YZ250 gearbox problem, still here!!! >:(

So here's the background, I rebuilt a YZ250J for a mate after someone else bodged it up (fitted wrong water pump seals, fitted piston backwards stripped threads, cracked cases.... :p

Anyway, the main problem apart from the piston & resulting broken rings was that when it did run third gear wouldn't engage. First thing I did was check for stripped gears/bent forks etc as it was apart anyway but nothing, next was to install a new shift shaft (original had stripped splines & was bodged together with no way of moving pedal position, pedal was hitting sprocket so I thought probably just not enough pedal travel to put it all the way in gear). So I put the motor back together again & rode it today & it runs nice & strong with no water in the 'box :moon: but still it won't engage third gear :busted: All that happens is it sits & grinds like with a stripped cog or not properly engaged, all other gears work fine. It feels like the drum is going in right & waggling the lever just either procures 4th or 2nd.

Anyone had similar issues with 3rd on their YZ & if so what was the problem? I'm running out of ideas & patience with this bike now so any suggestions would be cool, cheers. Dan.

EDIT-: also if anyone's got a pdf parts book or manual that covers the box I'd appreciate a copy of that to see if the last "mechanic" didn't lose a thrust washer or similar, although I'd doubt that as other gears are good I'd still like to eliminate it.

EDIT 2-:Just found a parts book & there's a possibility that there may be some thrust washers missing if the cluster's been apart, which I don't think it has. Other than that though I'm still stumped... Going to pull engine out again now anyhow, it's gotta be done...

did you check the dogs for wear?

Cheers for the reply.

Yep, all seemed good. I will be stripping it down soon (not many other options really!) to have a closer look & find out what the hell's going on.

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