Tristan
XS650 Member
Hi guys.
I’m helping out rebuilding the engine of a friends ‘74 tx650.
Before teardown the bike had various oil leaks, a bodged oil feed pipe to top of engine (see pics) Right hand cylinder running fine, plug looks good. Left side, poor running, popping exhaust, oil coming out of exhaust and oil on plug.
My fears were that bodged pipe had over the years effected top end oil flow and I was correct in my findings.
Cam has pretty bad wear, see lip in pic and rockers have some serious flat spots.
I’ve not had the valves out but I imagine that lack of lubrication has buggered up the valve guides too, hence the oil leak.
I didn’t do a compression test, 1. Because I was pretty sure of the culprit and 2. Half the spark thread on that side is mullered (unloved engine) so I couldn’t anyway with the shorter than plug thread attachment.
Ok so I’ll prob have to find good cam/rockers /valve job.
Next onto the pistons. Bores don’t look too bad, very light scoring that can’t be felt with fingernail and even where the piston hasn’t made contact at the wear line I feel no ridge.
What does concern me is the bottom end of the barrel. Piston walls have blackened and also seemed to have left aluminium deposits to cylinder. This is in the bad side.
Any idea what would cause this? Over heating that side maybe?
My next thought is to hone the cylinders, then check piston wall clearance and then clearance with new standard size rings (if I can borrow them)
Otherwise the bills are gonna go crazy with the re-bored and new pistons too!
Also I noticed that one of the dowel pins was missing on the cylinder to block. Are these just locating or would this effect oil flow too?
Thanks for any advice.
I’m helping out rebuilding the engine of a friends ‘74 tx650.
Before teardown the bike had various oil leaks, a bodged oil feed pipe to top of engine (see pics) Right hand cylinder running fine, plug looks good. Left side, poor running, popping exhaust, oil coming out of exhaust and oil on plug.
My fears were that bodged pipe had over the years effected top end oil flow and I was correct in my findings.
Cam has pretty bad wear, see lip in pic and rockers have some serious flat spots.
I’ve not had the valves out but I imagine that lack of lubrication has buggered up the valve guides too, hence the oil leak.
I didn’t do a compression test, 1. Because I was pretty sure of the culprit and 2. Half the spark thread on that side is mullered (unloved engine) so I couldn’t anyway with the shorter than plug thread attachment.
Ok so I’ll prob have to find good cam/rockers /valve job.
Next onto the pistons. Bores don’t look too bad, very light scoring that can’t be felt with fingernail and even where the piston hasn’t made contact at the wear line I feel no ridge.
What does concern me is the bottom end of the barrel. Piston walls have blackened and also seemed to have left aluminium deposits to cylinder. This is in the bad side.
Any idea what would cause this? Over heating that side maybe?
My next thought is to hone the cylinders, then check piston wall clearance and then clearance with new standard size rings (if I can borrow them)
Otherwise the bills are gonna go crazy with the re-bored and new pistons too!
Also I noticed that one of the dowel pins was missing on the cylinder to block. Are these just locating or would this effect oil flow too?
Thanks for any advice.
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