Very low compression in cw direction

[doug9694]

When doing a compression test on a 86 Spree I turned the flywheel clockwise and there was way low compression. Turn it the right direction and compression returns but is only 80 PSI.
It is hard to start and runs fair for 5 minuets then bogs to 5mph. Let it cool and it does the same again. Starts with one kick when warmed up but real low speed under load. Runs fast when on the stand.
Is there some sort of directional valve to keep it from running backwards or perhaps a seal that leaks when shaft is reversed. ?? Bearing and end play is no slop. Will not hold a vacuum or pressure

[doug9694]

I took the head, jug and cylinder off after getting a 80 PSI compression. Booth rings had a piece missing where the locating pins are. Resulting in a 1/4" ring gap each.
My piston is a .5mm and has worn down to a .007 clearance between the cyl. ridge and skirt, .013 just below the ridge. Service limit is .004. This is why, I think, that when
I turn the flywheel backward slightly that there is compression lose. My theory is that the engine, 8,500mi.??. formed a groove. Going backwards forced the piston, rings cyl.
out of that groove and opened up the clearances releasing the compression.

How do some get 150 PSI. Is this from a new rebuild? Perhaps they meant 105? Looked at the gasket and don't see how that thin of a gasket, if left out, could give that much increase.
Do they have non standard parts?. Made a typo error or what??
The compression ratio of stock engines is 7.2:1 = 105.8 PSI. Another said that a Spree needs 120 to run right. So, How are all those stock Sprees running with just 105.8 PSI??
I am thinking, perhaps there is so much carbon build up in the combustion chamber of those who got those high readings they think that is normal?? What am I missing??

My jug is the GK8. There is evidence of over heating. Black carbon inside the piston and some on the wrist pin.
To wear the cyl. to .006 it must have been run WOT all its life. A 2 cycle Suzuki from the same era got 50,000 to 100,000 mi. before rebuild.

[patthesoundguy]

Just buy a new top end and you will get around 120 to 125 psi compression. 150psi compression is high for stock spree top end. Sprees have been reported to run kind of ok at just above 90 psi but its not the norm and the book says it shouldn't and normally they wont. Anyhing in the 100ish to 130 should be ok. check the reeds out as well make sure they are ok, they usually are but anything is possible. There are many factors that lead to having these top ends wearing out. The excess carbon leads me to believe that somone did not trust the oil injection and ran pre mix and over did it. That in itself could cause over heating by displacing fuel in the air fuel mixture. Also a lack of air filter over a long period of time would allow lots of contamination to enter the cylinder and combined with the lean condition lack of it caused that could explain the bad condtion of the cylinder. And these cylinders aren't exactly meant to last 50,000 miles. Sprees were meant to be cheap and easy to get while having some reliability. If your spree has 8500 miles that's a crap ton of miles for a spree top end and would explain the need for a rebuild.