Chanoc80cc Big Bore 47mm Cylinder Rebuild Kit for GY6 49cc 50cc ATV Scooter Moped with 139QMA 139QMB Engine

This kit fit my little Chinese scooter very well, slid together with just the right amount of resistance, and looks completely stock from the outside.There are no instructions with the kit, only parts, but it does include intake and exhaust studs and exhaust nuts (not needed for install, but good to have for spares!). I got 3/4 through reassembly and discovered that the kit doesn’t include a cam chain tensioner gasket, so be sure to order one (about $1) or go to the local scooter shop like I did ($5!).I don’t know how it runs yet, I’m on my way home with the gasket, but I’ll update once I’m riding again!

Out of other BBK kit's i have installed this one on 2 mopeds it is the best in quality casting,fitment and gaskets.The stud bolts for intake and exhaust that comes with this kit if using your original head remove the old studs and replace with the studs that come with this kit i use a drop of mid grade blue lock tight on all my scooter bolts retightening all bolts and nuts during break in exhaust bolts especially.Install a new NGK spark plug while you have head off making sure it is tight.Best valve gap is .004 intake and exhaust.A ring compressor is not needed if rings are installed correctly the rings will compress going into jug using your fingers to compress the first 2 rings"I use axle or marine grease on the new jug and piston lightly to prevent first starts being metal to metal.To have the best results install new exhaust,intake gaskets and a new intake manifold.Installing a #90 main jet with throttle needle clip set 2nd down from top.

The piston and rings were fine. Wrist pin was missing from the kit as well as some other bolts and nuts, so I just used the old ones. The cylinder had some insignificant damage due to the improper shipping packaging. I would ask for a replacement, but they ran out of stock.

Amazzzzing quality kit. Stock carb, intake, exhaust, variator, clutch, gearing and what not. High flow air filter, 7g Dr. Pulley sliders and You will hit 55mph. All day long and out accelerate a bone stock 150cc 4T Chinese scootie scoot all day. Not gonna knock a star, because every other company does this. But... Please include a cam chain tensioner gasket. They almost always break when you pop that off the jug. Yes I know a little RTV will fix that or you could just cut one yourself. But seriously... Just include the damn thing, please and thank you! Will buy many more over the years. One of the best deals out there for something this high quality.P.S. If your not hitting 50+ you're doing it wrong or the CDI is restricted. If there is a wire coming off the CDI that connects to the CVT your restricted. You should be able to unplug it at the box.P.P.S. I would give 1 Gagillion stars if I could.

I added this Big Bore Kit to my Solana YB50QT-3 scooter. I have never done this install before, but it took a couple of hours while watching some youtube videos and I had no problems. Running strong after a couple tanks of gas. I also added a new carb [B07SN1JZZ9], 7.5 gram rollers and 85 main jet [B06XHZKC8M] along with a generic pod filter and welded a custom exhaust with a bit more airflow. I'll do 40mph [GPS Verified] uphill with 45MPH on flat grounds and had a top speed of 54MPH downhill. Definitely recommend for anyone who wants power from your scooter. Stock 50cc just doesn't cut it.

My order did not come with a Wrist pin or one of the intake manifold studs, would like Chanoc to send these parts out right away. Chanoc, please get back with me ASAP

So here it goes just buy it n install it made such a huge difference main one up hill it drops to 19 mph now it never drops speed I’m climbing hills easy n fast down side it eats more gas now but in all well worth it I did it myself n saved so much on labor the price is great so is the product I’m truly happy

I love this bore kit it has a deep sound and alot of power i reached 63 mph with this kit its straight forward and basic bolt on and alot of torque