2002 Yamaha yz426F slipping in only 5th gear

Riding my 2002 Yamaha yz426F today and riding it pretty hard on payment back roads and noticed after about 30 minutes after riding it some what hard finally after hitting 5th gear I noticed the bike wants to slip like a slipping clutch would fill like but it slips then catches and slips in and out of 5th gear and all other gears have no problem when shifting threw 1st through 4th only 5th today do I need to break out service manual and adjust my clutch are is there something else that could be going on besides the clutch please any advice are suggestions would extremely help me out open for any thoughts are suggestions thinks will be waiting for response and some advice .


Not a jetting question ??


You have most likely a shift drum or shift fork that is not pushing 5th gear all the way in position, or, the shift dogs on that gear are going/gone


 A clutch slip is smooth and consistent, so it is not the clutch.

If the "slipping" is jerky and rough, it's 5th gear on the main shaft pushing the third gear and the shift fork away from it due to wear at the locking lugs on the sides of the gears.  The fork will be bent, also.

Thanks very much for the feed back and advice it is a smooth and consistent pull are jerk so before I go tearing into the transmission im going to properly adjust the clutch before I go any farther into spitting case's are buying gears if the clutch adjustments don't work then I'll tear into the gears and inspect the shift drum forks and all gears im hoping this is not the big problem thanks again for the advice.

A smooth increase in RPM when loaded, as if the tire were spinning, would be the clutch.  5th gear operation puts a greater load on the clutch than lower gears do due to the fact that it's harder to drive higher gear ratios.

Think I solved the problem the clutch cable was way out of factory spec's adjusted bothering positions and bike will not slip now in 5th gear im just glad this worked rather then it being something to do with the transmission thanks again for the advice most helpful thanks.

Turning a Yamaha yz426F 2002 into a flat tracker need help please need to know how to way lower both front and rear suspension to meet flat track standards need to lower bike bad im only 5'6 and also right kind of wheels and tires that AMERICA MOTORCYCLE ASSOCIATION WOULD check off in there rule book as a sound and complete ready to go flat tracker.

This should have been posted as a new topic, as it's a change of subject.


You will need to  lace a 19" rim on the front, and remove the complete front brake.  I don't have specific tire info, though.  These days, there are specialty dirt track tires available just for that purpose. 


The best way to lower the fork and shock is internally.  On the fork, the best thing is to relocate the spring seats farther down the cartridge (assuming you still have the '02 fork), then add a spacer to the damper rod so that the for tops out sooner.  Cutting springs is sometimes done, but the thing to remember is that cutting a coil spring shorter makes it stiffer, so if you follow that path, you'll want to start with lighter springs.  You'll still need the topping spacer.


In the rear, just add an internal top out spacer and adjust the spring preload down farther.

Ok that sounds exactly what I was looking for and the right answers I was needing thanks a bunch Grayracer513.

So does the 426 have tranny issues or will it?

It depends on how they're ridden.  Nice clean shifts using the clutch or backing off the gas to shift will have them last just about forever.  Slop shifting or spending lots of time in 5th can result in a problem of skipping out of gear under a load.

So would making it a street bike, motard style, would staying if 5th still be an issue?

I don't see why it should, but some people who run the bike that way run into this problem and then blame it on road use.  The foundation for that assumption seems a little shakey.

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