Glixal High Performance Secondary Transmission Gear, GY6 49cc 50cc 80cc 100cc Racing Final Drive Gear Set for 139QMB 139QMA 147QMD Engine Scooter Moped ATV Go Kart (17T/49T)

I didn't gain much top end speed. Which was a surprise. But that is what a lot of guys say after doing the gear swap. Acceleration actually seems a little bit quicker though. I had a wheel bearing starting to go which may have had an effect. Fixing that todayThe way the CVT works plays a major role in the acceleration curve. I've tried running 7g sliders and 6.5g rollers and 1500rpm contra and clutch spring kit. Trying to get to a top speed in the high 40's maybe even top 50mph.

Don't do this unless you have a really quick 50cc qmb139 or a big bore kit. replaced and pressed the gears in one day at my local shop for 40 bucks. Make sure they fit right. Fits with my 1p139qmb got me 5mph on average more. I probably could've used a more aggressive gear ratio but this works and it's the more tried and true ratios for my set up. You WILL lose take off speed it's a given. But I get 40 mph average on my moped and I feel it's perfect now. Max downhill is usually 45mph max. 20mm carb, 80cc bbk, A9 cam, open exhaust, 1500 rpm clutch and torque spring.

I got a too high of a gear and it didn't work as well as the old gears that I had to change back and not other problems once I changed them so it was my fault not the products

I disassembled my gear box, pressed the old pinion gear out, and I was very disappointed to find that this replacement pinion gear would not fit! There is a 2mm difference, see photo, and it WILL REQUIRE you to take the part to a machine shop or if you own a lathe, you can turn down the new part 2mm for a perfect fit. Measure your parts before ordering this set, I’m not sure why the specs are not listed to avoid this hassle!

Bought these gears for my secondary vehicle a white pony 50 big bored to 100cc, and I’m yet again impressed with how easily everything went together your gonna need a hydraulic press or the old fashioned way with a socket and hammer, you can hit the old gear out and damage it (your not gonna be using it) and carefully hit the new one in using a socket so you don’t mushroom the parts where it slides into the bearings, other than that it’s a smooth ride very fast it doubled the top speed, it’s on par with my main vehicle now. Again very high quality parts and 100% recommend buying for anyone scooter who’s lacking the speed.

These gears are nice but there was no performance gain. My stock gears were 51/15 so I expected some kind of gain with these 49/17 gears. My gear ratio went from 11.05 down to 9.36. I just don't understand what's going on!!!

You have to take the stock drive out of the old gear and install the new drive in. The top end sits on top and fits perfectly I gained 5mph at the top end I am now burying needles.

Awesome transaction!!