1980 Honda atc185 no compression

[Madmax1726]

Recently picked up nice 80 atc185 , motor turns over has strong spark , but seems to have no compression, have not tested it with a gauge ibhelp my thum over the spark plug port and pull the recoil and has no pressure, also the decompression lever won't stay in the up position , not sure what position this lever should be in , if you lift the lever up it just immediately snaps back down any info would be great thanks

[DohcBikes]

The decomp is likely working normally, unless you have a stuck valve.

What it does is open the exhaust valve. Sometimes if the valve is already open in that particular engine rotation position, Then the lever will not stay up.

Do you have a service manual? Adjust the valves per the manual.