There is a silver colored device located between the engine and air filter box, on a dirt bike. The contraption is known as - a carburetor. It has been termed a lots of other peculiar names, besides carburetor. Here is a sample: Bing, Mikuni, Keihin, Amal (read the word twice, please) and Dell'orto. For many years, probably more like decades, I only recognized these words, and what they referred to. One day I deduced, all by myself, one meaningful dirt bike carburetor concept. The earth will move and the sky will shake after you read this! Dirt bike engine performance is drastically altered when the carburetor is removed. Not bad huh?

Tell me honestly, did the cosmos shudder?

It was not long ago that common carburetor tuning buzzwords and phrases were nearly, such as, "...changing jets or needle jets...", "...moving needle clip positions...", "...using different slide cutaways...", "...altering choke circuits..." were almost meaningless to me.

I was never required to change "jets" in a carburetor. All dirt bikes I owned were Japanese models. Usually, the carburetion was just fine, in stock form. Also, the elevation changes in the area I rode were very mild. Elevation changes never forced me to alter carburetor "jets". All I really knew for sure was the carburetor was meant to remain attached to the engine. Hence, I wandered, dragging my knuckles, fat, dumb, and happy in a haze of dirt bike carburetor jetting bliss. Until one day...

I decided that I really, really, I mean really, wanted to fork over $5200 for a brand spanking new '95 KTM 300 EX/C! The bike received nothing but rave reviews. It had suspension characteristics that worked for nearly everyone, anywhere! Everyone that rode the machine noted the engine produced strong, smooth, and tractable power everywhere in the RPM range! It had white plastic covered with beautiful graphics containing every color in the known universe! I nearly peed myself in excitement the day I bought it.

I nearly peed myself in horror the first time I rode my new KTM. The engine performance was worse than rotten! The engine did not run smoothly or cleanly, no matter what the throttle position. It just blubbered, like a little kids bath toy, sinking in bathtub water. In addition, the bike consumed a whopping 3 gallons of pre-mix in 23 miles! I was panicked half to death. Was this the European dirt bike mystique I heard so many Husky and KTM owners blither about? Or did I just blow $5200?

This forced me to make a journey to Marty's house. Marty was generally noted as the dirt bike trouble shooting guru for our riding group. Marty reminded me of Wilson on Home Improvement, except Marty was younger, he did not wear odd hats, and I could always see Marty's face! I explained my problem in detail. He listened politely while he continued working on his latest project, lining the inside of his DR 350 fuel petcock with some sort of space age Teflon material. Marty was always experimenting with some weird thing on his bike. When I finished, Marty looked at me and stated, quite matter of factly, 'Your KTM carburetor is jetted rich. That's all Kirk. Once you re-jet the carb, the engine will clean up and your fuel mileage will really go up."

Marty walked over to his bench and rooted under two feet of amassed stuff on his work bench and magically produced two small pieces of brass. "See these? The small one is a main jet and the big one is a pilot jet. Both jets have tiny numbers stamped into them so you know what size jet you're dealing with." I held the tiny brass pieces just right in the garage light. Sure enough, one had #42 stamped on it, the other had #170. Marty's mini-seminar continued.

"Take your carburetor off, open up the float bowl and replace the jets in it with these. It'll make a big difference." I just stood there in wide-eyed wonderment at Marty's wisdom. Several flies explored the inner reaches of my gaping mouth as Marty's carburetor chronicle proceeded.

"The Euro bikes are always jetted super rich. They figure it's better to sell a new bike with rich jetting. It keeps the anxious new owner, like you, from blowing the bikes engine to tiny bits on the first ride."

I thanked my friend and went home.

It was a humid evening and storm clouds were brewing, so I figured it would be a great time to use what I learned. Reeking with new found mechanical confidence, and enough knowledge to make me dangerous, I entered the garage. After slipping into a very old and grungy pair of overalls, that had a patch over the left chest pocket that said, "BOB's OILFIELD SERVICE - BELFIELD, ND", I prepared to delve into the mysterious regions of my KTM's carburetor! But first I needed some music. I looked for some tapes on the work bench. Let's see here - The Very Best of Donna Fargo. No... it looked like an abandoned tape my wife bought long ago, and she probably will not admit buying it. Hmm... let's see here, oh... here's one! Phlem - Live and Spittin'! The 1995 Karnal Koncert Tour. Nope. Looks like one of my teenage step-sons weird rock tapes. Ah yes, here's one for me! 60's TV Show Theme Tunes. I put the tape in and pressed PLAY.

The work commenced. Theme music from the Mission: Impossible (Mission: Implausible?) began playing and I started working into a raging sweat. As I was furiously laboring, it dawned on me that it sure would be nice to have more light on the area I was wrenching on. But, it would be impossible to hold a trouble light and turn wrenches simultaneously. That's when an idea flashed before me. I knew the kids had a couple of those real tiny penlight flashlights that ran on those extra small AAAAAA batteries. After spending an hour and half rummaging through their stuff, I came up with two penlights, that actually worked. I bounded back into the garage and blacktaped the tiny lights onto the bows of my eyeglasses! Man, this wrked great! The area where my hands were working was finally well lit! There was a drawback, though. It evening was warm and humid. I was perspiring a lagoon of sweat. The sweat would collect on the taped penlights, then drip onto my cheeks. This became super annoying because it tickled my cheeks and I'd have to stop and wipe off the sweat. Again, an idea flashed before me! I dug into my rag box and found a light purple rag enhanced with bright green fluorescent stripes. Then I found two good sized rubber bands. I placed the rag over my face, like a surgeon's mask, and held the thing on by putting the rubber bands over the mask and around the back of my head. Voila! Here was something that would prevent the sweat from tickling me.

Nothing could stop me now! I kept disassembling the various KTM components. Finally I was ready to extract the mysterious silver device lodged in the KTM. I carefully pulled the carburetor out of its resting place. As I pulled, a seemingly endless quantity of plastic tubes attached to the carb followed. Carefully, and with the precision of a Master Jeweler, I unbolted the carburetor bottom and removed the bowl. Suddenly, something fell from the carburetor bottom. Collecting myself from this surprise, I examined these black 'whach-a-ma-call-ums' and determined that since they were black, these were not the things that needed to be replaced. I examined the bowels of the carburetor more intensely. A-ha!!! There they were!!! Everything I heard was true! There were replaceable jets in the carburetor; and I held the magic jets that were going to make my KTM run - just like the magazines said it did! I took my tools and carefully removed the jets and just then the tape stopped in the box and the garage was suddenly void of music. I got up, went to the box, flipped the tape over and pressed PLAY. I went back to my work and replaced the jets. Now I was feverish with excitement because I knew that I could modify my carburetor! I bolted the carb bowl back on. In an emotional moment of pride, accomplishment, and technical ecstasy, I held the carburetor high above me and loudly proclaimed, "Carburetor - Give my KTM... LIFE!" Lightning flashed through the garage window and thunder boomed outside adding to the ludicrous situation. And then the door to the garage opened. There stood my lovely, caring, and utterly dumbfounded wife.

Place yourself in my wife's shoes for a moment. How would you feel if you opened the door to the garage and saw someone you were supposed to love and care for, (for a lifetime) standing, with a purple rag over their face, in a raggy pair of overalls that say BOB's OILFIELD SERVICE, holding a dinky motorcycle part high in the air like it was a sacrifice to some obscure god, in the midst of a torn down motorcycle that appears as though its going through a bad autopsy, as theme music from Star Trek plays in the background, looking at you with little flashlights taped to their eyeglasses?

My wife laboriously inhaled a lung full of air, crossed her arms and leaned against the door jamb and spoke, in a monotonously annoyed tone, "Dear, phone call." I stepped sheepishly into the house and took the call. It was one of those telemarketing types trying to sell grave plots or something like that. I politely asked if they would bring a sample grave plot to my house so I could see what they were like, then hung up. I tiptoed around my wife, who had not stopped staring at me, and went back into the garage.

I put my KTM back together. It was time for the moment of truth. I turned the petcock on, choked the carb, and kicked the bike to life. It didn't seem to run any better. I idled the bike over to an abandoned trail next to our house and rode the dickens out of it. Still, it did not run any better. I idled the bike back home and put it in the garage.

After placing the KTM on its custom Corvette rim bike stand, I placed my tired bottom on a custom Gate City Dairy milk crate that I kinda' "borrowed" from my friend Todd. I figured I'd give it back sometime, soon. As I sat giving myself a dandy case of waffle butt, I pondered the social significance of combining mental therapy, Prozac, and dirt bike mechanics. It was then I saw a brassy gleam out of the corner of my eye on the work bench. I got up and looked at the remaining brass carb jets. I picked them up and looked a bit closer. The numbers stamped into one jet read #42 and # 170 on the other. I thought back for a moment. In my rush to get my bike going again, I put the same jets back in the carb after I flipped the tape over in the box. (I know some of you folks out there have done something similar to this!)

I started to tape the little flashlights back on my glasses and before I began tearing into my KTM again - I locked the garage door!

Kirk Overby can be emailed at kirk@off-road.com