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Discussion Starter · #1 ·
I have a '99 CBR 600F4. A spark plug blew out of the cylinder head a while back and I finally got my bike put back together again. I had it pulled apart and put back together once, but realized my timing was off and had to pull it apart again to fix the timing. Anyway it starts and idles fine, revs up fine, but there is a stupid amount of valvetrain nosie. Not just a little bit like it needs to warm up, but an excessive amount. Maybe i'm not getting oil pressure or something? Or maybe I didn't properly torques all the bolts? I made sure that all the shims were put back in the correct spot. Is there anyway that I can check for oil pressure? Or any other ideas why i'm getting so much noise?
 

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Lots of questions here Kinked...

First off... did the spark plug literally blow out of the head? If so... did you isolate the cause? What exactly did you do to repair the problem?

Second - when you say you realized the timing was off... did you realize this before you started, or attempted to start, the bike? Did you roll the engine over by hand - on both occasions - before starting to make sure there wasn't any obvious piston to valve contact?

Third - did you measure the valve clearances before and after your timing debaucle?
 

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Discussion Starter · #3 ·
the plug literally blew out of the head, striped the threads and all. I had a local shop put some kind of helicoil or some other kind of thread insert fix. I can't remember exactly what it was called though, but i'm pretty sure it was not a helicoil just something similar. I figured the cause of it to be someone over tightened the spark plug.

I realized the timing was off after I attempted to start it. I did not check for piston to valve contact, I was mostly praying that I didn't bend a valve. It seems to run well now minus the clacking noise. I figured that if i bent a valve, it would not seat properly against the head and would not run correctly. I did roll the engine over by hand, but was not specifically looking for piston to valve contact, but it seemed to turn over just fine.

I did not measure the valve clearances. I didn't have a feeling gauge at the time, and also had the valves professionally adjusted a few months before it happened.
 

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OK...

At a minimum, the first thing I'd do would be to pull the cylinder head cover and check all your valve clearances. Before you do, confirm that all the cam cover bolts are torqued correctly, and look for any obvious signs of trouble. If you did bend any valves (which is a possibility even if the bike does idle OK), you might be able to tell by the clearances on either the intake or exhaust valves being far off what's expected. But since you don't know the clearances to begin with... this may not yield any definitive proof. Still - it's something you can do with minimal investment in tooling, and no matter what I think you want to peek under the head cover if that's where the noise is coming from.

While you're at it - triple check your cam timing. And next time... ALWAYS turn the engine over by hand a few revolutions anytime you mess with the cam timing.

If I were working on it, I'd either run a compression test, or preferably, a leak-down test. The leakdown test would be much preferred, as any leaking valves would be easy to pinpoint. Don't know if you have the equipment.. if you don't, it's probably worth having it done anyway.

I don't know if there's any way you could have jammed a chain guide in wrong so it didn't allow the cam tensioner to fully extend - but have a look at the guides while you're in there, and the tensioner as well. Make sure that's all squared away.

I'm not saying you did bend a valve... but based on what you've said... it's a possibility you shouldn't ignore.
 
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