Gordy
Well-Known Member
The big end bearing is very difficult to replace, and if you ask me it's more worthwhile ordering a new iron bore and starting fresh.
Building bulletproof 49mm iron bore
- Thread starter CuriousJojo100
- Start date
CuriousJojo100
Member
Yeah I’m just gonna get a new one and start fresh. It was a huge b**ch on my part. The motor was the most powerful one I’ve built yet. It would pull a 28 tooth rear sprocket on a 26” rear wheel with ease. I would barely have to move the throttle at all and it would pull from starting speeds with complete ease. I do agree that while the pz20 looks cooler, I think it is in fact too much carburetor for that motor.
CuriousJojo100
Member
The reason I’m asking about bearings is because I’m gonna go back to a 24” real wheel with my 28 tooth. I may go with the 11 tooth front sprocket though. The goal is to reduce the strain on the clutch gears and build a screamer so I don’t lose any top end speed. I thought the bearings needed to be upgraded for a screamer motor though
Gordy
Well-Known Member
You can spin pretty high rpms on stock bearings. I doubt a 49mm iron bore would ever spin fast enough to wreck a bearing. As far as limiting drivetrain loss, just grease up the clutch assembly real good (but not too much on the actual gears, just a pea size dollop on the clutch gear. But grease the crap put of the spring assembly and bucking bar setup) with some lucas red 'n tacky.
Mike Cyanide
Well-Known Member
OK hear me out go 32t on 26s. 28 is much harder to pill than you think. MOST IMPORTANT- this was from a lean condition or air leak or both. You probably got a bad clutch factory. Sometimes no matter what they slip from poorly machined parts. I promise your drive train is of no fault. This is 100% failure from improper tuning
Mike Cyanide
Well-Known Member
Same bearings are in my motors that do bananas rpms. The wrist pin bearing tho can alway be better I've had really good luck with saw bearings. Find the equal size saw bearing and your golden. I assume it's 10mm
CuriousJojo100
Member
The bearing going out is 100 percent my fault. I should have killed the motor when my exhaust piece fell out. I was having clutch troubles before this though
Mike Cyanide
Well-Known Member
I know bud lol ya missed that point. 1 some clutches are junk right from factory from poorly machined parts. Adjust all you want they're junk. 2. Even b4 the pipe fell out you were super lean
Mike Cyanide
Well-Known Member
Your carb tuning was the problem. Coupled with a possible vac leak. The f2 only mad it much worse but this would have soon happened anyway. I'd go back to the factory carb or buy a bofeng and do the mod I do. I get 60mph out of a bofeng and 50 out of a stock nt. Who gives a s**t how it looks. I'm 10× more impressed when someone does it with a "stock" carb.
