Another ATC70 Not running right (Won't rev very high)

[tyman]

It's a 79 ATC70 Stock engine. Recent timing chain, valves, piston/rings and points/condenser.

The points are set perfect and in spec, the valves are correctly adjusted, the timing chain is on the correct tooth, the carb has been rebuilt and cleaned, the plug is brand new and it has excellent spark. It rev's to maybe 2/3 of what my 83 atc70 does and it just doesn't have any pulling power. It also gets an occasional stutter to it when holding the throttle wide-open. I replaced all the gaskets and spacers from the carb to the head and have ensured their are no leaks.

Any ideas?

[Thorpe]

Main jet dirty, or incorrect size? (I have had "moose" carb kits where the main jet was labeled correct size, but hole was greatly larger...)

[tri-Z ripper]

bad rings? check compression

[tri again]

x2 with everyone above.
Does it have a slow jet?
I know it's 'slow' but can hang them up off idle too.
Does it have a spark advance plate under the points?
They love to get stuck and not rotate / return easily.

[CRAZY70MAN]

I know you said points were spot on but it sure does sound like ignition problem?? I have yanked my hair out and drank a lot of beers fighting the 70 points at times. Maybe double check em? What type of air cleaner?? Stock??

[tyman]

stock air cleaner. The compression is good. Carb was cleaned, but i could try it again. And spark advance plate? Don't think it has one. points dim right at the F mark. brand new points/condenser so they're spot on.

[atv innovations]

How about a clogged muffler. Been down that road before.