Hi Everyone,

I purchased a 2007 Grizzly 660 that had been drowned. It ran but smoked something awful.

I flushed the oil, pull the head and cylinder. Replaced the piston rings. The piston and cylinder looked great.

The middle intake valve was bent, my initial guess was the motor was hydrolocked. The head looked great. I replaced all the valves and springs. New gaskets and reinstalled everything. Started it up and it smoked pretty bad, ran it for 5 minutes and then it quit running. I tore it back down and the timing chain had came off the crank sprocket. The new center intake valve was bent and had a shinny spot across the valve. I did adjust the valve prior to starting.

Any thoughts or comments would be appreciated.

Thanks,
Trent

 

Only a few ways this can happen.

#1 Over rev. The spring can't yank the valve back fast enough and the valve tags the piston.

#2 The cam timing was off or got off somehow.

#3 This just happened to the race car I crew chief for three weeks ago. A brand new head and the machinest got the valve to guide clearance too tight on one of the valves. The valve galled and hung up every once in a while. The piston came up and wacked the valve. Boom, bent valve.

I see no way a valve can bend if hydrolocked. Unless someone can explain how that can happen, I don't think it can.

It's going to be one of those three.

 

usually when stuff hydolocks the bottom-end/rod/piston is what gets messed up,the valves are usually shut and supported when the engine is trying to COMPRESS the water , thus the rod gets bent or something, but from all that pressure inside the engine and the water being there also it is possible to bend a valve but i dont think its likely also...in my experience with motorcycles its usually from something with timing...