Lost Compression???

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Jctmotorsports · #1 Post by **Jctmotorsports** » Mon May 10, 2004 5:00 am

Background...02 moto medium hours, died during a race, like the dead man kill came off, no fire back home. Had fuel, spark, compression at 28 psi. Pull apart,
Decompression Good
valves good
rings good
piston good
sleeve good
head gasket good
I useally like problems when I lose compression like this. Everything in this motor looks great, little to no wear, bearings all good(go figure) I would like any "make sure you check this" lines before I assemble. I've had a 450 kit on the shelf for the"next time it comes apart" but this is strange...
Chuck:confused:

Speed03 · #2 Post by **Speed03** » Mon May 10, 2004 8:33 am

Sounds like you may have a broken key on the flywheel.

thomez · #3 Post by **thomez** » Mon May 10, 2004 11:11 am

Decompression could have just stuck once on you?

Big Winky · #4 Post by **Big Winky** » Wed May 12, 2004 12:10 am

How was the valve cleanences?

I have also heard that sometimes a valve will hang a little and cause that.

jfarrar · #5 Post by **jfarrar** » Wed May 12, 2004 3:21 am

i recently have been thru this myself.not sure if somehow the decompression stuck(is it possible) or if a valve hung up.i been runnin vp and heard that it leaves alot of deposits on the valves.the stems looked ok but who knows.i got roughly 30 lbs compression then pulled the motor everything checked out ok hooked it up to the same battery did another check and got in the 70's.put it back in and it is fine.go figure.what type of fuel you runnin?i think im gonna switch to sunoce i never had any probs with that

Provy4life · #6 Post by **Provy4life** » Fri Jul 23, 2004 3:31 pm

sounds like u need the basic rebuild kit from atk. im in the process of getting mine back...should be at my dealer on the 26th.....YES!!!