Messages

1

Technical / Strange crank problem

« on: February 11, 2013, 06:10:05 PM »

Thanks for the input, guys.

I suspect that when I finish tearing it down, I will find really worn main bearings. I probably let that bottom end rattle I've been hearing for a year or so go too long. The bearing may have seized causing the race to spin on the shaft or just got beat hard and long enough to loosen and wear.

Good to hear it's not an isolated thing. I bought the motor used so don't know it's history but it appeared low hour and had no tool marks on any of the nuts or bolts.

If I find anything of interest when I get it apart I'll let y'all know.

I'm gonna replace the crank and mains with OE parts and send my top end to Eric Gore for the 295 treatment.

2

Technical / Strange crank problem

« on: February 10, 2013, 05:39:25 PM »

I've had a wet side main seal leak on my 03 YZ250 so I tore into it to replace the seal. I got the seal out and there's noticealbe play but it's not in the bearing - it's between the crank's shaft and inner bearing race. If I put a finger on the inner race it spins on the crankshaft.

I suppose the reason for the bad seal is this movement... It seem odd to me though. Shouldn't this be a tight or at least very snug fit?

Crank is tight but if I'm splitting the cases I might as well give it a complete rebuild. Just wondering about this movement. Anyone else see such a thing? I'd like to figure out why this happened. Bad main bearings beating the race to death perhaps?