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

Installed almost 3 months ago. For the price it can't be beat. The hardest part was installing the small rings on the plunger and inserting the plunger into the glass, but other than that it was easy. The whole process from start to finish took about 4 hours. Make sure you have some good starting lube to cover the jug the piston slides into so you don't have trouble starting. I have no oil leaks and the power increase was felt the moment I started it. I was even a little scared it would fall apart! The weights that came with her were 9 grams and it was a bit heavy so I changed them to 6 and she runs ridiculously well uphill, in the wind, in everything. Couldn't be happier with my purchase. However, I have experience as a mechanic. So if you don't have these, expect some problems. Be careful and take one small step at a time. There are guides for such things, use them! All in all I was skeptical about the cheapness of this BBK as others of the same caliber are much more expensive but I'm glad I went for it. You should too. Happy riding! EDIT: (5/5/16) Hello again! I installed this kit about 6 months ago and it still works great! I'm leaking oil, but that's probably a blown gasket and my own carelessness, not the kit itself. I really wanted to add something I missed in my review; Where you screw in the spark plug, something sticks halfway, which I didn't even notice until yesterday. A typical requirement for spark plugs is "hand tighten bolt, then use tool 1/4 to 1/2 turn, depending on several factors." However, the hand was only half there on that head! Lately I've been having issues with spontaneous spark plug burnout and it's been confusing. Now I realize that I never actually screwed the cork completely flush with the head, which is of course very important! I'm surprised it worked at all let alone how it worked. HIGHLY RECOMMENDED, once you've received this, before you put anything on the bike, take a new spark plug (NGK CR7HSA, take it to the switch at pre/autozone/nappa/etc) and screw it into the cleanest new head . I was afraid he would undress like my old man, but that didn't happen. First it is hand-turned 3 or 4 times, but even that is only half. With the help of a spark plug wrench, I can screw in the spark plug flush with the head without much effort. I recommend doing this before installing so you can basically see what you're doing and avoid disassembly entirely. I had to buy a set again, mainly for the head, but figured it was only $60 and more spares wouldn't hurt. Don't make my mistake and think cork is good for initial hand tightening because it isn't. Mine got thrown out a couple of times and ended up blowing the head off. Their heads may be different, but the two I received arrived that way. Make sure the spark plug is fully screwed in before putting it on the bike! I'm open to any questions. Happy riding! Also, I really like this set.