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Could I have bent a valve?

3K views 3 replies 2 participants last post by  tylerlew89 
#1 ·
Please bare with me on the story here. I may have damaged a valve and want other peoples opinions. No idea how sensitive the valves might be.

So, my new to me '05 R6 has 27k miles on it...time for a valve clearance check. I dismantled the bike and got to the valves. Intake side is all in spec but exhaust is out on 4 valves. Time to get the exhaust camshaft out.

Here is where I ****ed up. Without checking to see if I had cylinder 1 at TDC, I went ahead and removed the cam chain tensioner. Before removing the camshaft I noticed wasn't at TDC on 1 so I went to turn the crank to get it there. I heard an odd noise which I thought was me kicking something at my feet but it turned out to be the chain slipping on the gear on the crankshaft. The chain slipped maybe 6-7 teeth. Without knowing it slipped yet, I tried to turn the crank shaft more by my wrench basically hit a hard stop. I didn't want to force anything so I stopped pretty quick. I assume here that I ran a cylinder head into a valve. I didn't put much pressure against my wrench. Only about as much is needed to make the thing turn over when there are no plugs installed.

I ended up removing the forward cam chain tensioner and that gave me enough slack to get the chain back where it was. Split mark on crankcase and marks on camshaft gears are spot on now. Engine turns back over smoothly with wrench and cam chain tensioner installed.

I went ahead to remove the valve shims and I am now waiting to get replacement shims tomorrow before putting the camshaft back in and getting the bike together again.

Can I get people's opinion on how ****ed they think I am or am not? Like I said, I didn't apply much pressure. I certainly didn't force anything after the chain slipped but I did have some resistance. Could this have totally bent a valve or ****ed up my valve seat?

Fingers crossed

thanks!
 
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#2 ·
My plan as of now is to continue the valve adjustment and perform a compression test when done. I didn't check compression before the adjustment but as long as all 4 cylinders are about the same then I will call it good.


Can anyone shed light on which valves i might have hit? When the chain slipped my timing gear was ~60 degrees CCW of TDC on cylinder 1 and the exhaust camshaft gear was about 30 degrees CCW of the engine case. This to me means that my #1 cylinder was probably at or near TDC while the cams were lagging behind. I think intake valves on number 1 are a candidate but don't know enough about the timing to know what else could have been in the way or in the way more than #1.

Thank again
 
#3 · (Edited)
If you were turning it by hand, chances are that you will be OK. But your plan to check compression is right on point. You need to do that to be sure.

If you were on the upstroke of the compression stroke for #1, then the intakes valves on that cylinder should have been closed, so #1 wouldn't be my first inclination. From what you described, #2 would have been on its intake stroke. But it is hard to know for sure where you were in the firing sequence, and ho much the chain really slipped, etc. Just check all cylinders.
 
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