Transmission locked-up,but motor starts

5 replies to this topic
  • yam314

Posted November 29, 2009 - 08:44 AM


My Son was riding his 450f at an MX track yesterday,when the bike locked up after landing off of a jump.It will start,but the transmission is locked solid.
I suspect that he may have landed with his foot on the gearshifter lever,since it is bent downwards,and has a crack around the clamp that fits on the shaft.

I suppose that the shift fork may be bent? Is there something inside of the clutch case that may have broken that could be fixed w/o splitting the cases?
I plan on tearing into it today,and will post updates.

Does anyone have a good transmission for sale? The thing is,that I have a good 250f transmission in my garage,too bad it won't work!

  • l_campionero

Posted November 29, 2009 - 09:32 AM


Get it apart to see what's wrong before getting too concerned. It may be nothing more than the bent shift fork or a shaft.
Good luck!:banghead:

  • yam314

Posted November 29, 2009 - 03:59 PM


Well,I pulled the right-side case off,but did not see anything abnormal after pulling the clutch. So now, I guess it's case splitting time. I guess it's not too bad though for 200 hrs,and this is the 1'st big issue other than a valve job at 150 hrs.

The clutch shaft is stuck solid.Shifter shaft looks to be straight.I suppose the shifter drum is jammed,or forks bent.This sux!
Pulled the motor out.That thing is really wedged into that aluminum frame.The old steel framed YZF's were much easier to pull motors!

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  • grayracer513

Posted November 29, 2009 - 07:22 PM


If you pull the swing arm bolt completely out and drop the arm off the engine, it's somewhat simpler.

  • Geoffit

Posted November 29, 2009 - 07:30 PM


I agree the old bikes everything was better to work on! I have both for Supermoto and the 06 is up for sale it is a pain to work on.
The late tranys are pretty tough, look very carefully for cracks around the bearings in the case and the shift drum. the alloy parts can get beat up if the shafts get in a bind.
Send me a PM if you need trans parts ( not cases) I have a fair amount of complete transmissions as well as ind gears.

  • yam314

Posted December 09, 2009 - 09:02 AM


Well, I split the cases last night,and found one of the tabs broken off of the 3'rd gear.Looks like I will be replacing that gear as well as the one it meshes with.Also the shift fork has some wear marks,but doesn't appear bent,but it will be replaced too. The others look fine.I will also replace the cam chain,as well as all of the seals.Looks like it will cost around $150,which is much better than I expected.

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