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Noticed a leak at the front cylinder last Sunday. Decided to tear down the top end today - found out previous owner didn't even have a gasket between the front cylinder and head which explains the leak. Was relieved it wasn't something serious. I have been burning oil since I bought it 3 years ago so decided to do some investigating. Thought maybe just needed new rings but the pistons look good (I think) and the cylinders look great. What do you think is causing my oil burn from the pics? Maybe valve job? This is my first time tearing down a motor like this - all input is appreciated!
Based on the pics I would redo the top end. The marks in the bore, its shiny with no crosshatching and if there was no head gasket I would be shocked if they guy put guide seals on it.
I ran many years an iron head pro gas race bike with no head gasket BUT we used red loc tite for the iron head to iron jug for sealing
have a hachine shop do both as said and use the rubber valve stem seals not the tin china copy’s today
the front connecting rod tells the story of flywheel life — with the piston removed - and the front rod at TDC - see if you can twist it from left to right
a small amount is fine - if you do have movement film it and re post - the movement is the wear on the rollers - the races in the rods and the crank pin
Last edited by johnjzjz; Jan 27, 2025 at 06:50 AM.
Based on the pics I would redo the top end. The marks in the bore, its shiny with no crosshatching and if there was no head gasket I would be shocked if they guy put guide seals on it.
The more I looked at it the more you're right. There was no more cross hatching with mainly vertical scoring.
I have a guy lined up already for a top end rebuild. Gonna take it in next weekend.
Stupid question but I obviously the fix will take care of burning oil but what kind of performance improvements can I expect on a fresh top end?
I ran many years an iron head pro gas race bike with no head gasket BUT we used red loc tite for the iron head to iron jug for sealing
have a hachine shop do both as said and use the rubber valve stem seals not the tin china copys today
the front connecting rod tells the story of flywheel life with the piston removed - and the front rod at TDC - see if you can twist it from left to right
a small amount is fine - if you do have movement film it and re post - the movement is the wear on the rollers - the races in the rods and the crank pin
I hear ya but the head came loose with MINIMAL effort. He didn't run anything between the head and cylinder. I'm surprised it took this long to start leaking to be honest.
You would see a bigger gain with a cam change than a top end refresh if it was running okay other than oil consumption. Im sure you'll feel it but you wont be blown away by the improvement.
You would see a bigger gain with a cam change than a top end refresh if it was running okay other than oil consumption. Im sure you'll feel it but you wont be blown away by the improvement.
I could be wrong but I thought an AB was good for a doorstop. I have an Andrews BH (h for hydraulic) in my 82 80" with higher compression and Im happy with how it works but some will crap all over the B I think?
I could be wrong but I thought an AB was good for a doorstop. I have an Andrews BH (h for hydraulic) in my 82 80" with higher compression and Im happy with how it works but some will crap all over the B I think?
Sorry - meant Andrews A cam.
Originally Posted by 1981 suprglide
I may be wrong, but it looks like a gasket is on it get a screwdriver see if one is on that
There was a gasket on the rear jug - nothing on the front jug.
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New Valves?
