96 robin 4 stroke "no compression"

[Big T]

I bought a 96 ez go cart from a friend with a slung rod. I picked up all rebuild parts from my local dealer. I assembled the motor without any problems....so I thought. The problem is I only have 30psi compression. Everything on the engine is good as far as cylinders required very little honing, head looks fine, installed new intake valves cleaned and lapped exhaust valves. What could I be missing? I just built a 99 GM 350 complete so it's not a matter of I don't know what I'm doing....or is it? I'm a bit frustrated.

[rusty shackel]

what is the ring gap ? did you try to start it ? the walls might be dry add a little oil directly in the spark plug hole then try.

rusty s

[Big T]

I did all of that. I think the rings might be wrong

[victorjohn]

If you honed it, you practically oversized it. Use bigger rings.

[Cheezygo]

How is the camshaft timed on your engine? Is it correct?

[Dave Box]

Tell us exactly what you did. Did you simply put new rings on old pistons in an old cylinder? There are many reasons why honing doesn't work so if that is what you did that is probably where your problem lies. Did you do what Rusty Shackel suggested, if so what were the before and after numbers?

[Big T]

Yes I did what he suggested. I will need to go back and record the measurement. I used the same piston in the same cylinder. The cylinder walls are not warped or anything. When I honed it it was merely for scuffing only. I didn't have a ball hone. I don't believe that the honing is an issue. While I had the head off I put some WD-40 on the top of the cylinder and within five minutes or so it was gone. I have double checked the orientation of rings and they are all right.

[Subarumouse]

Hello Big T,

Balanceaxle and cranck are with the marks together?

The onley other possibillity could be stuck or broken rings or bent valves.
Onley this can almost not cause problems on both cylinders.

I am gong for the timing of the balanceaxle.

Benno

[Big T]

I checked that twice. When I couldn't get it to start I thought the same thing but it was fine. The valves are good as well I lapped the old valves and the new valves. It puts most of the compression into crankcase. Thanks for reply

[BLUE72CAMARO]

Originally Posted by Big T

I checked that twice. When I couldn't get it to start I thought the same thing but it was fine. The valves are good as well I lapped the old valves and the new valves. It puts most of the compression into crankcase. Thanks for reply

IF its putting the compression into the crankcase the problem is in your rings. Past them is the only way you pressurize the crank case.