Help with ATC 70

[Mike O]

Just finished restoring my 85 ATC 70 and have what I think is a lean condition. Engine is totally rebuilt, CDI conversion, brand new factory Honda carb. Idle is fine, wide open it runs great, mid range 1/2-3/4 throttle it stumbles pretty bad. Other than a the CDI and a Spangler exhaust, it's bone stock. Main jet is a 58 and needle clip is in fourth groove. Tried dropping clip to last groove and set pilot two turns out and it stills runs bad at mid range. No air leaks anywhere, new gaskets and phenolic spacer. Plug looks grayish white. Thought about trying a 60 or 62 main jet? Any ideas or advice would be greatly appreciated. Really love this little trike but the poor engine performance is disappointing

[Mike O]

No ideas? Could this be a jetting problem?

[shortline10]

Are you using the factory air box ?
It will not run past 1/4 throttle without it .

See if it will rev up with the choke on ?