lost all compression

sneekypete

sneekypete

New Member
Bike was running fine this morning but now it rolls with the clutch out and won't fire.. I was trying to get the motor to idle, messing with choke and fuel mixture screw and it started doing that... Any help please!!!-!
 
Any sign of leakage at the cylinder head? The head bolts need to be torqued initially and after several heat cool cycles. You might want to remove the cylinder head and inspect the gasket. If it isn't damaged you can reuse it and tighten the head bolts to 120 to 140 inch pounds. Those chrome acorn nuts are pretty but can cause problems. We suggest replacing them with shouldered/flanged hex nuts. The acorn nuts can bottom out before tightening against the head causing loss of compression.

Some kit instructions will tell you to "finger tighten the spark plug". That is very very wrong. It should be torqued to 60 to 80 inch pounds. A loose plug can also be the source of compression loss.

Buy, beg, borrow or steal (no, don't steal one) a good inch pound torque wrench. It will pay for itself compared to the damage you can do by overtightening fasteners.

There probably is no fuel mix screw on your kit carburetor. It is just an idle speed screw which I explained in your other thread.

Tom
 
sounds like something went wrong with your clutch (maybe fuel spilled into it?)

open & look for wetness in there, clean if needed and then go thru the cable/clutch adjustments
 
I didn't see his other thread Tom. I just read that it just rolls and won't kick. If he really lost compression, it's time to take the cylinder off and check for a stuck ring or bad head gasket..
Did he do a compression check?
 
Easy Rider said:
I didn't see his other thread Tom. I just read that it just rolls and won't kick. If he really lost compression, it's time to take the cylinder off and check for a stuck ring or bad head gasket..
Did he do a compression check?
Click to expand...
He has another problem and posted it earlier today. It's in this (troubleshooting) section too.
We haven't heard back from him yet but a compression test would tell us a lot.
Thanks for your help, ER.

Tom
 
Just got home from work... I tightened the head bolts and opened the clutch plate and the sproket nut was a little loose.. I tightened it and took the little metal shaft out in the center of the sprocket with my fingers and it seemed a little wet and dark.. I didn't clean it and gave it a shot, no change.. It still rolls with the clutch out.. It's a new build, used 5:1 ratio in the tank, and I didn't hot rod it at all.. Thanks for the responses, by the way!!!
 
the bar needs to be heavily greased, but does not cause the clutch to slip on the other side of the motor - look over there & follow adjustment steps on the board here

was 5:1 a typo? I've never heard of anyone doing that - 16:1 is about the most one should use, while 32:1 is common after a tank or so
 
Sorry, I meant 5oz to a gallon-- actually a little less than a gallon.. It seemed like the head nuts were kinda tight when I adjusted them after work, but I did torque them all down a bit.. I wish I did have a torque wrench.. Where do I find the adjustment steps on the board?
 
"The metal shaft in the middle of the sprocket" is called the 'bucking bar'. It needs to be lubricated with a good grade of bearing grease. Behind the bucking bar is a ball bearing. It too should be well lubricated during installation.

Torque values: Cylinder head fasteners, 8mm = 120 to 140 inch pounds. All other 6mm fasteners should be about 60 inch pounds. That is the intake and exhaust manifold fastners.

Whatever you do don't start messing with clutch adjustment on the right side of the engine until you have an understanding of what you're doing.

Did you inspect the head gasket as I suggested above? If there is evidence that it leaked there will be a dark area on it that will indicate leakage across the gasket sealing surface.
You might want to remove the cylinder head and take a look at the cylinder walls. If there are deep scratches or gouging in the surface of the cylinder wall you have some serious problems. The piston needs to be at BDC, (bottom dead center), to see the full length of the cylinder wall.

Tom
 
I will give it a shot Tom, I would post pics of what's going on if I knew how to post pics on here. I'll get it taken apart and see what's going on
 
Just took off the cylinder head and inspected the surface of the cylinder-- nice and smooth, no gouges or scratches .. The metal gasket looked good, no sign of leaking from the cylinder head... I pushed the bike with the cylinder head off and the piston moved up and down with the clutch out and stopped moving with the clutch engaged.
The leak between muffler and the motor is spattering out fuel mix, that is the only sign of any wet areas.. It feels like the left stud on the motor for mounting the muffler is stripped a bit, so I don't want to torque it out... The right side is fine and no sign of wetness..
 
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Ps, I gave it a test spin afterwards and no change-- still does the same thing.. I'm thinking maybe its something with the clutch, so confused as to why it would be doing this...
 
Ok fellas, I got it going!!! I followed the steps of clutch adjustment on the board and tightened the flower nut.. Worked like a charm!! Thanks for all the help and suggestions!!!
 
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