Topic: XS650 diagnostic help needed (valvetrain and/or oiling issue?)

[Scott S]

 Engine is a 1978 XS650. Top end was redone approx. 700 miles ago to replace a head with broken fins. Everything was bead blasted and reassembled with fresh gaskets and an overbore on the pistons. All work was done from the case up. The head was a "good" head from ebay. The cam was reused.

 This engine has been noisy since day one. At first, I thought it was the cam chain and/or valve noise from after the rebuild. Adjusted both at ~100 miles and again at 600 miles. I also re-torqued the head. Timing is spot on. No weird clearances noticed at either valve adjustment. Cam chain needed no adjustment at 600 miles.

 Still....the engine sounds noisy, like a valve or valves are out of adjustment. It comes and goes, but I can't relate it to any one thing. I.E., cold oil at start up, warm oil, RPM's, etc. I just know that I've owned enough XS's to know it isn't right.

 The screwdriver to the ear trick doesn't narrow anything down. Neither does a mechanics stethoscope. I replaced a couple of the copper crush washers on top pf the head at 600 miles and there was oil on top of the head, so I think I'm getting oil up there.
 I didn't notice anything unusal during the valve adjustments. Everything seemed to be getting oil and not dry.

 The bike runs (well....RAN) strong with no issues other than the noise. I rode it for ~60 miles the other day and it was fine. Parked it for an hour and on the ride home I noticed it was running rough and didn't seem to want to rev. If I kept it below ~3,000-3,500, it was OK. Beyond that, not smooth and wasn't right.

 I suspect an oiling issues has:

A) Caused the cam to wear and I'm no longer getting proper lift, or...
B) It was starting to sieze up. However, heat shouldn't have been a factor and the cylinders are oiled differently than the head, right?

 I plan on removing the valve covers, liberally squirting oil all over the adjusters, valves stems, etc., and see if it seems more quiet. I will then drain the oil and check for debris.
 An autopsy is probably in order, but what am I looking for? I really can't seem to trace it to any particular place.
 Any other ideas on tracing the oiling? From the oil pump up to the head, how do I determine if that's a part of the problem?

[grcamna2]

I have a question about the integrity of the cylinder Head from Ebay..did you have it checked out before installing it..the valve seats & guides ? I think if the valve guides were worn badly it could cause this..or possibly your camchain tensioner having troubles..  How loud does it get ?

[Scott S]

 It sounds like a valve is out of adjustment. Just a ticking or tapping, even when all the valves are set correctly.

[grcamna2]

If you feel that the engine is reasonably well "broken in" at 700 miles it'd be good to either do a leak down test or a compression test after you brought the engine up to full operating temp.Do a few of them during the space of a 1/2 hr. and see if the results vary from one time to another..to possibly determine if the valve seats or guides are worn;the valves can move around quite a bit in a worn guide & seal differently at different times. The head seemed OK visually before you installed it ?