Tuning Help

[EJ Racing 07]

Hey there, I need some help we have an 07 Pro 90 and I am in the gray area when it comes to tuning a 2 stroke. I'm running 4.5 wights, stock gearing and for the rest of this year stock motor. It takes off good but at higher RPM's it just sounds like it is missing. I live in MN and its on an average 65 to70 degrees and the elevation is about 1200 feet. I think I'm running 42 and 120 in the carb now. Is there any advice out there or any other thing i can do? I just think that even being stock it should run better then it is. Would better reeds make a difference?

[mmullins14]

I would put a Koso or ZTR 2000 rear spring and 5.5 rollers in it and I think it would run fine.

[wrhracing]

Tell me what spark plug and what color the electrode is you could be to rich on the main. Or just need a new plug.

[EJ Racing 07]

BR9ES is what I'm running and the color is a light brown. I dropped the needle one clip and that seem to help a little for him just running around the yard, haven't had it on the track yet

[riding4fun]

Have you checked to see if your belt has full travel. From what I have heard the 2000 ZTR spring is really stiff and may be hindering the belt travel.

Take off would be great but top end would suffer.

Darrell

[marsrace2]

from what I know that is the wrong plug, try bp8es plug and I would also check and see how far out the air screw is.