Clutch or Gearbox problem ?

Hi All,

Two weeks ago the nut on the clutch boss came loose on my sons 05 YZ250F and tore the splines off the Hinson boss.

I replaced it with a standard Yamaha boss and since the rebuild it won't go into 5th gear.

You can select all gears with the engine not running but when the bike is moving it will not move to 5th.

Occasionally it will grind as though its half into gear (if that makes sense) but doe's not drive the bike.

Is this a gearbox problem or could it be something i did with the clutch ?

Regards.

Mike.

sounds like its a selecor fork/dogs issue. if it was the clutch i would expect all gears to be problematic

There could be a piece of metal in the shift segment or on the drum. I'd pull the clutch side cover first and look again for fragments.

sounds like its a selecor fork/dogs issue. if it was the clutch i would expect all gears to be problematic

Thanks for the reply feckless, will go with the easy option first and hope it's that.

There could be a piece of metal in the shift segment or on the drum. I'd pull the clutch side cover first and look again for fragments.

Thanks ronbuell, took the outer case off and plates out again, took long pushrod out and found it has snapped at the inside near the push lever shaft and can't get the small part out that is left in, any ideas how to remove this piece?

could this be the cause of it not shifting into 5th gear?

Regards.

Mike.

Oooo, well, you did find a problem. Is that the issue that's causing the shift issue? Not too sure. Seems I remember reading that someone else had the broken pushrod issue, but I can't remember how he got it out. You may be able to remove the push lever that the cable hooks to, and blow compressed air in there and force it out the shaft. Cover the end with a rag to catch it when it comes out. Worth a try.

As far as shifting into 5th, the only time I use the clutch is starting off. Once under way, I shift without the clutch. That's why when you said it wouldn't go into gear, I was thinking there is something blocking rotation on the shift shaft, or something with the clutch.

Now that you have the right side off, you might want to pull the left side as well, and pull the flywheel. Check in the sump for FOD (foreign object debris), check and clean the magnets on the flywheel, just give it a good inspection.

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