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Discussion Starter · #1 ·
My buddy has a 1975 CB360T that's seized but it ran a few months ago and has been in a heated garage since. The back wheel turns freely but the kickstarter is frozen and when we tried to turn it over with a wrench on the alternator rotor bolt it wouldn't budge-jammed solid both directions. It seems like the pistons are stuck in the bores but could these symptoms indicate another problem like a broken and jammed cam chain or primary drive chain? Or?
Thanks in advance for your help!
Cheers.
Ross
 

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Might be stuck rings. Put the motor in 2nd gear and rock the bike back and forth. You might try pulling the plugs and putting a half and half mixture of ATF and diesel fuel in the cylinders or some other break free. Dont use WD 40 its more of a lubricant. You may have to let it soak for a couple of weeks. May not be the rings but if it ran when you parked it I cant see any thing breaking while it was sitting still.

Just my thoughts.

Bill H
 

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Seized is seized, no matter why or how bad. I have seen them stick starved for oil because the horrid black plastic cam chain tensioner (several recalls) disintegrated into small particles that eventually blocked the oil flow. The pickup before the pump is a fine mesh screen so this isn't too hard to do. The camshaft probably goes first as it is further away from the oil pump than any other critical moving part; it runs on plain bearing surfaces machined directly into the cylinder head, so it could also need a new head. After that it's pistons/rings/bore. Just have to take the top end apart and see what you've got, but be prepared for the bottom end while you're at it. Unless you are lucky.
 

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Discussion Starter · #5 ·
Thanks everyone for your replies! Pulled the head after cutting the cam chain and found one piston rusted to the barrel for about 2/3rds of the circumference...Only a tiny bit of water but it had seized solid. With the help of a large hammer and block of wood we drove the piston out of the barrel. Don't know what we would have done if both pistons were seized! The bore had some rust on it but I scraped it off with a razor blade and cannot see or feel any putting from it and there was absolutely no ridge (17k miles)! My intention now is to hone the cylinders with a ball hone, install new rings, cam chain, guide etc and inspect and lap the valves before reassembly. Wish me luck with the rings!
Cheers.
Ross
 

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Be careful lapping the valves they have a very light coating of hard material on them that can be lapped off. They were made to be replaced not ground but can be lightly lapped if thats all you need.

Bill H
 
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