Yamaha warrior 350 misfire

[Ja54563]

I have a 1992 Yamaha warrior 350 runs good for the first 30 minutes of riding but will start to misfire under load at about a quarter throttle to full throttle revs up good in neutral only does it in gear.

It as a new moose carb and new coil

 

[AlexMarioth]

sounds like maybe a limiter incorrectly deleted, or valves are too loose.