Scooter Big Bore 150cc to 170cc Cylinder Head Gy6 157qmj Performance Exhaust #99004

the cylinder i got seems to be made to use a small stroker crank.at tdc the pistion is about 1.5mm from the deck height. but i got 65 mph with the low compression and 87 pump gas. the header broke at the support bracket after 3 weeks of riding. scoot is used as a go to work transportation about 30 miles round trip 6 times a week on honolulu roads... yes the roads here is that bad.

Worth it but the exhaust is too long and heavy, you'll have to have brackets fabricated and welded at muffler shop.

Everything came in one box and packaged nicely. Don't see any way it could possibly get damaged in transit. It was well thought out. Everything was as posted. I say everything was really good quality and that it was way better than stock items and added a lot of power. The machining of the block wasn't to bad. The only complaint I have is.the mufflers a hair long but not bad. It sounds great too. Believe me. I don't normally leave feed back but I had to on this one.

Had to do some custom fitting to get muffler to work. Its not a 170cc big bore kit like described. This is a factory gy6 head and piston. Nothing special. Dont recommend.

Just have a question would u have to bore the whole sleeve of my motor