250sx problems

[Rockthunder]

I have a 85 250sx. I recently rebuilt the top end on it but I have some problems. It will start and run but you have to hold the throttle wide open, and it just barely will run, let off the throttle and it dies. Does this sound like a timing issue? Thanks for the help!!

[Dirtcrasher]

There is no ignition timing on that model. With the flywheel cover cap off and pointing at "T" the cam should be set with both lobes down and no pressure on the valves, I think there's a mark on the sprocket.

Other than that if it ran before it's definately something you worked on - go over it again and maybe you'll find it.

[Rockthunder]

I have never had the motor running myself. I put it together from 2 different motors. I adjusted the timing just like you said, but was wondering if i was 1 tooth off or something. Maybe it is carb problems?? I will try a new carb tonight.