TOPIC:

I need new cylinders and found a very low miles engine in this condition.  No compresion obviously, so obviously I don't know what condition the bores are in, so is this a complete waste of time to consider? I'm not sure what the stuck valves might mean for the condition of the cylinders, or if anything can be reliably assumed from it. I'm not even sure how it can turn over with stuck valves

If a valve is actually stuck, the crankshaft could not make a full revolution unless the head of the valve is broken off and bouncing around in the cylinder. I would pass unless I could get a bore scope in the cylinders to confirm their health.

I suppose it could be a sticky valve that is being pushed almost closed by the piston. I would still wqnt to look inside first.

Bent valves most likely.  Time to pull the head.

wrote:

Bent valves most likely.  Time to pull the head.


 

How do valves get bent on a low miles (<5000) bike? Neglect? Abuse? Don't really care about the valves but if it could indicate piston/bore problems, I care a lot

Abuse most likely, whether intentional or mistaken... down-shifting, instead of up-shifting gears at max RPM, 
 causing over-revving, whereby the resulting velocity / inertia of the valves is greater than the valve spring's ability to maintain the valves following the profile of the cam lobes, and out of eachothers way, and, out of the way of the pistons!

H.

Owner now says the intake valves do not move, so if it is truly turning over that must mean they are broken off.  Sounds like cylinder damage is likely too. Scratch another one from the dwindling list...