Each month we receive an overwhelming amount of technical questions from our readers. Everyone at ATVR including the night janitor carries an extremely heavy workload, so as a last resort we were forced to put Mike Newsom in charge of answering your questions. Mikey is one of the most talented mechanics we know, but it's his off-the-wall remarks and repulsive attitude that keep him locked away in the garage. If you dare to bear his response, send your questions to firstname.lastname@example.org. We promise not to let Mikey use your name and embarrass you in front of your buddies.
Ask: I have a QuadRunner 4WD and after driving about a mile the motor dies as though I'd just turned it off. If I try and restart right away, it will not fire, but if I wait about three or four minutes, it will start right up and run fine for about another mile then cut off again. If I blow into the vent tube, I can barely get any air to flow into the gas tank. Any help would be greatly appreciated.
Mikey: You obviously already know that your tank must be vented for proper fuel flow or you wouldn't have been blowing into the vent. It's odd that you had the basic skills to discover the culprit to your machine's problem but still feel you need Mikey's help. I hope this isn't due to a loss of brain cells from unwittingly inhaling gasoline vapors while blowing into the vent. If so, the damage has already occurred and is irreversible. You'll just have to put additional effort into the repair of your fuel tank's vent system.
Ask: How do I bypass the Yun Ba alarm on a Chinese ATV?
Mikey: Are you kidding me? What the heck is a Yun Ba alarm? I'm not going to bother researching this nonsense to find you an answer. Your problem lies at the end of your question. Chinese ATV! Toss that anchor into a lake and go buy yourself a reputable ATV that you won't be embarrassed to ride while the neighbors are watching.
Ask: OK, I have a '99 Yamaha Warrior that's been bored 40 over with a stage 2 hot cam and an FMF pipe. It has no throttle response at all. What can I do to get more throttle response? If you think jetting is my problem, what size jet should I use?
Mikey: The Yamaha Warrior is no slouch, so if you're getting waxed by your little brother's Power Wheels, you definitely have a problem. Then again, if you're expecting your Warrior to perform like the newer high-revving four-strokes such as the YFZ450, you have another thing coming. It could be a jetting issue that's causing your concern. The pilot jet controls fuel up to about a quarter throttle, the needle controls from one-quarter to three-quarter throttle and the main jet controls three-quarter to full throttle. It would be hard to give you exact jet sizes, but I can tell you that if you haven't made necessary adjustments to your carburetor since adding the performance products, your Warrior is running extremely lean and this isn't good. I'll try to put together a basic jetting guide and upload it to www.atvrideronline.com. My personal thoughts are that you probably couldn't handle that Warrior even if it were properly tuned.