something has gone horribly wrong piston hitting valve

[chuck hahn]

There is a 19MM aluminum nut and it has a 12MM steel nut in the center...what excatly stripped? The 12MM bolt that goes in to the crank? Or the crank theads themselves?

Re-time it, double check the repair done to the tensioner and reinstall it, re-adjust the valves then do a leakdown or a possibly a compression test looking for any bent valves.

Why did the tensioner need repair?

The tensioner had frozen up and the cam chain had slack in it.

That's what I figured had happened. And to think this all started with me trying to prevent it jumping time lol. Now my only problem is the rookie uh oh I made when it locked up. I tried to spin the motor with the 19 mm nut on the end of the crank and stripped not the nut but the threads.

[chuck hahn]

"they DID line up but now THEY DONT"...You answered your own question. At some point after restart, the tensioner caught and the timing jumped. Then, the tensinoer let loose and thats why the marks are off ...even though the chain is tight now.

[Steve]

It is rather common to install the tensioner incorrectly.

Almost everybody understands compressing the plunger, locking it in place, install the tensioner, release the plunger. What they seem to NOT understand is what happens next. After releasing the plunger, turn the setscrew in until it stops, turn it back out 1/4 turn and lock it in that position with the locknut.

Too many times I have seen tensioners that were locked in place, not allowing them to move and do their job.

.

[rustybronco]

Re-time it, double check the repair done to the tensioner and reinstall it, re-adjust the valves then do a leakdown or a possibly a compression test looking for any bent valves.

Why did the tensioner need repair?

[m.qualls89]

So I went to adjust my valves on my 1980 gs1100e. It has the lock nut and tappett screw so no shiming. I adjusted them all to spec which is .003"-.005" cold. Got it done fired it up and ran great. Then it started idling funny and choked itself out. Hit the starter just figuring it was cold, it spun a few times then CLANK! Locked up tight. Took it back apart and every valve would hit I'd loosen one up then the next would hit. I've loosened them all way up and they keep hitting even with a .016" clearance! But it almost looks as if it jumped time somehow which is odd as I just fixed the cam chain tensioner and all the marks lined up when I adjusted the valves but now they don't and the cam chain is tight. I'm stumped short of tearing the motor down what should I do.