Check the compression of course. But also check the exhaust port for excessive carbon deposits. Sometimes you have to clean them out and sometimes you have to de carbon the top of the cylinder. Also, If your exhaust pipe is all gummed up it will restrict performance. Make sure your airfiler is clean. Looks like a great start to a fun project. I love the fat tire 2 strokes.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90