Moto 4 cutting out

[fivepointfivesi]

I have an 85 moto 4 200 that seems like it misfires and looses power when under a load. Example first gear all ok, second gear all ok, third gear at 3/4 throttle going through snow or up hill it starts loosing power and missing. It did this before i rebuilt the top end, replaced and rebuilt the carb, and put a new plug in.

I also noticed that when cold, it idles fine. but as it warms up i constantly need to speed up the idle or it will die from idling too low.

Im thinking possible weak coil, but i would like to know what all you think before i go throwing parts at it.


Thanks
Mike M

[seddon]

that is what i would say or a short some were

[fivepointfivesi]

Well i put another coil on it and no improvment was made. I took the plug out and it was black. So i took the carb apart and noticed it had a 117 main jet, i put a 115 in it and lowered the needle to the second groove. It runs about 80% better.

Im wondering if it would hurt to go to a 112 jet? I just dont wanna go too lean. I know that they were supposed to have a 115 from factory. I have a uni air filter and a 10.5:1 piston in it. i wonder why i would need to go lower yet. Any suggestions?