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

Very good product. Trade Council here. The kit comes with an oil pump, just like the original. If your oil pump is working, simply set the oil pump aside and only install it when needed. Installed an A9 camera with this kit. recommend camera. The head is a small valve made of connector and valve cover (the valves are embedded in the hole and the hole covering the breathable dremel comes out of the cover and the dremel comes out of the hole. But avoid expanding the channels, there are very little wall material in some places, just try to remove a large wart formed to hold the valve bushing pressed in. On a base 50cc engine you get just over 80cc with a 50mm bore (formula : Radius X Radius X Stroke X Pi (3.14)) or similar with this kit, 25 x 25 x 41.4 x 3.14 = 81.44 or 81.5cc It says 100.cc kit but each and his brother sell it like that carburetor, do NOT buy 24mm carburetors, it's overpowered and you'll be in trouble dropping the carburetor and getting a carburetor you can adjust and open up to change injectors. With this kit you can go anywhere with a main jet around 80 -83 start. Watch Youtube, many installation videos ovke and setting. My scooter is currently cruising at just over 60 mph and has very good throttle response. I recommend installing a 2000 RPM Torque Spring (Red) in this kit. Drive with the highest possible octane number, because with this kit you increase the compression significantly. A word of warning, many people buy a racing CDI and have trouble getting started and don't know why. Many of the racing CDIs don't slow down time at very low RPMs (like starting). If you want to install a racing CDI on your scooter, look for one with a lead and slow curve, otherwise you'll blame this kit or settle into a long carburetor repair that fixes nothing. Stick with the standard CDI (standard CDI slows down on start) until you find a lead/lag CDI. This kit comes with an extra gasket you will need. And the parts are well made. I would take the time to polish the piston top and combustion chamber to a mirror finish, being careful not to damage the valve seat. The valve seat already has a 3-corner cut when delivered, so nothing is needed with the valve seat. You can, and I recommend, grinding down the valve and making a mark where the wakwe will sit and trimming the valve back to and close to that mark. You can also do the valve head perimeter, edge. Make it round and you'll get better valve flow. If you have a steady hand you can wrap a piece of protective leather around the valve stem, place the valve in a hand drill and file the valves. With small additions you will outperform all major valve heads. I am very satisfied with this set and can only recommend it. You can just bolt it on and get a much faster scooter or make all the little changes and get a rocket. Warning. They have a larger motor and therefore more heat. Be very anal when putting on the cooling jacket, it pays to line small cracks and holes with black silicone. Good luck to all.