scott s
XS650 Guru
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, liberallysquirting 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.
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, liberallysquirting 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.
