Super Jet Compression questiion

[Sjetfactory]

Except piston rings, cylinder, base and head gasket, what can drop compression on 1 cyl ? ( 105 - 155 ) 105 on the rear cylinder...

 

[ProSouth]

holy piston

 

[SJ 701X]

Is the piston cracked? Or a pin hole in it? Maybe the head is warped?

 

[Sjetfactory]

I fresh rebuild all engine, brand new piston and oversize , new ada head. After 3 rides I stop cuz I heard a little intermitent sizzling noise like a pressure in the carbs ( dont know how to discribe the little noise i heard ) I put the head out .. cyl out, there was lot of wear near exhaust port, but piston was a1. I rebuild up with gasket and stock head, I also pass the stones to refresh the cyl ... start up .. same noise, 5 or 10 lbs more compression on the same cylinder. same problem. It also crank slower when the gauge is on the low comp cyl.

 

[Sjetfactory]

cyl was looking like they drink water before I repass the stone ..

 

[Sjetfactory]

but I was not feeling like he drink some except the noise... it run well .. .. piston wash too on the low comp cyl

 

[TheBuzzard]

compression pressure is based on ring seal and head gasket seal, period. if one cyl is lower, its the ring seal, if everything is the exact same per side. squirt a little oil in the low cyl and do the test. if its up, its ring seal and i already know it is.