CYLINDER REPLACED AND NOW NO COMPRESSION !

[hexbeatz]

ye i swapped piston out of the exact same bike, also the bike started before i took it apart and now compression is just gone, one thing i do know is, i left the cylinder head out in the rain so valves would of get wet, but weren't wet when i attached it all back together

[Zorge]

What to say?

[ChrisFraser]

Hi,
Some things to check and think about.

Correct cylinder fitted, correct gaskets used, correct piston and piston rings ok and fitted correctly correct orientation correct gap correct order this assuming more than one ring , valves working IE not sticking open, spark plug fitted and tight, if these things are correct then its a puzzle you should have compression. If all is correct and you have the timing correct when you turn the engine over there should be compression. let us know how you get on.

[hexbeatz]

It was the spark plug mate it had a brand new one in put the old one in and fired up first time lol

[ChrisFraser]

Well that's great news. your compression must have been fine just a duff plug, Ive had a couple of new plugs over the years that are no use.