Poor top end performance

[asleepz]

Alright, stock motor, UNI filter with no lid and HMF slip on with a 138(I think)/40 jetting.

It just seems when I get around the last 2k RPM of the operating range it's really not pulling that hard anymore and it seems I'm rich down low. I've got black soot in my exhaust that builds up pretty quickly.

I ride at sea level or below.

Any ideas?


Btw, I didn't adjust the clip on the needle but it pulls nicely down low and in the mid range.

[asleepz]

Also!

I'll be getting new tires soon, I'm not sure if I want 20s or 18s but I just want something with a flat tread pattern instead of these balloons I have now.

I've already got a 14t front sprocket if I go with 18s should I move my rear sprocket down to a 36t and will the stock chain work with it?

[asleepz]

Sorry for all the addons but I'm looking at rocky mountain atv and looking at these wheels

4/110 Motosport Alloys Sportlite Wheel 10X8 3.0 + 5.0 Machined

Does that mean I'll get a TOTAL of +5" of width in the rear?

[badtothebone250]

The wheel will be 10 inches tall by 8 inches wide. The 5+3 is the offset of the wheel.

[badtothebone250]

And unless your riding striclty motocross, you will want a 20 inch tire.

[asleepz]

alright I'll keep that in mind, thanks