Hoping there might be someone who is knowledgeable and familiar with this issue... The infernal machine was purchased used and is a four year old build. It ran great up to this year when it began to get fussy starting, loosing power and then starting ok but not wanting to run. I went through it and as everything fuel/air seemed good, I decided to change out the Mag and CDI. It has the same problems and I'm thinking the problem may be engine related. As mentioned it will start, but the cylinder gets instantly hot. It will stall out after a few seconds. On a test ride it runs poorly then buck and quits and the rear wheel locks up with the clutch out. It also has started to smoke which I put down to oil mix, but I'm thinking this may indicate rings? I pulled the top of the cylinder and the piston and walls look clean and smooth. I've also checked for movement by turning the mag magnet bolt and it turns then seems to become more difficult then smooth again? This procedure can not be done by rolling or turning the wheel by hand. As it is a 49cc, I'm wondering if it might just be simpler to replace the motor vs dicking around with repairing or rebuilding an motor that is getting hard to find anymore. This bike is incredibly fun to ride when it does run, but a heartbreaking little money pit.