Review on 🛵 Enhance Performance with GOOFIT Big Bore Cylinder Rebuild Kit for GY6 50cc 139QMB Racing Scooter Parts - 64mm Valve Upgrade by Rudolph Mceachern

I have just over 100 miles on this set. My 50cc Tao Tao did 27 mph (40 mph on the odometer). With this kit and an improved and retuned carburettor it now tops out at 40mph (55mph on the odometer). Acceleration takes place day and night. I can take off quickly and move on. The hills are no longer a problem and there are many hills around me. Installing the kit was pretty easy. It took about 7 hours but I was very careful. My stock engine had 69mm valves and the kit requires 64mm valves. Since the kit included rocker arms, I assumed that was the case. I moved my hands to my old base and installed the kit. If you use a bearing head, it will fail quickly. IMO, that's the number one reason for failure. The rest of the set fits very well. The metal in the motor is soft, so be careful not to snap anything. I already have a few "problem" threads but they are still hanging. The piston was a little tight, but a little engine oil worked it out. Yes, attaching and detaching the wrist pin clips is the hardest part. BBK doesn't have EGR, so you're basically ignoring this whole system. You can remove it, but I left everything and plugged it in. My carb runs an 85 Main and 33 Pilot and I have a pod filter, not an airbox. BBK got me about 3-5 nozzle sizes. I prefer to use it a little richer to extend its lifespan. I haven't tried the included 8g rolls yet. I plan to optimize the variator in the following way. I found the scooter harder to start in cold weather after installing it, but it starts. This means the standard 4Ah battery may need an upgrade. On warm days it starts immediately. Updates when something changes or explodes.