76 Harley gas cart lacks power

[Yofrankie]

I read others posts but none seem to be finalized with people checking back when problem is solved so I apologize if you’ve heard this one before.
New to me 76 Harley gas three wheel cart has little power.
Runs better in reverse but still slow
We put on a new carb
Checked the points gap
Replaced the starter
Replaced the condenser
Checked all grounds
Got the buggies unltd top end kit and installed
Cleaned out the muffler-wasn’t a problem
New battery
Checked for brake drag

I still have little to no power forward and little power in reverse

Can someone provide some ideas, esp if you’ve had the same issue and have successfully diagnosed and fixed

Much appreciated