Hi, looking for some advice on an older Yamaha Breeze 125, I think they are the same as the Grizzly 125. Was running great, then used it to tow a small finish mower around and the load must have caused timing chain to slip? Did a compression test after it stopped and sure enough, 0. Took the head off and the intake valve had impacted and bent.

Sometimes when you fix a broken part and not the underlying cause, it's going to do it again, which I anticipated, but I bought a replacement valve for $15, and gave it a shot. Got the new valve in, lined up the timing chain per spec, re-installed the tensioner (looked good) and manually rotated the crank, no impact. Got the compression gauge out and cranked over the motor, good pressure; happy at this point. Put the plug back in and put everything back together. Fired it up and BAM, heard an impact and sure enough, compression test showed 30psi, assuming bent valve again. I assumed the bottom gear was stripped or some other issue, so I took the crankcase cover off and looked behind the chain case cover; everything looked normal.

Before I put any more time and money into this thing, was hoping to get some feedback and figure out what would be causing this? Do you think the chain is stretched out and under firing load it slips? The tensioner only clicked 4-5 times and chain feels tight. The guides look normal.



Thanks.