Hey guys, my 1978 it400 has rebuilt carb, top end, & replaced spark plug. Plug wire is in good condition. Hard to start sometimes, other times 1st kick. Plug doesn't look excessively wet (though I'm new to 2 strokes). I tried adjusting the carb main jet needle 1 notch richer, without any change.

Suggestions?

Hi" hard to start ? when hot or cold ? how does it perform ie. tick over - W.O.T.- over-run , any surging ?

Hey guys, my 1978 it400 has rebuilt carb, top end, & replaced spark plug. Plug wire is in good condition. Hard to start sometimes, other times 1st kick. Plug doesn't look excessively wet (though I'm new to 2 strokes). I tried adjusting the carb main jet needle 1 notch richer, without any change.

Suggestions?

thanks for the reply blackhat250.

The bike is harder to start when cold, often starts better cold without the choke on, usually starts well warmed up.

The best way I can describe what the bike is doing is: decent power on take off, as rpm's get to about mid range the engine starts to sputter (surging yes) almost like a rev limiter.. if I stay in the throttle it will gradually go higher rpm's but limited change in power.

The bike is harder to start when cold, often starts better cold without the choke on, usually starts well warmed up. The best way I can describe what the engine is doing is: decent power on take off, as rpm's reach mid range it begins to sputter (surge yes) almost like a rev limiter.. if I stay in the throttle the rpm's gradually increase with little or no gain in power.

Sounds like air screw fully closed. backit out 1.5to-2 turns out. alas air filtre, clean it. and The IT400 is pre-mix, 32/1 make shure fuel is good, the reeds help mid-range if all of above is checked, inspect them ,,,,

Its a very old bike and I would be thinking...crank seals need replacing

My IT400 is in need of a tune. What is the better way to check the timing?