flyjay77

I am rebuilding a old saito 150 that I cracked the case on a few years ago , have done this many times with two stroke, I took apart the engine, everything is good till I put it back together , the engine seem a lot tight so I took the back plate off and saw a F on the Rod, thinking that this means front I took the cyl off and fliped the piston around, now I have no compreshon on the engine at all , its like the plugs out, the exaust has lots of presure and when plug, it shoots a lot of air out of the back plate tap fitting. befor I turned the piston around I had Loads of suck through the carb and loads of blow through the egaust . have not run it , I just turn it over with a prop . all I need now is help/ /

jason,

aerowoof

sounds like the valve are not closing

BB Modss

rebuilding a satio twin takes a lot of time,you might have galled the pistons up pretty bad if you mixed the conrod's up,pull it all apart and inspect every part again,make sure you toss a fresh set of piston and ring's in there,its a must for a decent rebuild. BTW it kinda sounds like you got the cam timing off..