removing the airbox lid and changing to a higher airflow filter make any difference, since won't be changing the exhaust? I heard there is another oil filter other than the one at the right side of the bike. Is that true? If it is, how can I clean it and how often?

I guess that's just it for now. I really do need the answers to these questions and hope that you'll understand why, 'coz I'm stuck in a land where all the mechanics know nuts about WR400F.

If it's any consolation, at least my spelling won't make you go to the fridge for a can of beer to calm down.

Thanking you in advance


You CAN change your performance and timing to that of the YZ 400 without spending any money on parts. Acquire a YZ/WR manual and simply alter the settings on the cam position and timing to that of the MX version.

But, is that what you really want for a bike used primarily on the street? You should limit your modifications to making the bike breathe better (open up that air box and start by tossing that lid), and see if you can slip on a Honda muffler. They're very efficient, albeit a bit on the heavy side.


I recently picked up some old Dirt Bike mags (May 72, Dec 73, Feb 74). The two earlier mags tested Yamaha's 72 DT2MX and 74 360MX respectively. Both tests complained that the forks were harsh. There was also a complaint with the 360's powerband (on/off) and that it ought to have made more tractable power.

I have both a DT2MX and a 73 250MX. In last month's "Don't Ask" you offered advice regarding these bikes. The author of the original inquiry had stated that he had a DT400 enduro. You know, that DT400 enduro motor makes the right kind of power.

My 73 has a 75 enduro motor (with the MX carb and pipe). It has an external flywheel magneto ignition and is extremely tractable in choppy modern bike conditions. That Dec 73 also has an article in which a MT250 bottom end was married with the rest of a CR250. Kinda the same deal.

I blew the Konis out on my 73 yesterday and ordered some Works Performance shocks today. Funny thing, the forks didn't seem bad at all yesterday. I stuck 5 weight in them and installed a Renthal vintage/desert bend bar last week. They'll be the weak link again once the WP shocks get on there.

In last months "Don't Ask" you also recommended swapping the stock forks with Cerianis, Betors, or the Italian "M" brand that I'll have to look up in the dictionary to figure out the correct spelling. Kinda surprised you didn't advise grafting a set of Maico forks as that was popular back when.

I had a 74 Ossa Phantom. I bought it new and had the rear end modified to accept lay down shocks. The Betor forks on that bike always felt way harsh to me, but I just figured that was right and I just must be a squid.

I'd had a 67 Greeves prior to that with Cerianis and a 19" front. Now those were good forks. The rest of that bike, well...

Anyway.... in that Feb 74 issue (gas filter shootout), you guys tested a fork kit made by No.1 products. It sold for a whopping $9.95 plus 50 cents postage and handling. The article was entitled "TRICK FORK KIT FOR UNDER TEN BUCKS, Make your Yammie forks better than Betor, by Rondo Talbot". I quote from the article "Fantastic. Absolutely fantastic. The ride was as soft as any set of Cerianis or Betors we have ever ridden... No impact came through the bars... the forks faithfully followed the bumps and undulations."

Do you remember that kit at all? I ask because the forks presently on my 72 have that kit in them (came from a 74 360 part bike). The 72 needs a top end, so I haven't run it other than around the block to see if it ran at all. I've been quoted $200 to revalve and rebuild the 73 forks, which is a reasonable cost when you consider how much being laid up in plaster runs these days.

Regardless, $200 is $200 and I'd rather not spend it if it's not going to buy much. Should I swap the kitted forks over to the 73, or go for the revalve?

Rod Simmons


Your idea of swapping enduro parts to an MX bike makes a lot of sense when you're talking about Yamahas. They have a tremendous part interchangeability factor within many groups of model years.

Once you get the Works shocks on the rear, you might find that the front end feels harsh. Good shocks tend to do that to poor forks.

The reason I did not recommend Maico forks instead of the others in the article, is that Maico forks are very desirable and pricey items.

Regarding the Number One Trickit. I was there when the kit was being prototyped. Designer Brian Fabre simply copied the Maico valving to fit any KYB fork. At that time, KYB came on Yamaha, Kawasaki and Suzuki, while Hondas used Showa forks, mostly because they owned about half of the company.

These kits worked and worked well. I would stick with them, rather than spending any large sums.



I have read your stuff forever and had no idea you were here. I just got into 4-wheeling recently as a supplement to my years of dirt bike riding, circa 1965 to present.

Well, I can tell you that if you endorse this place, then I trust em. Power lifters and off-roading rules. Ride on, Super Hunky. You kill me. I've always enjoyed a cold beer and an article that you've written.

Later bro
Gary Dudley
Ex-D-37 nobody. (but I do know some fast guys.)


Yeah, but I bet I know more slow guys than you do, Gary.


I would like to improve horse power for my Toyota 4-Runner without spending a whole lot of cash. What would you recommend?

No Name Given


Easy, No Name. Just unscrew the spark plugs and screw a 460 Ford back in them. Problem solved.


I need some info where I could find a Rotax 250cc engine. I've checked hundreds of junk yards and even got quoted a price of $700.00 for the electrical components I need. The motor is mounted on a home made 3-wheeler and is guaranteed to haul.



Easy one. Call up Tony Murphy at (661) 944-1642 and tell him Rick sent you. Tony is a former road racer/magazine type who has (literally) a barn full of Rotax parts.


Hi Rick,

I have a question about a friend's Yamaha XT600. He told me he had problems with the machine: it would only reach a maximum speed of about 20 mph.

Without trying the machine (I know, I should have done that first) I cleaned the carburetors and they, indeed, were filthy, but the problem was still there.

I tried the machine and something else is clearly wrong. The machine pulls like a horse to about 4000 RPM, but then it's dead. I noticed a lot of noise coming from the engine head, but not a noise like anything is broken.

It's more a noise as if there is a RPM limiter cutting down the ignition. Further inspection of the engine revealed that there is air coming from somewhere within the engine (it's leaking out the transmission part somewhere).

Do you have any idea where we have to search for the problem?

Thanks in advance,
Ron Mevissen
The Netherlands


Whoa! This one sounds strange. My first impressions are that you should suspect a massive air leak. In fact, it almost sounds like the drain plug has fallen out of the engine.

Your problem could be something as simple as a collapsing air boot. When the throttle is whacked open, the suction pulls the walls on the air boot in, restricting revving.

It could also be a badly clogged filter doing the same thing. You might also check to see if there's excess slack in the throttle cable. Something as simple as that could cause the rpm barrier you described. Start there and let me know if any of these things help.

WR 1993 500 YAMAHA

Hi Rick,

I recently found a cream puff bike. Been stored for year and a half, only ridden 3 times, not a scratch on it, the tires weren't even worn out!

Question? The factory jetting was never changed and oil dripped out of the silencer at mid-range throttle. I leaned out the needle all the way. Still it has no bottom end or mid-range power. Runs great on the top end, though. What's my next option?

Jeff Hassebroek.
Sandy, Or.


Your next option is to have a shop check the crank seals. Chances are they are hardened and leaking, which would make the bike run (and drip) just like you described it.


Dear Ricky,

I am interested in purchasing a used dirt bike. I am a 14 year-old beginner who is 5'6" and 115 pounds. I have saved around $700 to spend on a reliable bike. I plan to ride trails mostly, eventually with a few jumps.

I have seen several interesting deals on '90-92 RT180's. What do you think I should look for/expect to get?



Your choice is right on for a beginner's bike that's reliable, light, fun to ride and easy to work on. Look no further, Joshie.


Mr. Sieman:

I'd like to thank you for all the humorous and serious articles over the years. I got into motorcycles in the early '70s when I got a job at a shop after school. If I'm not mistaken, I started to read dirt bike magazines about then, as well.

I must mention one thing in passing. I read a note sometime back in one of the off road mags, can't recall which --probably Off Road. It mentioned a book you penned, titled "Monkey Butt!" Coincidentally, the picture on the cover brought back some memories. I read that plug, I think on the toilet before I showered. I got into the shower and about two minutes later it became clear. Big, red, puffy monkey butt!

I laughed so hard and so loud in the shower I thought I'd die. I worked on a fire crew called the Sawtooth Hotshots at that time, and I used the term freely; however, you always got credit for the term.

Tripped over your column searching for a set of trac bars for my truck. I'll put it in my favorites and savor it when I can.

Thanks again,
Dan A. Taylor
Spokane, WA


I hope a simple and sincere thanks will suffice in exchange for the kind words.


Hey Rick,

I'm a young Australian guy who has just brought his first bike. This is probably a goofball question, as I haven't owned a bike before. Today was my first go on the bike (a Suzuki TS 185), so I loaded it in to my van and headed of to my boss's house in the bush.

After unloading the bike at the bottom of his driveway (a 2 km 4wd track, very steep and rough in places) I started up his drive.

I made it two thirds of the way up the worst hill, but had to stop, as it was very slippery and the ass end of the bike was going everywhere. When I got my act together and tried to start off again, I had difficulty starting on the hill, and I think I stuffed the clutch, as I can let it out and there is nothing.

When I got home, I drained the oil from the gear box, took of the case, and every thing seemed to be in order. I presume that my bike has a wet clutch, so I don't think I could have worn it out.

Is it possible that I just need to replace the gearbox oil to fix this? If the oil was stuffed, would the clutch have gone on me so suddenly? Does clutch oil wear out like that?

Would riding the clutch badly about five times cause this sort of a problem? (Maybe it was already half stuffed)

I have checked the adjustment of the clutch and it seems fine. Sorry to bother you with such a lame question; it's just that I've spent so much on the bike and all the accessories to go with it, that I can't afford to take it to someone to fix it, and I would really like to learn how to do this kind of thing myself.

I've spent all afternoon, but I can't seem to find the problem.

Thanks ever so much,
David Parums.


Welcome to the cold, hard, cruel world of buying an old used bike, David. Since the bike already had a lot time on it, all it took was a few brutal slippos on the clutch to smoke it.

You'll have to take the clutch apart and inspect the plates. First off, buy a decent manual to get the wear limits on the plates. Then check the plates for flatness by placing them on a piece of glass. If they're warped, they must be replaced.

You can do the work yourself with a minimum of hand tools and some patience. But you will need that manual. Check with your local Suzy dealer and he can order one for you for probably under 20 bucks. When you're done with the job, put some fresh oil in

it, and change it regularly. And don't hammer this clutch, as it's not a particularly strong one.



First, the disclaimer: I bought my 84 SP600 before I knew crap about bikes, and knowing what I know now, I would have picked up an XR600R instead. That being said, I still like the damn thing, but I have a problem.

I was in a wreck a while back and bent both front forks (hit a car) and I cannot find replacements for less than about $600. I've been told they only made this bike one year (for good reason, I know you would say) and it is difficult to get parts for them other than direct from Suzuki.

I would like to know what other forks would swap out with these (if any) and where a good place is to find replacement parts (turn signals, plastic, etc.). Thanks in advance for the help. Great site!

Denver, CO


Actually, they made the SP 600 for several years. If nothing else, it had a reliable engine. You could run these things hard and they would stay alive, even with minimal service.

That said, the bike is a real porker, very heavy and stuck with crude suspension. The answer to your problem is dead-nuts simple. Almost any Kayaba (KYB) for assembly will slide right into your existing triple clamps. During that time frame, Suzuki, Yamaha and Kawasaki used KYB forks, while Honda stayed wit Showa forks.

Scrounge around most any bike boneyard with a tape measure in your pocket and find a complete set of forks that will slide into your steering head, or just a complete set of tubes that will slip into your existing triple clamps. Problem solved.


Dear Sir Rick

I hope that you can make some suggestion, well I am sure that you will. But any how this is my problem. I own a YZ490 (model T 490 to those who ride with me). I'm sure owning it is not a crime? I hope. Any ways. the bike runs fairly well and has fair amount of power; a bit crappy that it is a four-speed, but I sort of fixed that by running 16/43 final gearing,

I was wondering if you could make any suggestion related to jetting this beast.

I've also heard mention of some sort of cylinder head modification that can be done to

help prevent pinging and the like, but cannot find out what the exact mod is. Whether it be skimming or whatever.

I recently had the cylinder rebored and had a 1.5 oversized piston installed. Which resulted in upping the compression quite bit, probably cause the old piston was a tad worn (add desired F type word)

Any suggestions are greatly appreciated.

Your humble subject


Sit down and grab a cold one, Andrew. The 490 Yamaha was a pig when new, and the passing of time did not reduce the "oink" factor one bit. It pinged and detonated badly with the stock compression (unless jetted on the fat side) and will only be worse with increased compression.

Lots of people tried to make the bike better when it was new, and all of the efforts were marginal, at best. About the only thing you can do is double up on the head gaskets to lower the compression, and jet the thing in some sort of compromise. No matter what you do, the bike is a loser. Sorry, but them be the facts.


I recently purchased an old 71 Honda SL125 for $50.00. After minor work, it ran good and I really loved the bike. I changed the oil and it seized up. After putting heavier oil in it, I got it turning over, but there is no compression. What do you think happened my bike?

Nascar 135


Nas, old buddy, you simply ran this old bike too hard and smoked the top end. If it stuck, you'll have to yank the top end, probably bore it and install a fresh piston and rings.

1984 HONDA CR 500

Hello Super Hunky

I have a Honda CR 500, 1984. I was wondering why did the bike get such a bad rap? Motocross Action said that the bike pinged and a quick and popular fix was to run two head gaskets and put a 314 jet needle in the carb. I did this and the bike runs clear and smooth, faster them my friends CR 1983 480 .

The only way to fix the suspension (in my eyes) was to put on the "88" Showa cartridge fork with a Scott Summer fork brace. In the rear, I installed an Ohlins shock. I like my bike a lot; even Motocross Action admits that the bike got a bad rap (I have the articles)and they said (two years later) that the bike was a good bike after all. (I have the proof).

Aaron Flores

P.S. I use to watch you race at Saddleback in the early 70's. My brother use to race there, too. He still talks about the good ole days when real men used to race.


Aaron, while it's nice to see that you have made your bike work a whole lot better, I fail to see how you can justify spending such large amounts of money on such an old bike. The Ohlins shock alone is worth just about what the bike is worth on the used bike market.

I gave this bike a bad write up back then because it required so much work and money to make it work half decent. At that time, there were other open class bikes available that worked just fine, in stock trim.

If you spend enough time and money, you can make a phone booth go fast and handle. But that doesn't mean it makes sense. Anyway, have fun.



I am looking for a replacement chain for my 1975 Kawasaki F7 trail and road bike. A while ago I was riding down the road, when the chain came off and got stuck in the sprocket and got all bent real bad. So I went to the Kawasaki dealership to see if I could get a chain, but with my luck, the chain had been discontinued.

So I was wondering where I could get a chain? Or if I could get a motorcycle chain and shorten it, or do the same to a dirt bike chain? Any help would be greatly appreciated.



I don't know what kind of a dealer you talked to, but you should have absolutely no problem whatsoever finding a chain for this bike. You simply buy the same size chain it came with - in your case probably a 520 - and cut it to the correct length. Your bike might have come with one of those stupid linkless chains. Any normal chain will work on any normal bike. Got it?


I want to get a bike for my just-turned 11 year-old son who is short in stature and has never ridden. I had him sit on an XR 70 and the balls of his feet just touch the ground. Many are recommending that we should avoid a 4-stroke because he'll be bored with it in no time.

Some say go to a 2-stroke, and others say just see if he can pick up an XR 80, as that will have plenty of power for him for several more years. I'd welcome your advice and any recommendations on what models might be appropriate (I have no qualms about him learning to shift.).

Mark Garetz


You're on the right track with the XR 80. Not only is it a fun bike to ride with plenty of friendly power, when he does get bigger, the bike will be easy to sell, and holds its value amazingly well.


I am looking at a 87 YZ 125. It needs a front tire and has a leaky gas tank, and the asking price is $500. Is this a good bike by today's standards? Or should I spend some more money to get into the mid 90's? Any info on the bike would be appreciated.

Jim Frinton


You're looking at a 13 year-old 125 MX bike. Under the best of conditions, it's going to be tired. The fact that it has a worn-out front tire and a leaky gas tank tells me that it was more than likely abused under the former owner. I'd stay away from this bike and look for something about five years newer in the thousand dollar range.


I have been a fan of your writing for years. In fact, since I was 13 and bought my first dirt bike. It was an AT-1. I wanted a 1974 Elsinore, but was talked out of it by my grandpa, because it had broken motor mounts.

I recently purchased another ATI. I know it is not a performance machine by any stretch, but it was cheap and had some sentimental value. I started fixing it up last winter. I am about to finish.

It has good compression a clean spark and the clutch has been resurfaced. I put new tires, chain and sprocket on and the ignition consists of a battery and generator. I re-did the wiring and did not hook up any lights.

I was wondering if there are any ways to improve this bike for trails. I know it's not a true "dirt bike" as in serious performance, but I seem to like it anyway. Part of the reason is my limited budget. I have three kids and most money goes to that. I still like to fart around in the garage when I have some extra time. I would appreciate any feedback.

Thanks for your time

Don't sell the AT-1 short. It was great little bike. It started easy, thrived under abuse and didn't have any real bad manners. If you want to improve the handling of the bike without spending a lot of money, I would consider slipping an entire set of forks in the steering head from a 250 Yamaha or Suzuki from 1974 or 1975. You'll have stronger forks with better bump absorbing ability, and if you scout around, you should be able to get a complete set cheap.

For the rear end, the only way to go is a set of Works Performance shocks. While these aren't cheap, dollar for dollar, it's the single best thing you can do to make the bike more enjoyable to ride. Their number is (818) 701-1010. When (if ) you order the shocks, tell them you're installing longer forks and they'll build the shocks a bit longer to match the new front end. The result will be a very satisfying ride.



My name is Joe Hirsch and I live in Frankfort, Illinois. Me and my buddy bought a 1977 XR75 for 60 bucks, but it needed work. It's been a week now and we've already cleaned it up and got the engine running, but there is no muffler on it. It has the pipe and everything, but no muffler.

I called Honda and they said it would cost 128 bucks for a new one, but I don't know if I can afford it. My question is if I can get just a after market silencer for it?

Another problem is I can't find my make of model for a silencer. I've looked in Dennis Kirk and I was wondering if I could buy one for a different model and have my dad weld it on. I'm looking at a price range from about 50-80 bucks.



You're on the right track. Rather than spend much money on a bike that cost you low bucks to start with, I would simply scour the bike boneyards and find ANY four stroke muffler with the same size bore as the tail pipe on the XR. Then have your dad weld it on, and chances are very high that the bike will work just fine.

2000 WR 400F

I am a 6'2" 180 pound guy who just bought a 2000 WR 400F. I was wondering if this is a good bike for very fast trails. I was also wondering what is the best aftermarket pipe I can install for horsepower. Before I bought this bike, I was thinking about buying an XR 400R, but decided on the WR because of the higher power output. Was this a good decision? Please email me back as soon as possible!

Ray Lebreton
BC, Canada

Even though the Yamaha is a faster, much more modern bike than the XR 400, if you spend most of your time trail riding, it's hard to beat to comfort and ease of the Honda. Still, you already bought the bike, and must live with it. Consider a White Brothers of FMF pipe for your bike. I have friends who have bought these items and like the results.

Sorry, but personal email responses are not possible due to the huge volume of mail.


Hi Rick,

I just recently returned to the world of dirt biking and having a family, I had to do it on a budget. I found a Yamaha XT 200 for $50 that only needed some normal wear items and a good cleaning to be rideable.

My problem is that the exhaust pipe was all but rusted off, so being a do-it-yourself person, I made one from some 1 1/2" tubing. I also made a muffler from some 2" tubing with adapters.

The bike runs good at idle and part throttle, but falls on its face at full throttle. The carb had a 122 main jet in it stock. When I go up in jet size, it gets worse and when I go down in jet size it seems to get too lean (from 114 to 130 in increments of 2).

Is there any thing that I can do to fix this, or am I doomed to a life of short shifting and being passed by guys on four wheelers?

Scott Southworth

It sounds much more like your timing is off, rather than the problem being a restrictive home-made muffler. If the timing is retarded too much, you'll have the kind of performance you just described. Give this a shot first before you mess with the jetting any more.



"Once again, the Desert Vipers Grand Prix had gotten the best of me. But I'll be back. However, maybe I just ought to race a stock TM-400 and go real slow.

Anybody want to buy a slightly used factory race bike?"

Great story. I assume that you were kidding about selling the beast???

I have a 2 TM 400s and a TS400 engine and misc. parts. I may be bugging you for pointers on merging pieces parts into a hybrid machine, leaning more towards enduro than MX. In preparation for this project I am having a motorcycle garage sale. I figure that the project will be much easier if I can get to the TM 400 donor bikes.

Anyway, thanks for the great articles,
John Janosik
S.E. Iowa


At this point I'm down to:

  • 2 TM 400s
  • 2 1981 Honda CBXs (1 for sale)
  • 1 CB77 (not for sale until the kids get it in my estate - a long time from now)
  • 1 CB125S (not for sale, but I don't know why not, except that my wife thinks it
  • cute)
  • 1 SECA turbo (for sale)

and a basement and garage full of parts

Too late, John. I sold the factory TM 400 Cyclone and used the money to build a street-legal Class 8 off-road race truck.



I liked your article on cooling. Thanks for the info. I have a question about your Bronco. I have a stock 86 Full size with a 5.0L EFI. I have been kicking around with ideas and was wondering what setup you had? I want to build a good all around Bronco that I can use everywhere and drive there, too.

Any help would be appreciated.
Krzy Moke

Since I can't give you a whole race-truck building manual via email, here are some basic tips:

  • Use 35 inch BFG All Terrain tires. These things work everywhere.
  • Run double Rancho Series 9000 shocks on each wheel.
  • Use a good long travel aftermarket kit. Try Rancho or Superlift.
  • Use long radius arms.
  • Run 4.56 gears.
  • Install a good skid plate for the engine and tranny/t-case.
  • Install racing seats and real racing belts.
  • Slap on some serious lights.
  • Use a K & N filter.

You now have a decent pre-runner that should work just fine. Go forth and have fun.


Hey Rick,

I just discovered your online column "Don't Ask!" I like it. I'm a 14 year old amateur dirt biker from Amherst, New Hampshire. Although I started dirt biking only a few months ago, I've gotten good quickly and was nicknamed by my friends as Evil Kniazev (Kniazev is my last name), because I will try anything at least once! Lucky for me I haven't broken anything yet (still looking forward to the long hospital stays), but I have had my share of bad spills.

Anyway, I currently own a 1955 Honda CR 80 with mostly original parts. I bought it thinking could use it until next season as a starting bike, but I learn quickly and I already have a craving for more power and speed!

So I'm selling my bike and buying a 150 or higher. I would like your advice on the best size bike for me (one that's not too hard to handle). I'm about 5' 10" and weigh l30 lbs. (if that helps).

"Evil" Kniazev


Young man, you are well on your way to becoming a statistic. Try anything once, eh? Well, how about trying to leave the sport, so we don't have to put up with a newspaper headline someday that reads - "14 YEAR OLD KID FROM NEW HAMPSHIRE KILLED WHEN TRYING TO JUMP LOCAL BURGER PLACE ON A MINI BIKE."



My name is Paul Winters. Soon I will be purchasing a 1992 YZ 250. When I looked it up on, it said that YZ did nothing great, but didn't do anything poorly.

What I want to know is, will this bike give me months of awesome riding, or will I be stuck at the back of the pack? What's your opinion?

Paul Winters


That particular machine was a decent all-around bike, and for starting out racing, it's enough to be competitive in the novice or beginners classes. At this stage of racing, conditioning is much more important than a trick new bike. Just go out and have fun.



I recently picked up a 1981 YZ465 and have been experiencing some clutch problems. On the first ride, it was obvious the clutch was slipping under full throttle in 3rd, 4th and 5th gear, especially in the sand. I replaced the steel plates, friction plates and springs. The actuating arm and pushrod look to be in good shape also.

However, the clutch still slips in 5th gear from about 3/4 to full throttle. I've tried several adjustments, both at the lever and inside the clutch cover, but can't get it to stop slipping.

There is always a little slop in the cable and everything seems to move freely. I use 20-50 motor oil (Castrol or Valvoline) in the crankcase, a friend suggested trying Honda four stroke oil, which he thought was thicker(?). It seems if there was problem, the clutch would slip in all gears and not just 5th. With all the new parts I don't see how it could still be slipping. Hope you can shed some light on this.

New Mexico

PS: I've read "Monkey Butt" a few times, great entertainment.


Actually, any bike will tend to slip the clutch in the upper gears, rather than the lower ones. When I used to race the older Maicos in the desert, I found that when I ran the desert gearing, the clutch would slip a bit in top gear above half throttle. Sound familiar? But when I would change back to MX gearing, I would not experience clutch slipping at all.

My suggestion is to increase the pre-load on your clutch springs by installing a one millimeter washer on each clutch spring for starters, and perhaps two mms, if necessary. This will make the clutch pull a bit harder, but should solve the problem.


Super Hunky!!!

I just finished the article, and I must say I feel sick!!! I can not believe that you folks felt that way back in 1973! I can remember reading Dirt Bike when I was a kid in the early 80's and you were talking about the "Sierra Clubbers." This is the kind of sh*t they want!!

To this day, I cringe at the thought of those bastards gaining control of anything. Don't get me wrong, I am an avid hunter, I love the outdoors more than anything, but I also love my freedom. I used to live up north in the summers, and we went everywhere on our bikes.

I have heard the story many times from my mom, about how she used to get tears in here eyes when she would hear us across the lake, coming home from a long ride. Of course we never knew this until we were older, but it still strikes a cord. My mom, not knowing anything about bikes, could tell you if everyone was O.K., and how many bikes were returning that day.

I feel very privileged to have had the youth that I had. Not to blow your horn, but I really enjoy reading your prose again. You have answered a few of my questions and I am thankful for that. You remind me of myself.... A nose to nose.... Toes to toes kind of guy.... There are not many of our kind left..

Have a Great Day!!!
Dave Zajac


Yeah, it is sort of spooky how a story I made up is so close to what's happening now.


We are needing help finding a 1970 RM 400 oversized piston and rings. If you know a place that would have them, or have a suggestion, please email back.

Craig Haper
St. Louis


Perhaps the reason you are having problems find a piston and rings for a 1970 RM 400 is that Suzuki never made an RM in 1970. Try to get your ducks in a row before you waste my time.


Hi Rick,

I just tripped across you on the net: Super Hunky Lives! I loved your stuff in Dirt Bike when in was growing up. Great times, Honda Elsinores, Suzuki Cyclones, CZs. I was riding a tired Kaw 100, but I had big dreams and my Dad's buddies had all those bikes and they let me lose on 'em once in a while. What fun!

Last bike I had was a 1980's YZ 400F two-stroke set up for desert! Funny to see that model name recycled as a 4-stroke!

My boy Is coming of age, old enough to pull weeds and save up money for that first dirt bike. He's 5'2 and about 80 pounds. I'm steering him towards a XR 80. Any thoughts?

XR 80s and XR 100s seem pretty pricey; any under-rated small bikes I might get a better value from?

While we're at it, well, if the boys going to ride, I'll need something to ride, you know! So I can properly supervise the lad! That's what I told my wife anyway :-) She just wants me to start biking again, so I'll quit skydiving!(no joke).

Okay with me! I'm 6'4' 220 and fairly fit, and we live in the Mojave Desert about an hour from Jaw Bone Canyon. I was looking at XR600s, then WR400s. I've seen some used YZ400F's (4-stroke) for sale and thought about getting one and setting it up for desert. What do you think?

Chris Dysart


After checking out all the prices, I see that XR 80s go for a little under $2000 and XR 100s got for a little over $2000. When you consider that one is a mini bike, and the other is a genuine real small motorcycle, there's no contest. Go for the 100. He won't outgrow it. Heck, even a full-sized adult can trail ride a 100 with no sweat.

As for your needs, you might think about picking up on a clean used XR 600. Since everyone is going berserk over the new generation four strokes, these can be had at real attractive prices. Even new ones are price slashed on the showroom floor. At your size, the XR would be just fine.


We recently acquired a 1977 Yamaha DT 250 in mint shape (2250 mi.). It had sat in a garage for 21 years before being purchased by the previous owner, who cleaned up the fuel system and drove it for a couple of months before opting for a true street machine.

The bike is fouling the plugs and the dealer has ordered a new jet for the carb and a metering rod, however it seems that these are hard to come by. I am confident that eventually these parts will arrive, however are you aware of a quick and reliable source of old Yamaha parts, or is there a definitive guide on what current parts would be compatible?

Best Regards
Brian McCoubrey


Brian, I have been riding bikes for over 40 years and the one thing I have never seen is a worn out main jet. At the most, the parts in your carb probably needed cleaning. And if for some reason you had a damaged main jet (I have no idea what a metering rod is. Do you mean a needle?) or other parts, you can order them directly from Mikuni.


Hi Rick,

Love your column and "Monkey Butt" is my next acquisition. I (and my family) are new to dirt biking. We started out by getting my son an XR 80 (he's 11 and short). Then I found a screaming deal on a 1997 Yamaha XT 225 (Serow) with just 277 miles on it that suits me fine.

Next we got my very short 8 year-old daughter a PW 50. Mom has been learning to ride on my son's XR 80. She's 4'10". We're looking for a bike for her. My thoughts are that an XR 100 would be about ideal, but after sitting on one she thinks the seat height is too high. She prefers the XR 80 seat height.

Looking through the literature, the Yamaha RT 100 caught my eye (no local dealers have them in stock). It has a seat height just barely taller than the XR 80, but obviously with more power (extra ccs, plus it's a two-stroke). What are your thoughts on the RT 100? Should I let her get more comfortable on the XR 80 and then revisit the XR 100, or should we just get her an XR 80? Other bike recommendations?

Last question. Since the XR 80 and the XR 100 appear to share a frame, can the stock wheels be replaced with bigger (XR 100 size) wheels?

Mark Garetz


I've got another option for your wife to consider. Why not get the XR 100 and simply cut the saddle down to the point where she's comfortable. It's easy enough to do and the XR 100 saddle is plenty thick to start with. That's the path I'd suggest.


Do you have a used motor that runs and would be willing to sell?



Certainly. The Briggs and Stratton lawn mower motor is on its way. A bill is enclosed. Please pay immediately.

Also I have other motors that I would be willing to sell, including one from a mighty fine blender.


Dear Mr. Super Hunky Rick (Oh wise one)

Your Dirt Biking Honorable Sir:

It sure is good to see you are still there, dispensing wisdom to the many. I used to read your column every month in Dirt Bike, and its great to see you here online now. I know you probably get TONS of email like this one, but I just want you to know that you are Needed, Appreciated, and Highly Admired by us, the dirt biking masses. Your technical brilliance is unparalleled! Your Humor is side splitting! Keep up the Good Work!!!!!

L. Ledbetter
West Texas
Thanks Mom.

'85 CR25OR

Hey Rick,

Its my buddy's CR again. His house must be like possessed or something; his

Kawasaki KM 100 did the same thing till we put a new plug in it. Then it would start first kick. The CR has some weird ergos, I'll tell you that. The kick starter would make an effective pry bar, and has so much compression. It used to run real well, a first kick starter, but now, it will barely run, it will pop and snort and fart all the time. Any ideas?

I feel really bad for the kid. I could get it started easily when it ran good, but him being at 5' 4" and weighing l20 pounds, he could barely start it when it ran good, and he can't start it now for his life. It started and ran good on a new plug, but after a stuck throttle experience, it ran bad, and will hardly run. Any suggestions?

Mike Christian


Now, this might sound like a stretch, but do you think it might be possible that the bike has the top end all screwed up from the stuck throttle situation? Sure, it seems like a long shot, but who knows?


Dear Mr. Sieman:

Have you ever heard of anyone using flexible steel reeds and an electromagnet to make them respond quicker than ordinary carbon fiber/fiberglass units? We are experimenting with this process. The idea is to "bump start" the reed rather than waiting for atmospheric pressure to do it. I figure you've just about seen it all and were a good person to ask.

Followed your exploits in DB since '79. I used to live in Adelanto on the road to El Mirage dry lake (remember the first sharp turn out of Adelanto with the barn shaped house)? Used to sit and watch the bikes go by hour after hour. El Mirage is dead now.

Byron Woodruff


The reason reeds open by themselves is when the suction from the engine demands it. To open the reeds before the engine needs it, would defeat the purpose of the two-stroke Schnurle loop.



I just read your article on the great cooling saga of '99 - I like it, it shows, you know your stuff, no doubt.

I have been suffering some cooling probs lately on my rebuilt 79 Chero with AMC 360 running on LPG. I tried running without the therm, and it was worse, just not enough circulation, even just a restrictor, still too hot, put the therm back in and it was much more stable.

I recently discovered my water pump was buggered and the water jackets on the timing cover were less than desirable, so they got changed and things run better now, as well as a cooling system flush cleaner was put through to get rid of any crap in the water jackets,

I also put a water filter in the top hose to keep any crap from clogging the radiator tubes. I use a stock fan clutch and the stock shroud, too. But I run LPG (propane) at a 10.5:1 compression ratio for 95% of my driving and fuel to get between LPG fill ups. I have a 160F thermostat.

So now I run a nice 160-180F in 'warm' temps, 25*C (spring here now), but as soon as the A/C goes on, it gets up to about 200, maybe 210F. I also have a trans cooler in front of the rad and it also goes through the bottom tank of the rad as well.

I was considering bypassing the trans cooling in the bottom tank of the rad, and sending it directly to the cooler up front - will this help?

Also a mate of mine with his 83 Chero (FS) has found that wrapping the headers in that heat tape helps keep things cooler under the bonnet (hood) as well.

You mentioned putting the trans cooler up back - I assume you are talking about race vehicles there, but what other alternative is there to relocate the cooler?

Is there anything else that your great knowledge and wisdom may be able to pass on to this mere plebe? < is that good enough for sucking up?? :-)>

Speaking of fish taco's - isn't funny how we call tuna sandwiches, or salmon sandwiches just that and not fish sandwiches?

Thanks and Regards
Rod Linnett
NSW, Australia


I have placed any number of trans coolers under the truck, but out of the way of damage from rocks or brush. In all of these cases, I installed the trans cooler with a small fan to assure air flow at lower speeds. This makes a whole lot of difference in the amount of heat being sent to, or through, the radiator.

I never use the built in trans cooler in the radiator in any of my off-road trucks. Newsletter
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