i am working on a 50cc 2 stroke predator when i got it carb was gummed up. drained gas, cleaned carb, changed plug, and it runs but wont pull its own weight. i can raise the rear wheels and itll rev up as it should pulled exhaust to make sure it wasnt clogged same thing. Any thoughts? I messed with the mixture screw doesnt seem to help any

 

If you're sure on the carb,fuel supply then I'd check out the belt and clutches. Rollers could be worn along with the driven clutch carrier. Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse 0450203 Polaris | eBay

 

I pulled clutch assembly last night rollers seemed in good shape cleaned and put new grease on them as well as new fluid in gear case. I adjusted the idle screw up and it seemed to help a little bit as soon as i hit the throttle it falls on its face. I'm guessing weak spark under load but im not to good with 2 strokes.

 

Also this is on a 2001 predator if that helps any OPT

 

2001 they just had the Scrambler 50,but doesn't matter as the clutches are the same for all models. I'd suspect the rear clutch carrier if you haven't checked it out. It's just a centrifugal brake shoe type clutch. Item #5 on the parts breakdown I listed.