| Mark
Klein is ready to answer your technical questions! Mark has extensive
experience race tuning off-road motorcycles for local and national races.
If you check back through our 1998/99 archives you will see a series
called "Dirtbikes 101." Mark brings his expertise to fielding your
maintenance and tuning questions.
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a Question Oil To Burn Please help, 45-year-old new rider.
Could be your right side crankshaft seal. It can
suck it into the crankcase area and burn it. This is the most likely place
for it to consume oil without any external leaks. Most bikes can have this
seal replaced by removing the right side cover; clutch and primary drive
gear to expose the seal. Some bikes (some Kawasakis come to mind right off
hand) require splitting the cases for this repair. This could get
expensive by the time you replace all the seals, gaskets and bearings even
if everything else inside the motor is in good condition.
Hopefully, you'll be able to gain access to the
seal without splitting the cases. With it burning that much oil, it would
probably be a good idea to repack your silencer once you get the seal
replaced. The excess oil can saturate the packing. MX Tuner Free YZ Thanks. Russ I can't imagine you'd need a 380 main jet or the
45 pilot. It seems you're headed in the right direction looking at
electrical components. Be sure to unbolt the ignition coil to guarantee
the mounting tabs are corrosion and rust free. Most of the time I run into
an electrical component causing erratic jetting, it is the CDI box. But
any one of them can give some strange symptoms. Your best bet is finding
someone with another '99 YZ 125 and start swapping parts. I'd definitely
go back to stock jetting during your diagnosing and then fine tune the
jetting once you get to the root of the problem. One other obscure thing to watch for is the float
level of each side of the float. I've seen brand-new bikes (a YZ 125 in
particular) that have the float tang bent so one side is correct and the
other is way off. This particular bike ran fine in left turns and ran
terrible in right turns. But depending how far off it is, you could have
something similar.
MX Tuner 1990 CR 125 A week before I was riding and one of the water pump hoses fell off, I
don't know for how long. Maybe a lap, I stalled out on my account and
noticed it when I looked down. Maybe because I ran it out of water?
The transmission forks where good but one, right one it is bent
slightly with wear heavy to the to the one side, is this the 1st gear
problem? I also noticed that the transmission shaft with the first 1st
gear, is one unit and one of the teeth has a chip missing from it. It
would still mesh ok but I am replacing anyways.
Problem three: The piston has been hitting the head. I noticed a ring
around the top of the piston. I looked at the head and see where it has
been hitting about a .03" ring on the one rad. it looks like it has
definitely been milled. What is the squish for a 1990 CR 125? What should
I do about this? Otherwise it is a good bike, starts on the first kick
most of the time. A lot of carbon deposits in the exhaust and HPP more
like black goop. Hope u can help me.
The choppy, grabby feel sounds like the clutch
acting up. The water-contaminated oil certainly won't help the clutch work
correctly. Check the thickness of the fiber plates. Check the metal plates
for warpage. You can do this by laying them on a piece of glass and using
a feeler gauge. Check the clutch basket and hub for notches where the
plates ride against them. If the metal plates are made of aluminum, I'd
highly recommend replacing them with steel plates. I don't remember what
that bike came with from the factory. The aluminum plates are slightly
better for performance but are much worse for durability and clutch feel. The shift fork with any signs of wear must be
replaced. Even if it isn't bent, the wear is enough to condemn it. The $35
or so it'll cost is a drop in the bucket if you have to pull it apart
again. Has the piston actually been hitting the head or
is the markings you're seeing signs of detonation? Either way, I'd
recommend having the head remachined by someone who knows what they are
doing. Eric Gorr would be an excellent choice for this work. Don't take
this lightly. If this isn't done right, you can have a bike that runs
fine? until the piston develops a new hole in the top of it. Eric can be
reached at www.eric-gorr.com. Tell
him I sent you. MX Tuner 175 PE Suzuki 1981 Thanks - Patrick You'll need to remove the right side cover to
inspect the kickstart mechanism. You may also have to remove the clutch,
depending on what you discover once you get in there. If it were anything
else, you'd have a different symptom. A good visual inspection should
reveal your problem. MX Tuner 2000 Yamaha YZ80 1. It has a pinging or tinging sound during idle and through the power
range; however it is less noticeable when revving, sounds like it is
coming from the engine.
2. It is dripping oil or goo out the tail pipe. The spark plug
according to the book is running rich. It is wet and black-coated. We bought the bike at an elevation of 2700 feet and live and ride at an
elevation of 4700. I have checked the flywheel and it is tight, no leaks. We are using a
mixture of 45:1 using Bell Ray synthetic oil per the previous owners
recommendation. The Needle is set to its leanest point. The plug was oil
coated and wet even when it was pulled and replaced by the person we
bought it from. And the boy riding it was an experienced rider. However
the goo out the tailpipe was not there when we got it. Does this tell you
anything & any recommendations, please? Thank You Hard to guess what the noise might be without
actually listening to it. If it needs a top end, and with 6 months on it-
it probably does, then plan on doing that and inspecting the lower rod
bearing when you have the top end off. The rod should move side-to-side
but should have no perceptible up and down play. It can be difficult to
move it exactly up and down without getting some side play to confuse
matters. Even a 2000 model bike may need a crank rebuild if the air filter
wasn't cleaned adequately or if it sucked dirt sometime in the past. I've
seen a crank get ruined in as little as 15 minutes once an air filter
comes loose or some similar problem resulting in unfiltered air being run
through a motor. Then again, they make a bit of noise even when new.
The goo is a jetting issue. Even at 2700 feet,
the stock jetting would be too rich unless it was pretty cold outside. At
4700 feet, it's even farther from optimum. The needle position is one of a
few ways to alter the fuel/air mixture. The needle position controls one
throttle setting. The air screw controls up to 1/8 throttle opening, the
pilot jet controls 1/8 to ¼throttle, the needle controls ¼
to ½throttle and the main controls ½to full throttle.
There are other variables like the slide cutaway but you should only
concern yourself with the airscrew, pilot jet, needle position and the
main jet in your attempt to control the spooge. There are a number of on-line jetting guides and
articles. Eric Gorr has a good one on his site at www.eric-gorr.com.
Before you begin any jetting, make certain your silencer is on good
condition (silencer packing fresh and the core holes are clear and
unobstructed). A silencer in need of repacking will give rich symptoms. MX Tuner
Lighting A TTR Thanks - Len I would check with Baja Designs for some possible
options. I know they do a number of different lighting kits and do stator
mods and rewinding. I believe their website is at www.bajadesigns.com. MX Tuner
Butterfly Powervalve Thanks: Jesse One of the best investments you can make for your
bike is a shop manual. This will give exploded views and specifications
and torque specs that are critical. MX Tuner
New XR Burning Oil -Greg Any number of things may have happened. I would
try to get as accurate a number of actual usage as you can. How far do you
go before it needs a ½quart of oil? You need to be as consistent
in the method of checking the oil as you can. Be aware of the fact oil
expands with temp and can affect your readings. The oil level can vary
substantially from cold to operating temp. The oil level needs to be at
the full mark when it is at operating temperature. Once you get an actual
distance number of usage, then go to your dealer and explain the situation
with the facts you have. This will go a long way in getting the problem
remedied. MX Tuner No Second Gear I have a 1987 Honda XR200R. It somehow ran out of oil and second gear
went on it. When I try to shift to second it acts like a neutral gear. Can
you tell me what I have to fix and or what I should replace I truly doubt if the lack of oil has anything to
do with your 2nd gear problem. The engine would quit running before the
transmission would fail. In any case, the gear or the respective shift
fork itself is faulty. Either way, the engine needs to come out of the
frame and be totally disassembled to get to the gears. Chances are, the
dogs (the teeth on the side of the gear that mesh with the corresponding
gear next to it) are rounded. You're looking at probably a $500 repair to
fix this. MX Tuner Bent Disk - No Brakes I have a 1999 YZ 125 and I have no pressure in my front brake. I have
bled the brakes a couple of times I still have no pressure. I had a fall
while riding and bent my front disc a little and noticed about 2 hours
later when done riding, could that have anything to do with my front brake
pads not moving at all and no pressure. I also blew the brake cable out
with a compressed air pump. What could be the problem? The lack of brakes directly after a fall points
to a bent disc. But this usually gives a symptom of the brakes pump up
fine sitting still and then get soft once the bike is rolled. This is due
to the caliper piston being pushed back by the bend in the disc as it
passes between the brake pads. But it sounds like you have something more than
this going on. When installing a new brake line, I attach it to the master
cylinder but leave the caliper end disconnected first. Pinch the banjo
fitting between your fingers while holding the end at a point higher than
the master cylinder. You can feel the slightest pressure build when
pumping the lever. When you feel a little pressure build, let the pressure
go and squeeze the end of the hose again before releasing the lever. This
way, you can bleed virtually all the air from the hose itself. Now connect
it to the caliper as quickly as you can so you allow the least amount of
air into the hose as possible. Have the caliper unbolted from the fork so
you can raise it up over the level of the master cylinder.
Now the tricky part. You need to bleed the
caliper but you need to hold it so the bleeder screw is at the highest
point. You may need a 3rd hand to help squeeze the lever and refill the
reservoir as you open and close the bleeder screw. Once you get as much of
the air out that way, bolt the caliper to the fork. One method I've had
good luck with is to use a screwdriver to spread the pads apart. This
pushes the air bubble up the brake hose instead of fighting to get it to
go against gravity. Once you spread the pads, pump the lever to extend the
piston again. Bleed it through the bleed screw once the caliper is bolted
in place to get the last little bit of air out of the caliper. Then keep
doing the pad spreading method to get the last of the air out of the hose.
This has been the most successful way I've had to get 100% of the air out
of the brake system. MX Tuner Woods YZ? Any help would be GREATLY appreciated. Thanks, Jeff A flywheel weight would be the first place to
start. The least amount of weight I'd put on would be 10 ounces. You're
better off with 12 or even more. The weight won't slow the bike down; it
will just slow its tendency to rev out so quickly. It'll help allow it to
get traction with the rear tire easier and in more adverse conditions. I'd
be surprised if you wanted to take the weight off for motocross use after
you've ridden it with the weight. You could change the cam timing to WR
specs but I think I'd do that as a last resort. One problem with using a YZ in the woods is the
tall first gear. You might try a one tooth smaller front sprocket to bring
the gear ratios into a more useable range. That way, you'd get a
substantial difference and could swap back to the stock front sprocket
when you get ready to hit the MX track. Even with a gearing change, you still may find
yourself using the clutch enough to make it need adjusting in some tight
sections. Once the clutch cools back off a few degrees, the free play
normally returns to where it was. A hydraulic clutch will automatically
compensate for this. I've installed a Hebo hydraulic clutch kit on a
number of YZ and WR Yamahas with excellent results. One side benefit is
greatly reduced clutch lever pull. Hebo is the supplier for Gas Gas OEM
hydraulic clutch components. Your local Gas Gas dealer should be able to
order the universal kit through their accessory division. MX Tuner
Gotta Go Faster Thanks, Jeff Personally, I've had truly remarkable results
using the V-Force reed cage. The only mods I've done that give a larger
increase in overall power are either a major cylinder porting or a big
bore kit. The V-Force reed cage comes with an adjustable
reed stop. I've found the low-tension setting is preferred by virtually
all riders. This gives a substantial increase over the entire rev range.
The key to getting full benefit from the V-Force reed is to lean the
jetting once the reed is installed. You'll need to lean the jetting across
the entire range (pilot, needle and main). In my opinion (and I'm not paid
or compensated by V-Force), once jetted, dollar for dollar, this is the
best single mod you can do to a two stroke. Otherwise, the sky is the limit concerning mods.
A quality porting can make a big difference, not just in peak power but
also to alter the power output to meet your desires and riding style. A
2mm overbore makes a big difference but then you're starting to get into
spending a good chunk of change. Boring and replating can run into the
$400+ range (including the piston kit) not including labor to remove and
install your cylinder. Obviously, a pipe and silencer can give a
substantial increase. And just like the reeds, the jetting needs to be
fine tuned to get the full benefit. MX Tuner
Clutchless In PA Pissed in PA, Pounder
There is a rack type gear sticking out of the
center of the clutch that has to engage with the actuating shaft in the
clutch cover. If you get it a tooth off, it'll give the symptoms you have.
There is actually a set of marks on the side cover that should line up
with the end of the actuating arm when everything is timed correctly. The
end of the arm is at a slight point and that should ride directly between
the two ridges cast into the cover below the arm (where the cable hooks to
it). MX Tuner Jetting - 2000 YZ125 Jarad, El Cajon, CA
There are way too many variables to give exact
numbers but I've been using 430 or 440 mains (about 1000 ft elevation)
with a pilot in the 27.5 range. Needle position set for crispest throttle
response. First of all, your main is way too rich. Before doing any
jetting, make sure the reeds are in good condition, the float level is
correct and the silencer is not in need of repacking. Even a fairly new
silencer may need repacking if the packing gets saturated or the holes get
glazed over. MX Tuner
Year: 1999 I recently purchased my Honda. On the first crack of the throttle, it
hesitates or cuts out. I have a 1982 XR500R that rips off the line
quicker. The 500 is stock with a K&N air filter. The 600 is also bone
stock with the end cap of muffler taken out. The only thing I have tried
is to lower the clip on the needle with not much change. Am I just
twisting the throttle too fast to start? Are there any mods I can make to
remedy this annoying problem? Wade
Colorado Springs, Co
The needle position controls the jetting at ¼
to ½ throttle settings, not right off idle. You can try a couple
things pretty easily. One is to try adjusting the mixture screw. Try
richening it up about ¼turn at a time. If that doesn't give
satisfactory results, you might try raising the idle speed up just a
little. This can help reduce/eliminate the hesitation. Otherwise, you
might need a richer pilot jet. MX Tuner
Broken Gears Seems fairly obvious that something broke off and
got wedged in between something else. Just what came first is hard to
tell. Sort of the "What came first- the chicken or the egg?" type thing.
As long as you have replaced all damaged parts and have thoroughly cleaned
out the bottom end, you should be fine. Whatever broke the gears was a
relatively big piece- not a small metal shaving. MX Tuner Sir,
The front brake on my '95 KX 250 is sticking. The wheel turns when I
ride the bike but when I put it on a stand and try to spin the front wheel
it's almost locked in place. I flushed - the brake still sticks. Any
suggestions on how to fix my problem will be greatly appreciated. Winston Sounds like you may have the master cylinder push
rod clearance adjusted too tight or the piston itself isn't returning. You
need to verify that you have some free play in between the lever and the
master cylinder piston/pushrod. If it isn't returning 100%, then it will
do exactly what you're experiencing. There is a return port inside the
master cylinder that won't release the hydraulic pressure if it is
covered. This is in the last millimeter or so of the piston travel. I have seen an unusual circumstance that gave the
same problem. There is a small rubber boot right at the end of the master
cylinder where the pushrod goes in. This prevents dirt and grime from
getting in to the guts of the master cylinder. Some rubber boots have a
small metal circlips made into the outer edge of the boot. I ran into a
KTM that had this circlips out of place and holding the piston pushed in
about 1mm. This was all it took to lock up the front wheel after a short
ride. The one way to verify if the source of the
binding is mechanical or hydraulic is to open the bleeder screw. If the
release of hydraulic pressure frees up the wheel, then you know the
problem is at the master cylinder. If not, you have a slider that may be
bent or some other issue at the caliper. MX Tuner Low End Bog I have since tried an infinite number of jetting combinations to
compensate for the increase in airflow. The problem I am having is a bog
or engine cut out at about quarter throttle when the throttle is opened
quickly. Sometimes if the throttle is opened quickly and is held at
quarter throttle the engine will actually die. I have tried many main jet
settings in combination with pilot jets, needle position, airscrew
adjustments trying to keep the main jet as a constant while checking the
other settings. Then changing the main jet and doing it all over again. I now own every jet and needle made for this bike!!!!! I can't seem to
get rid of the bog. It is very frustrating when you need a quick burst of
power and its not there just about sending you over the bars when it cuts
out!!! The problem seems to be slightly more noticeable when you have the
bike slightly lugged down in a taller gear and snap the throttle open. I live and ride in Washington at usually 0-4000 ft. and would love some
advise. The bike runs like a champ once you get past the bog. I know there
is an answer! PLEASE HELP!! Jason Seems you've eliminated jetting as the problem. I
think I'd start investigating other areas like the accelerator pump. Does the bike run normally with the baffle and
air box top installed? MX Tuner Pinging TTR I just purchased a new 01' TTR225. Low-end power seems fine. But when I
get up around 1/2 throttle it begins to ping and sounds like it is
breaking up. Yamaha suggests a 10 hr. break in period. I have about 6 hrs.
on it now. I have been waiting to see if it gets better as it gets more
broken in. I brought it back to the dealer twice and basically they rode
it around for a few minutes and said it was fine.
Am I nuts? This would be nice.
Thank you Chip No, your 225 should run fine all the way up to
redline rpm. You shouldn't rev it that high yet since you can create
oil-burning issues later in the life of the bike if proper break in isn't
followed. But it should still run okay. It shouldn't ping at all. I'm
assuming you're using a decent fuel like any readily available premium
unleaded pump gas. The carb float level being too low can give the exact
symptoms you describe. If your local dealer isn't any more cooperative
than that, a call to the regional corporate Yamaha office may get the ball
rolling. MX Tuner
Rattling RM Richard
When you say the motor has been completely
rebuilt, do you mean the bottom end also? Were the crank bearings
replaced? Does the noise go away when the clutch lever is pulled in? Are
the motor mount bolts adequately tight? Was it rebored and a new piston
installed? Are you certain the people who bored the cylinder set eh
piston/cylinder clearance properly? Type F ATF is a good lubricant that can make a
good shifting bike shift even better. It can improve clutch feel and
action. Your 465 will do just fine with the ATF. Like any other
two-stroke, just keep the fluid fresh by changing it frequently. This
needs to be done whether you use ATF or any other oil. MX Tuner Thinner Gaskets? I have a 2000 XR400R and have been looking for a source for a gasket
kit that will increase my compression by decreasing the thickness of the
gaskets. What company is the best source for such kits? Thanks, Hans Cometic makes high compression gasket kits for
two strokes. I don't have a Cometic catalog but I do know they can, and
will, make any gasket any thickness out of any material you need. A call
to Cometic should get you what you need. MX Tuner
Shock Valving Diagram Thanks, Mike
I don't know of anywhere that those specs might
be listed. What are you trying to accomplish? Are you trying to reassemble
a basket of loose parts? Are you trying to revalve the stock shock? I may
be able to get you some good info if I know exactly what you're trying to
achieve. MX Tuner New Reeds, No Bottom
I'm not sure what you mean by "opening " the
reeds up. The stop plate is adjustable. You need to set it on the
low-tension setting. This is the only adjustment possible on that, or any
reed. If you didn't notice a substantial improvement
with that reed set up, then one of two things is going on. One is you didn't
rejet to compensate for the reed cage or two; you have some basic
mechanical issues that need to be corrected. Something like the power
valve stuck in the open position maybe. MX Tuner
Good Spark & Compression But Will Not Start 2 weeks ago I tore the bike apart and put in a new piston and rings
because I was told that it needed a new top end and that's why it won't
run. I noticed that the stock rings were in their grooves when I removed
the cylinder. I showed the head and cylinder to a mechanic and he said
everything looks good with the parts. So I put the bike together and it
fired up on the first kick. The bike ran great for 2 weeks. I broke in the piston and rings
correctly and put on about 30 easy miles on the bike, and then it would
not start again. There were no strange sounds coming from the engine when
it ran. The bike has plenty of compression when you try to kick it over and it
will not even start when you try to roll start it. The bike has very few
total hours on it and I only trail ride it. I also run my oil at 40 to 1.
Could this be an electrical problem? If so, how can I fix it? Thank you, Mark If it were an electrical problem, it must be
delivering spark at the wrong time (since you say it has a good spark).
Normally this would give some backfiring or sporadic popping when you try
to kick it over. Are there any rags in the air box (I've been bit
by that one before)? Is the exhaust plugged? Did any 5-year-old hands put
their favorite toy in the silencer? Is it getting too much fuel? If the
float needle isn't shutting off the fuel flow, it may just be way too rich
and is flooding and gas fouling the spark plug. MX Tuner Pops On Top Thank u, Chris The timing is fine. Oops, sorry, it was fine. The
popping is a fuel/air mixture issue. Chances are you have an air leak
somewhere. I'd do a crankcase pressure test. Be sure to check the
transmission vent hose for pressure when doing the test. This would
indicate the center case joint is leaking. MX Tuner
Yamaha XT 250, 2000 model. What can I do to improve the suspension (front and rear) without
spending too much time and money? Thanks, Eddie I'm not familiar with the XT 250 specifically.
The thing I'm not sure of is the suspension adjustments. If the rear
spring preload is adjustable, setting that for your weight would be the
first place to start. Increasing compression damping settings would also
be one of the first things to do. The forks can be improved immensely by simply
adding more oil to them. Use a syringe and add 10ccs of 5-wt fork oil to
each leg until the bottoming has been reduced to an acceptable level. You
may have to add 30 or 40 ccs. The oil level from the factory is generally
somewhere within a wide range. Changing the oil so you know the oil is
fresh and you know the oil level would be a good idea but you can do the
adding oil trick very easily. You'll have to remove the fork cap to add
the oil. Loosen the top triple clamp pinch bolts before you try to loosen
the fork caps. MX Tuner How Much Oil? It should have the oil quantity cast into the
side cover right next to the oil filler cap. It should be in the 650ccs
range (about 2/3 of a quart). You can use any number of different oils.
Everything from the high dollar two-stroke gear lubes (not my first
choice) to automotive Type F Automatic Transmission Fluid. The owner's
manual lists a specification for automotive engine oils. So you can use
auto engine oil, Type F ATF, or the specialty gear oil. Whatever you
choose to use, I'd recommend changing it frequently. This means the $1.50
a quart Type F is by far a much more cost effective choice than the $8 per
quart gear lubes. You'll be fine simply using thicker weight auto
engine oil, such as Castrol 20w50, or something similar. Just be sure to
change it frequently. MX Tuner Frozen Fork Sounds like you have a large dent in one of the
fork tubes. If you look at the lower part of the leg, you'll probably find
a fairly large area where it has taken an impact. Once you get the forks
extended, you'll have to replace the damaged part. There isn't any way to
repair something like that properly. MX Tuner Hello, I own a 1985 KX125 and I need new plastics and such. I was
wondering if there any newer years that I can buy plastics for that will
fit my bike and give it a newer look? Nothing but what is designed to fit your year
model bike will fit properly, if at all. Sorry. MX Tuner I own a 1994 CR250. When ridding mid to full throttle I get this noise
that sounds like a handful of rocks hitting my front fender. I had Eric
Gorr port the cylinder and I used a cometic high compression gasket set
with a vertex piston. I am running a 1370 needle in position 4 and a 175
main with a 55 pilot. Air filter and silencer are both fresh. I check the
resistance on the coil and stator everything was in spec. I cleaned them
and put dielectric grease on all the connectors. I run 94 octane with
Maxima 927 @ 40.1.I am running out of things to try I don't think its
compression because it's not high pitched pinging. Its like um like I said
a handful of rocks hitting the front fender. Please help. Chances are you're hearing some detonation. The
high compression gasket kit is a good mod for a stock head and cylinder.
Once you get the higher than stock gasket set combined with 94 octane, you
get a very good possibility of detonation. MX Tuner Busted Housing It depends on how good of a welder you can find
as to whether it can be fixed at all. That can be very difficult to
repair. Your chances increase dramatically if you have the piece that
broke off. Otherwise, yes you'll have to split the cases to do a job worth
attempting. MX Tuner I Need Some Help Here, Please? It has a new piston and ring. Cylinder looks good. I use hi test pump
gas and Yamaha 2-cycle oil 32 to 1. The plug comes out very oily somewhat
black. Carb has a 170 main jet, and the needle is the right one for the
carb and the clip is at the top not on the third one like the books says
no improvement. Has a new needle valve for fuel shut off. Reeds are closed, exhaust is
open, and all look good. Does not have a front-wheel-popping get up and
go. Can crank case oil get into the cylinder from bad seals? Is the carb
leaking gas into the crankcase we turn off the gas when not in use. Oil
mixture, wrong? Too big a jet, need to run racing fuel? Am at a loss and
out of spark plugs. Any advise please. Tony
Sounds like you may have a right side crank seal
leaking gear oil into the bottom end. This would be the most likely thing
causing your symptoms. Doing an accurate crankcase pressure test can be
more involved than simply changing your right side crank seal. MX Tuner
Sparkless Wonder Mike There are specs for resistance values between
certain terminals but those will only be listed in an ATK service manual.
I'd suggest buying the manual yourself and then all you'll need is a
digital volt/ohmmeter to test it yourself. Just remember that the specs and any readings you
get have to be taken with a grain of salt. In other words, if they call
for a spec of 250 ohms max and you get 261 ohms, then I don't think that
much over the limit would be enough to condemn the part. Due to the
sensitivity of a decent volt/ohmmeter, the readings can vary due to normal
added resistance from dirty connectors and such. By the same token, you
can have a component that checks exactly right and is still faulty. MX Tuner Going Buggy! Last weekend I was driving and all was goin well until the chain fell
off and I had to stop the engine. After fixing up the chain, I started the
engine the idle was fine but as soon as I put some throttle on it starts
to thump and not rev out as it did before. But the weird thing is the idle
is perfect. I have checked the timing and its fine; I have cleaned out the carby
and no hope there. Changed the plug. Today I was trying to fix it. As the engine was running I moved the
carby around and holding at a position the engine was running perfect but
as soon as I let go of the carby it went back to the thumping and low
revs. Can you please help what could it be. Oh, another thing - where is the
high-end pilot jet?? Thanks Sounds like you have a torn intake boot or some
other air leak at the carb. Look closely at the rubber boot that the carb
attaches to. I'm not sure what you're asking about the "high
end pilot jet". The pilot jet is located in the bottom of the carb but
that controls a low speed/low throttle opening circuit. The main jet (also
located in the bottom of the carb) controls the high-speed circuits. MX Tuner |
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