ALL This Jetting talk...................

Can I just buy a 2002 WR426 and not worry about changing Jets. I live at 4000 FT but also go to sea level about 30% of the time. It bothers me to spend $6000 and have to start tinkerin right off the bat. I'm concerned about this subject. I don't have any carberator experience at all. Will she start and run good for me ????? :)


I'm in the same boat, I also do not have alot of carb experience. But, after reading my manual and all the jetting posts here on TT. I have changed my timing, deoctopused my carb and yes started jetting. And since then my bike has really started to scream. Its good experience to get to know your bike, you can spend alot of money at the dealer and the goons in the back dont know any more than you. But they will take your money if you are not educated. Just my 2 cents

Pete :)

I bought a WR a couple of years ago...I had to rejet the really isn't that hard. I do have some carb experience. Just don't be a big armed ape about it. It is fragile. I know the replacement cost is about $900.00 maybe less maybe more. There are alot of well experience guys on this forum who are willing to help you. Maybe you can find someone with the exact same conditions and bike setup, so you only have to do it once. Go through the archives, there are tons and tons of jetting answers. Half of owning a bike is maintaining it (some times it feels like I spend more time maintianing than riding I am a little anal) There are some great smaller non-dealer mechanics that know there stuff it just takes a while to find the 'right' one. :) I found one of those guys here in Tucson...he works out of a house! He had a poster of a YZ426 on his wall I knew I found the right guy. Ask around your local riding buddys and maybe see if anyone from this forum is in your neck of the woods. They might know a good mechanic if you don't feel up to doing it yourself. Oh yeah remember to tear down the bike and grease all moving parts and bolts. Some bolts I grease others I locktite.

[ May 05, 2002: Message edited by: Kermit ]

It's a race bike with a race carb, not fuel injected...jetting is part of it. Keep in mind everyone here is tweeking for more power, crisper response, etc. The bike you buy should start and run good for your location when you leave the shop. And certainly will run stronger than any XR400, but the XR has a more user friendly carb (read: NOT a race carb.) Until fuel injection is perfected, jetting will always be part of ANY bike you buy IF you're looking for the MOST power out of it.

Noone wants to fiddle with their $6000 new bike, but eventually you'll find the time and the knowledge to tackle it. As Kermit said, it's not that hard.

I have been there and done that with all the jetting, cam timing etc and have come to the conclusion that for what I ride almost stock is best. I found most of the mods do generate more power but the bike became a little too much like a motorcross bike with a big top end. I like the stock WRs bottom end and mid range. Great for enduros, trail riding, hills etc. Plus high revs lead to more wear. All I have now done is run a Staintune pipe (not loud but better than stock pipe) and have raised the needle one spot. I havent found a 400 faster than mine...

The starting issue is a myth. Buy a bike with a happy button if you want easier starting.

The people at Yamaha dont spend millions of R and D dollars to produce a dud bike. Just buy it and ride it. They are the biggest selling bike in Australia for a reason.


I have a 2001 WR426 that I run completely stock except for the gray wire cut and throttle stop cut. The air box lid is on, the pipe insert is in. It runs great and has all the power I need. All I do is trail ride - no racing.

I have played with the jetting and muffler (took insert out, tried some different tips, ran some sound meter checks - too damn loud!) but wound up putting it back as stock.

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