Compression problems Mornini Gyromat M01

Seems that my engine compression cant get over 100lbs but the rings and piston are all intact. I was told replacing the top end should fix this.. does taht sound right?* Moved to this forum by maize

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Re: Compression problems Mornini Gyromat M01

sounds wrong to me, several threads have been made about using the wrong tester, underreporting cranking compression.

looking at your post history, 3 years ago you needed the top end rebuilt

then had it running (lost exhaust) then lost spark.

not being judgemental, repair history tells alot about what it may need.

weak spark and low compression both leave the plug black and sooty

post here what compression tester you used, how well did it run after you replaced the rings last time?

Re: Compression problems Mornini Gyromat M01

Honestly I have someone working on it for me who said they tested it and said the compression is just around 100lbs. Also sent the pic Ive attached.

It ran pretty well after I got the correct rings. While riding one day it just stopped running and I could never get it to start after that.

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Re: Compression problems Mornini Gyromat M01

That mating surface is scratched to hell. Lap with 600 grit paper on a toolmaker's flat to rough in, then use 1000 to get it really flat.

Re: Compression problems Mornini Gyromat M01

run away from whoever did that to that head, butcher.

here is a link to an article about compression tester issues.

unfortunately, that head brings into question the other work they did.

one day it stopped running isn't specific enough to tell.

if someone can move this to repair forums, the quantity / quality of replies will improve.

this is trouble shooting 101.

Re: Compression problems Mornini Gyromat M01

Good lord, what did he use to polish that surface? A chainsaw?

Re: Compression problems Mornini Gyromat M01

matt boda1nz /

Moby Dick Wrote:

-------------------------------------------------------

> Good lord, what did he use to polish that surface?

> A chainsaw?

Haha!!

Re: Compression problems Mornini Gyromat M01

the mechanic working on it suggested I just find a new motor that fits my bike, will an m01 m02 or m1 fit?

Thanks

Re: Compression problems Mornini Gyromat M01

Downhill Harvey (OFMC) /
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