00' 426 CLUTCH

I bought my 00' 426 used, from someone who had barely road the thing. I doubt if he checked anything on the bike, let alone the clutch. While racing AMA D-37, I notice once or twice during the race, the bike will slip out of gear, or at least seem like it. I usually don't use the clutch while I'm shifting in high RPMs, and usually it slips out between 3 - 5. Is this a clutch problem? Should I consider a Hinson Clutch basket? Any ideas? Different crankcase oil (MOBIL 1 synthetic)?

Other than that, the bike runs like a champion! Couldn't be happier. Except, I haven't been too impressed with the Hot Start button. I re-jetted the carb, with suggestions from this page, and the bike starts better, when it's hot, not using the button, and I'm sure it's installed properly (7-8 o'clock on the carb).

This is a great page guys. Thanks for keeping it real!!!!!!

Bnicol 104

My 426 also tends to wander in the 3 to 5 range, sometimes momentarily finding a false neutral before re-engaging fourth. I don’t want to scare you but on one occasion this sensation was immediately followed by my tranny fragging four gears, a shift fork, the cases and my crank. I replaced the parts and it is still prone to this problem, so I think it is inherent to the tranny and wasn’t just a defective part. Not the best advice, but it appears your options are:

1) Split the cases and have a look at third and fourth gears (dogs, teeth, forks, splines).

2) Try not to think about it.

Speaking of defective parts, both fourth gears had pitted teeth on my bike, this part is a known weak link in the ’00 YZ, every now and then someone will report losing fourth gear. When I reinstalled all the gears I had to polish the splines on the main shaft to get third pinion to engage fifth gear dogs solidly, but I don’t know for sure if this is what caused the damage (but it could have).

If you are referring to the Terrycable bar-mounted hot start system you can check to see if air is reaching the motor by blowing in the hose. But be aware that if you are off by more than 40 degrees or so on the fitting the hose will be venting the air box, so you will be able to blow in the hose but the air isn’t going to the motor, you should be able to hear it inside the air box if you listen closely however. The hot start should only be needed if you’ve flooded the bike (like if you drop it).

Hope this helps!

BTW keep in mind that for every bike that had a tranny failure there are probably 1,000 or more taking wholesale abuse without complaint. So the odds are that #2 above is an acceptable course of action for you.

I lost 4th gear on my 00426 after two months of riding it. I know that many of the members here know me well and know the crap I endured to get my bike back with no help from YMC, but when I read stories like these, it just pisses me off to no end that YMC made a lemon out of my 426. I will not buy another Yamaha this year or any year until I see some compassion toward other Yamaha owners from YMC. That's my peace. If you have complaints, I believe a forum is going to begin about complaints toward YMC.

I rode Honda's for 8 years straight and never had a tranny failure and rarely ever heard of one happening on any make or model during my racing years. You can burn up your clutches through abuse, waste your top ends by not cleaning your filter, and trash hubs by not tightening spokes. I know people occasionally bust a tranny, but I know of way too many 00 Yamaha's that have done it and that's not acceptable.

daveyg (Honda bound)

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