Maddog 50cc Final Drive Gear Up Kit for 90cc 139QMB. Buyer Beware 

@@hoedemakerbart I could not find any lower gears than the 15/52. I would like to actually gear it down

@@GhettoWrench AliExpress

@@GhettoWrench many times primary has a bad fit or wont fit at all, lately i had this with a doppler kit.. very bad engineering

So what’s the best gearing for these Chinese scooters

@@Smodlee if you upgrade the gy6 50cc to 80/90cc kit with the head and race cam,only then i would go lower gearing, 50cc is not strong enough . Stock secundairy i dont know out of my head, but should be around 15/51 so if you go like 17/48 you will have more top speed

Ya that is a 212cc right? Quite a bit more power than the 50.

@thelagmeister I have NOT balanced them. This bike I bought in 2024 new in the box says 2022 on title so for 2 years the tire has sat on a piece of angle iron and has a dent in it giving it a vibration.

@@Smodlee mine is 90cc and big valve head and NCY Cam etc also... I wouldn't think so. I'm pulling it out.

That is the GPS "sticker" on the GoPro 9 black. I just bought a new gopro 12 black and go pro has removed this feature. They must be talking to iPhone. WTF. So pissed as that is the main feature I like. The 9 is old and been ran over a few times so figured I would upgrade. It was a downgrade. LOL

@@GhettoWrench thank you. I own a knock off Chinese brand of Go Pro and it doesn't have the feature either. I will try to find a phone app to do this.

@frednetherlands887 I guess there is some phone app guys use to overlay maps and speeds on their videos for new gopro that everyone uses so gopro dropped the feature. I have to get smart on that.

@@GhettoWrench thank you. I will check as well.

@user-gz4gi8qu6o do you know what RPM you are at when 37mph? Also is the variator 95mm Polini "speed" variator? It takes a lot of power from like a bug bore kit and cam etc to turn a larger variator than the 87mm stock one.

@@GhettoWrench no i dont Know the rpm. So I should try the Orginal variater again?

I can't find lower gears for this than 14/62 that was in there. Only thing I been able to do to gear it down is that smaller tire and it went faster. Guess I can put smaller variator in but seems like I'm going in circles.

@Smodlee I went back to stock gears. 15/52. But I'm also running a 95mm variator which is a pretty good gear up step

I’m running a 100 main and 38 pilot on a 90cc BBK with a pwk21 carb and uni filter and I’m getting 49 mph with 6g weights and stock clutch.

@@Smodlee for sure. Then the guys out west at sea level run like 130s since they have zero humidity. 49 is moving. Does it have the fat tire .... maddog?

@@GhettoWrench no flat tire it’s a 2022 vitacci Denali 50

@Smodlee oh ya. For sure faster than a maddog.

@@GhettoWrench hey don’t have the link where u got the gear up set??

I guess but I am just going in circles. They are already at 4 grams. If I go grams they have good RPM but push the belt up the variator. Still no faster. I am gonna try a smaller variator next.. but just going in circles again. Gearing down the CVT to make up for gearing up the rear

​@@GhettoWrenchI keep coming back to this video a lot. I finally got that 72cc BBK on and it's gonna be time to tune my CVT and gearing soon.

@hesperidesbell4643 when I bump up the RPM with lighter rollers it just has high RPM and goes even slower. I'm like a dog chasing my tail. I was at 4g and the 3g won't push the variator all the way so it never gets in high gear

​@@GhettoWrench how does the wear line on the pulley look when you check after those rollers? EDIT: a lot of the groups I'm in on Facebook swear by polini CVT parts and I've seen a few claims that you can get a stock 139QMB to 50-55 with those parts. Idk how true it is but what I was wanting to do now is compare the polini parts to the kits like glixal, rolling wrench, malossi, stage 6, etc

@hesperidesbell4643 I'm going all the way to the top of the polini. The maddogs are slow with their big ass heavy golf cart wheel and tire. I could easily see a regular 50 scooter doing 55. I made my buddies go 53 with a skinnier tire but still stretched. It had a NCY 95mm variator for a DIO thar I customized to fit. I liked it better than the polini.

Worth a try at this point. LOL

@soqqiqi642 no idea. Every bike is different. Will you run a bigger carburetor or run the stock one?

My issue is the rpm at top speed is too low. It's nice everywhere else. The contra spring should not lower that. And it it did then I would be just holding in a lower gear which also would be slower.

@@GhettoWrench well I guess I thought we want our motors in the powerband as long as possible. Are you making most power at 6500 rpm? Lighter weights now to get you the rpm higher before they are fully out? I really don't know this stuff. It's all guessing and theory for now. Feel free to head up and help work on the dyno anytime.

Oh, and the white with green splashes looks clean. Very nice looking build.

@ThePitProductions I got thinking about what you said later and it might actually be worth trying. Like a manual transmission. Use a heavy contra spring to hold that shift till the rpms are higher. Hmm. I think I have a yellow one.

@@GhettoWrench I think the main thing to consider here is that it should not be A shift, it is a continuous variation of the ratio. The idea is to keep the engine rpm right where we want it. If it was 2 stroke you would make sure the bike was "in the power" as much and as long as possible.

@@Brujiito333 like a fuel computer or for timing?

@@GhettoWrench the 2

@Brujiito333 well fuel will not improve unless it is fuel injected and that costs too much for these cheapo bikes. An AFR will only help tune jet size and once that throttle is open all that matters is main Jet size and it is the only adjustable parameter. You will still adjust that for speed and not stoichiometric mixture so no improvement there. As far as timing, a computer can not advance ignition timing so again, once up to RPM you can only retard from a fixed mechanical point on the flywheel. These are sitting at 28 ish degrees so there is no advancement available.