Pop, then lost most compression won't start now HELP

[gary55]

I know, so how do I fix it lol,

EDIT: I just redid the comp text now I have 23PSI?? This is weirding me out.

Well were losing comp. somewhere so what are our options.New rings, good head?, new head gasket, clean cyl.. So if was something allowing the cyl. comp. into the case the seals would have blown. The lose must be from above the piston. A unnoticed crack in the head, a stud backed or pulled out not allowing a good seal at the gasket. Somehow a leak through the plug.

 

[Street Ryderz]

yeah about a Half inch below, no hole in case piston exhaust is all stock standard and works perfectly. I just checked the spark plug threads they are fine and head thread is fine.

OK then what's the dia of the cylinder just above the top of the exhaust port?

 

[Street Ryderz]

How many time do you turn it over for comp check?

 

[FurryOnTheInside]

I would find the leaking compression with cigarette (not a flame if there's fuel in the engine, lol) if it's leaking out of the engine. If it isn't leaking out then it must be the rings.

You're doing the compression test correctly, I assume? WOT and pedalling until it isn't increasing further?

 

[StreetDemonCustomCycles]

Ive tried new head and cylinder, comp is now at 73psi, great improvement, I'm pedalling at least 15-20 times. Furry the piston rings are brand new arrived yesterday, 55.9mm from bottom of exhaust port to top of cylinder

 

[gary55]

Ive tried new head and cylinder, comp is now at 73psi, great improvement, I'm pedalling at least 15-20 times. Furry the piston rings are brand new arrived yesterday, 55.9mm from bottom of exhaust port to top of cylinder

55.9??? bulls**t. That would put the bottom of the exhaust lower than the top of the intake by 10mm +-.

 

[Street Ryderz]

Ive tried new head and cylinder, comp is now at 73psi, great improvement, I'm pedalling at least 15-20 times. Furry the piston rings are brand new arrived yesterday, 55.9mm from bottom of exhaust port to top of cylinder

Maybe the intake but not the exhaust and if it is you got real issues.

 

[StreetDemonCustomCycles]

Ive just taken off the intake port, and I've noticed a dirty great crack travelling up the cylinder wall, but is almost invisible when looking inside the cylinder like a hair. Thanks for all of your help guys!

 

[gary55]

And somehow the crack kept sealing it's self increasing comp. from 11 to 23 to 73. What a bunch of horse s**t.

 

[StreetDemonCustomCycles]

Excuse me son, I cannot explain this phenomena all I know is replacing the head, increased PSI, replacing the cylinder fixed it and put the PSI at 203psi, stock cylinder was cracked. thank you so much