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Discussion Starter #1
Posted before but now have a new problem- my husband got his bike running and idling good finally but then it made a grinding sound that he described like something got stuck in some gears. So he turned the crank shaft while I was recording inside the valves and one of them wasn't opening at all. He was thinking it's a possibility when his buddy was helping him he could have knocked something in it, that's why we were checking out the valves. Doesn't know for sure though. Any ideas on why or how to fix it?? Thanks!
 

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Is the diagnosis correct? How could you or your hubby see that one valve wasn't opening? That could only happen if a valve stem was broken, and that would have made hell of a racket when it happened.

What I am wondering now is that after previous works if the cam chain tensioner was incorrectly fitted/adjusted and the cam chain has now slipped (hence the 'grinding' noise).

What state is the bike in. Is the tank/airbox etc removed so you have access to the motor?
 

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Discussion Starter #4
Just adding- it's the first one- seems grimier too. The 2nd seemed not to move but went back to it and it was fine. Back the 1st and- nothing.
 

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Not sure if it's photographic distortion, but the second valve actually looks bent (at the base) and also looks unseated at the left edge.

Further, the number one inlet ports show a lot of discolouration which appears to be carbon blow back from the exhaust valves being open. Whislt there is usually some overlap with valve openings, the discolouration really suggests a valve problem. I now wonder if the camshaft has actually snapped, or the buckets/shims out of place.

Perhaps wait for further opinions, but if the bike were mine, I would be doing an immediate valve cover and possibly top end removal to see first-hand. No matter what, there is some serious damage in there (in my opinion).
 

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A compression test would be ideal, but from the video I agree with Nigel. Cylinder # 1 has major issues. I didn’t see either valve move, they’re extremely dirty and wet, and the port is a mess.

Time to drop the motor it and take the “top end” apart. Remove the valve cover, camshafts etc and inspect everything for damage. Missing keepers or a broken valve is likely.

Didn’t you originally have a shifting issue with his bike? This escalated quickly :thumbd:
 
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