Re: Moby just won't run

The plug can be wet with gasket leaks .

The motor still pumps , just not a proper air/fuel ratio .

Do as Den 23 suggests and then put it back together . Torque the head nuts .

See what happens and go from there .

Re: Moby just won't run

toss that compression tester, no way a leaky blowby piston and a leaky head would give u 120 compression. ^^ those rings gotta move freely to seal on the cylinder walls. hows the cylinder walls?

Re: Moby just won't run

mike thompson /

rings and cylinder wall look great. The small leaking I could witness was where the head gasket should be. When I squeeze the decomp, compression tester reads 0. It reads 120 because the leak under the head must be small.

Re: Moby just won't run

> mike thompson Wrote:

> -------------------------------------------------------

>... When I squeeze the decomp,

> compression tester reads 0. It reads 120 because the leak under the head

> must be small.

When you're doing a compression test are you twisting the throttle completely wide open as is required?

Re: Moby just won't run

mike thompson /

To Den 23: I did not hold the throttle wide open when doing the compression test and I don't see how that would effect the compression at all. Has anyone else ever heard that the throttle needs to be held open to do a compression test??

To Pat Splat: I just re-read your latest response...do you think the scorched appearance on the piston is blowby on the rings? Meaning not normal (like others have said)? The cylinder walls and rings really do look really good.

Re: Moby just won't run

> mike thompson Wrote:

> -------------------------------------------------------

> To Den 23: I did not hold the throttle wide open when doing the

> compression test and I don't see how that would effect the compression

> at all. Has anyone else ever heard that the throttle needs to be held

> open to do a compression test??

Wide open throttle is the standard for taking a compression test . Logically , it allows the maximum amount of air into the compression chamber .

Re: Moby just won't run

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Re: Moby just won't run

mike thompson /

UPDATE! I got it running beautifully. (very) long story short: I really needed the head gasket it was missing. When that was replaced, I could get it running pretty shittily with the timing advanced to 2 and a hot plug with a small gap but it ran for fairly short periods and then fouled plugs. Once it was running some, I found a big air leak in the carb behind the shim where the rubber gasket was also missing. I replaced that and it ran a little better. Remember it had a old CDI already on it and the spark looked real good but when the bike would quit, the plug would be soaked. I put a new CDI on (that $75 La party one) and the plug would throw a fat arc like 1/2" away from the cylinder head! Literally. So, once the new CDI was on, it started first kick, ran very smooth and hit 35 mph on the flats. I am physiced. Thank you all for your inputs.

Re: Moby just won't run

Richard Eberline /

Since your bike dosen't run and you have all the answers.

Rebuild your motor, new seals and gaskets.

Fresh gas and time motor per specs.

You could cross hatch cylinder and add new rings.

Carb down jet.

Re: Moby just won't run

mike thompson /

Uh, DOES run.

Re: Moby just won't run

You got it going great, just dont mess with the cylinder bore. Its chrome nickel coated and will last forever if the piston is kept clean and it doesnt overheat.

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