This is my stock Zenoah G320 with an appropriate small engine compression tester. Just for reference as I have no idea where other brands or even other Zenoah engines usually fall compression wise. I've only checked this one so far.
will not start
definitely need a bore and new piston or new cylinderGreetings all: After 5 years of use it seems like my motor top end might be smoked. It"s a CY 23 in a FG Marder. I removed the engine to get a good look at it. I can spin the the flywheel with one finger. The engine spins all the way throught the compression stroke with almost no resistance.I was only getting about 60% or 70% power, which is what leads to to believe the ring or the cylinder is smoked. Anyway... I gues I'm just looking for someone to agree with my diagnosis. I can get a hold of a compresion tester l8tr this week if I need to. What number am I looking for? Guess I will go with a 35mm Big Bore kit. That should solve the problem
It's trash. New rings minimum depending in what the cylinder looks like.
120psi is minimum for most of them, some will still "run" at 90 psi. Yours looks like a well run in one. Not unusual to see 200+psi on a stock engine.
Pretty much the same as a saw or any hand held ope. I've had vintage saws run at 100 psi but they don't cut well.
The break-in is a moot point for your situation with the current engine unfortunately.
I just run mine and get the same results. Only thing I worry about "break in" is ringless engines.
I have no doubt you can get the same results. My point was, having been told that heat cycling is detrimental to performance because the rings never properly seat, is that it's false. At least if using full mineral oil to do the process I do. There's more than one way to skin a cat so to speak.
Not detrimental, just no point in it. Doesn't help a thing and based on myth..
just run it lifght does it look used exhaust soot
your compression is shot have you pulled off intake and exauhst to make sure theres no clogs but you definitley need new ringsmaybe a bore and hone
that is tru but you could bore and sleeve but thats more expensive then a top end i forgot there nickle plated
Impractical on small cylinders for years now. The few companies that did offer such services have basically ceased working in anything under a certain bore size. Cost factor alone, you'll have 4-5 times the cost of a new cylinder just haveing the old cylinder bored out, let alone getting a liner installed and port matched.
pretty much bikes are where it becomes cheaper these engines are just so cheap
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