Recently swaped frames and noticed a crack in the motor casing extending about 3 inches along the center in a non-vital area, a couple of inches away from the exhaust port area. So, I had it welded and reinforced. After assembling everything and running it I noticed excessive vibration at low rpm especially at deceleration. It goes away at high rpms and there is no loss in power. Is it possible something in the crank case area got warped a bit? I could touch the head right after welding and it was a little warm so I don't think its the piston. Anyone got any ideas on what might have happened? Is there any plastic in the crank case that may have melted? Thanks

 

Hmmm...
And it didn't do it before I take it...[img]i/expressions/face-icon-small-confused.gif[/img]
No plastic or anything I know of. [img]i/expressions/face-icon-small-sad.gif[/img]
Rollers and bearings OK in the clutchs? Something come loose in there? keyway on the crank/clutch?

 

Thanks for the reply Jack. I rechecked the rollers and they are in position and fine. The key seems to be in the groove as I turn the variator side to side, it holds but that key does appear super small and worn and there is some play. I took apart the rear clutch and it seem okay. The worst vibration is at deceleration but low rpm is bad too. Any other ideas? Is there an easy way to replace the key? Thanks again.

 

we had a low vib in ours ended up being the rod bearing.also check the frame bushungs they some tiimes give vib also.