Home Forums Gear Horses and ATV's Yamaha Big Bear 400 Down On Power

I inherited a 2001 Yamaha Big Bear 400 (carbureted) that was used on the family farm. Like most farm machines it has been worked pretty hard over its life. It is down on power but only at higher speeds. It starts fine, revs fine in neutral, and takes off at lower rpm like normal. It kind of tops out at higher rpm. It doesn’t stutter or fall on its face, it just doesn’t respond to the throttle. I’m not a mechanic and the machine is old enough I don’t want to dump a ton of money in it.

I have:
Replaced the air filter
Seafoamed the fuel and intake
Rebuilt the petcock (leaked)
Checked the plug
Verified good fuel and fuel flow

None of this has fixed the problem.

I have considered:
Rebuilding carb
Worn cam
Worn rings/compression loss

Any ideas?