[Willie34]

Put new piston and rings in, new cylinder, new carb new reeds and it’s real hard to start wen it does start and gets warm it runs good juts real sluggish on low rpm’s once the rpm’s gets high it’s like it has power can anyone help me. Thanks

 

[jaguar]

If it's not due to incorrect jetting on the new carb then it probably needs new crank seals. They don't last forever and when they stop sealing you lose crank pressure which can have many different symptoms. Sometimes with a skinny screwdriver you can pry them out but if you can't then you need to split the cases to replace them. Here's how to tell if they are leaking: When the "wet" (usually right) side leaks you get a lot of smoke because tranny oil comes into the crankcase. When the dry side leaks then air will escape out of the crankcase past the seal and you can detect that with soapy water sprayed onto it. (Make it soapy with liquid dish soap) If it leaks then you will see bubbles come out of it. Losing pressure there reduces the delivery ratio and makes it run lean, but not equally at all RPM.
For a precise jetting guideline go to dragonfly75.com/moto/carbtuning.html