First remove the spark plugs & look at the top of the pistons where the valves if stuck open would have hit the top of the pistons.
Second, put 100# of air pressure in each cylinder with the valves closed in each cylinder you pressurize.
That will test real fast where the loss of compression is from.
It will come out the exhaust if you have an exhaust valve leaking, or bent & not seating, open the carb butterfly up & listen for leakage out the intake valves. Then pull the crankcase breather cap off & listen for leakage from the rings.
When you pull the spark plugs to inspect the crowns of the pistons for physical contact if you find contact areas, pull the head right then & there & replace the stuck & or bent valves.
If you feel the rings are stuck in the piston ring grooves, put pb blaster or seafoam penetrant in each cylinder regardless of what you find on the top end.
The air pressure test will reveal your problem, good luck Bill
Second, put 100# of air pressure in each cylinder with the valves closed in each cylinder you pressurize.
That will test real fast where the loss of compression is from.
It will come out the exhaust if you have an exhaust valve leaking, or bent & not seating, open the carb butterfly up & listen for leakage out the intake valves. Then pull the crankcase breather cap off & listen for leakage from the rings.
When you pull the spark plugs to inspect the crowns of the pistons for physical contact if you find contact areas, pull the head right then & there & replace the stuck & or bent valves.
If you feel the rings are stuck in the piston ring grooves, put pb blaster or seafoam penetrant in each cylinder regardless of what you find on the top end.
The air pressure test will reveal your problem, good luck Bill