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Px
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My px recently cut out on me..I couldn't get it restarted..I tried a new cdi but still no joy..I then stripped the barrel and head and found the top ring to be stuck in tight..Could this be the reason why it won't start..I had a good spark and fuel flow.?..
Thanks.
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@geeklion avatar
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top ring stuck tight? did it seize?
OP
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Not too sure..just cut out on me and wouldn't start again..checked the piston today and its OK but rings done in.
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When the ring is stuck, almost always it is a piston problem, often from overheating, occasionally from inadequate oil.

I assume with the ring stuck it has almost no compression, which would make it difficult to start.

How worn is your cylinder? Probably worth checking top and bottom dimensions to see if there is significant 'taper'. As well as piston side-clearance. I'm guessing you are going to find excessive clearance, which results in piston 'rocking' which breaks the ring seal, which overheats the ring and piston from blowby.

If one is available, perhaps time for an overbore and a new piston and ring. Otherwise a new cylinder, piston, and ring.

Might be able to scrape enough metal from the edge of the ring groove that a new ring will move freely. But it will be a temporary solution, at best.
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@mjrally avatar
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Stock piston with the rings stuck could be two things. 1. The rings have gummed up from fuel/oil and you can soak them free and reuse.

2. Or, its seized. Look for vertical scratch marks on the piston and cylinder.

Got any pictures you can share?
OP
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Rings snapped when I tried to release them.so gonna strip and replace piston and rings and also check for air leaks.
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79 P200E (Ruby), 62 Allstate (B-62)
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GIBBO01 wrote:
Rings snapped when I tried to release them.so gonna strip and replace piston and rings and also check for air leaks.
Sounds like a good plan. Is your piston scarred up? How's the cylinder look?
OP
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Barrell looks good but pistons well burnt and a few scuffs.
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79 P200E (Ruby), 62 Allstate (B-62)
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GIBBO01 wrote:
Barrell looks good but pistons well burnt and a few scuffs.
Hey Gibb - If you replace the piston, you might as well replace the wrist pin bearing. It's cheap insurance. The old one may look fine, but you never know.

And BTW, Welcome to MV!
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Got that in the plan m8..cheers..thanks for the replys.
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