Head noise diagnosis help??

[newmaac]

Hey listers,
I am in search of a little advice. Let me start with some background info.
1980 SG with about 54,000 miles.
Cleaned and adjusted the carbs, adjusted the cam chain tensioner and valves in May. (less than a thousand miles ago)
Overall the bike is in good shape and has given no mechanical grief.

While riding home from a camping trip, I got stuck in a MAJOR traffic snarl. Not wanting to split lanes with the saddlebags and camping gear, I sat idling much longer than I normally would.
I heated-up the motor pretty badly. It actually started detonating a little before I made my way to the shoulder to pass the stopped traffic.

Ever since then, I have had a slight noise up in the top of the head. (at least that is where I suspect it to be coming from).

Last night, I loaned the bike to my son, who I imagine might tend to push a little harder than I do. (that was a sarcastic understatement)

This morning when I went to warm it up before work I found the noise to be MUCH louder, kinda like a rattling sound.
I am thinking that I am hearing something in the cam chain, maybe a warn guide or the tensioner???

Before I do some expolatory surgury, is there anything that you you can think of where I might start?

It is a rattle, (kind of)
It doesn't sound like valve noise,
It is not detonation,
Oil level is good.

Any suggestions appreciated.

[trbig]

I'd do a compression check first and see if all the cylinders match up, or if you have one out of synch with the others. If you get an odd reading, you can start tracking it from there. 2nd, I'd go to an auto parts store and get an automotive stethoscope and try to track down exactly where the noise was coming from before surgery... could be as simple as a leaky exhaust gasket. 3rd, I'd quit letting a heavy handed son ride my bike that had a weird engine noise! lol.


Tod

[prometheus578]

Valve clearances shouldn't change. Quick check would be to redo the cam chain tension. Those are the only two adjustments that you can make. I can't see how the cam chain would get loopy all of a sudden,(by overheating) but the tensioner could have slipped.
If that doesn't remedy the situation, get a cheap mechanic's stethoscope and try to pinpoint the noisy area.
I sat in traffic once till my pipes' glowed. Pulled over and shut it down. It wouldn't crank again till the engine cooled down.
That was 20,000 miles ago... no damage.
Knocking, especially after running hot, is not a good sign.
Get a clean pan and drain the oil... see what comes out. Hopefully, not little, shiney metal peices.

[mro]

in heat, call your vet

Over heating can do several things

1) oil can break down
2) valve(s) can get damaged also valve seat can come loose from head.
3) piston(s) can hit cylinder, or a bearing can go south
4) warp head (have not seen/heard this on an XS

________
Noise getting louder??............. piston or bearing my guess



mro
btw
hear it at idle?? louder under load???

[newmaac]

OK, I just know that many of you have not been sleeping well, knowing that I had not found the source of my "head noise".
So, I am going to take care of that for you.

Tonight "Diver Ray" stopped-by on his way home from work to "have a listen".
Being pessamistic, I was envisioning major damage to one of the cam chain guides or something. I had pretty much determined that the noise was coming from the chain.
After about ten seconds of hearing the motor, Ray asked, "Well, did you try adjusting the chain?"
I had adjusted it back in May, so I didn't think that it would get outa whack THAT quickly, so, No I didn't even check that.
5 minutes later, and viola!!!

Cudos for Ray, (Duh for me)

Thanks, Ray


Mike