mechanic123

Seems that way I've been kicking my guts out forever.

Looking for some help. 1971 Bultaco Matador SD 250 wouldn't start. I got 130 psi compression with new crank seals, piston rings and cylinder honed. Got fuel and spark as well. Been messing with timing trying to get it to start but it shows no signs of life. Any ideas are much appreciated.

Everything I see online is 250 2 strokes need around 150 to start though?

I'm getting a constant reading of 120psi. Would that be enough to get it to start?

Thanks for the idea. I checked the key and it is not sheared. Any idea why compression went down though? I thought 250 2 strokes were supposed to have atleast 150 to start?

I have a 1971 Bultaco Matador 250. Checked compression and got 90psi max. Replaced piston rings without rehoning cylinder and got 150 psi. Wouldn't start so I messed with timing and got it to start. It reved really high because I didn't have the carburetor tuned. I shut it off within 10 seconds of running. Went to start it again and it wouldn't start. Checked compression again and now it's at 120 psi and won't even attempt to start. Tore the head and cylinder off and no scoring in cylinder and rings are still intact. Any ideas why compression dropped? Any help is greatly appreciated. TIA.