1978 atc 90 - runs mint, no power? Pic enclosed

[hdeuce]

Just like the title says. My little 90 runs like a top, idles fine, revs up fine but when I ride it (up a small hill) it seams to be lacking any power. My 1984 110 will smoke right by it. I am sure it is a jet issue but I don't know where to start.

[3wheelrider]

It might be your clutch discs/plates slipping and weak springs? That may be why it feels that way...possibly? just a thought.

[Shorty]

Thats a pretty nice 90 I'd say.

[hdeuce]

thanks guys but I am pretty sure it is an issue with the carb.

[tri again]

where does your spark advance come from?

does the 90 have a spring loaded plate behind the points that's supposed to move?

[Texas 200x]

I agree check your point gap. Play with it a little. If your plug isn't completely fouling out, or white I would look at point gap. Adjusting .012 to .014 makes a HUGE difference on my 70's. Playing with your gap (sounds kinda funny) doesn't cost anything, just remember where you started so you can always put it back if needed.

[atc350xer]

How's compression? I have the same lack of power with one of my 90's, but I think it needs the top end rebuilt.