GY6 Cylinder Rebuild Kits Kymlaa 100cc Big Bore Kit for 69mm Valve 49CC 50CC 139QMB Moped Scooter Engine 50mm Bore Upgrade Set with 6pin Racing CDI Ignition Coil Performance Spark Plug Clutch Spring

If there is a single bad review on this item it was either a fluke or lack of installer experience. This kit came exactly as shown. Was very easy to install, and took 2 hours total and wasn't even rushing. Watch a few YouTube videos and DO NOT RUSH! Everything went together perfect, and smooth. All parts including exhaust studs were absolutely fine and same as stock. Bike started up within a few cranks once gas got back in to the carb. The power is night and day. Have no problem getting my tao 50 pony up to 40-45mph now, and quickly. Pulls wheelies fairly easily now as well. Literally was getting smoked by my buddies mopeds earlier in the day, and went back to his house after install and put bus lengths on his 2 stroke moped. Much more responsive. Keep in mind I already had an upgraded jet (85) and intake and exhaust and a 7/5gram split slider swap. But literally runs perfect as is with only a small idle adjustment. Highly suggest this kit. I haven't even installed the cdi, clutch springs, or big main engine gaskets either. Only complaint I have is the spark plugs that keep coming with these kits and the cdi kits are trash. Use ur stock plug or a new stock one. Other then that we'll worth the money and definitely a good buy.

kit really worked well. ridden over 300 miles in one weekend at full speed!

This big bore 80 kit was intended for my 49 cc speedy amigo. Everything arrived in it's proper packaging. Nothing was missing. Everything fit like it should. It just took a while and it's a very technical job if your not handy. Thanks to YHWH my neighbor is a motorcycle racer/mechanic and without him I could not have done it myself. We replaced everything except the oil rings because it was to hard to get to. If you buy this I highly recommend you change out everything and also get either a bigger carburetor or have it rejetted. Also throw in an after market exhaust and you got yourself a fast lil scooter. Def to fast for me.

I definitely got a bad product! rocket arm plate was not drilled properly. Ended up swapping the arms to the old plate. Spark plug threads were very poorly done and upon removal of the spark plug due to a no start condition after assembly, the threads came with the plug. I dragged my feet getting this thing together so Im screwed on this whole ordeal. This project has been one thing after another and its simply not worth it for the 40mph I was gonna get from it anyways.

10/10 worth the upgrade from 50cc. The slight power increase is all I was looking for. Easily get to 20 mph and topped around 35-38. All parts were correct, NOTE NON EGR CYLINDER HEAD, but CDI didn't work. Left the old CDI installed, works fine.

Bought a 49CC scooter for my Daughter for Collage, But it took 2 blocks to reach 30mph, any hill it would go from 30mph to 10mph (top speed downhill 35mph) not cool. I deemed it to be too dangerous do to the speeds on the roads near the collage was 35 to 45mph in a hilly area. OK so I installed this kit and a aftermarket Exhaust. Now she out accelerates my wife's car from 0 to 20mph top speed 45mph on the flat, going up a 6% grade hill she holds 35mphSo this year we took her to the 2024 Sturgis Motorcycle Rally in Sturgis, South Dakota and she rode her Scooter down Main Street with the Big Bad Harley's and Indian's. My Daughter had a blast over 200 miles on this kit. PS took about 3 hours to install this includes watching the videos on how to do it.Good luck and happy Scootering/Biking

Installed and was only able to get 75 psi compression. Gasket arrived bent. Should of sent it back instead of spending 2 hours installing it just to return it. They accepted my return but my time was wasted . See attached photos this is how it arrived! BENT ! Other components were good .

Make damn sure you know what you’re doing otherwise have a pro install it for you. Seriously easy to install if you’re mechanically inclined and take your time and don’t rush. I was able to increase horsepower and torque. 50mph average speed, and same gas mileage.