Because my spark plug still reads my mixture is still lean, but I "tuned" the carburetor per the above instructions. Do I just need to turn the mixture counterclockwise an 1/8" of a turn, ride around a little bit, and check the plug to see where I'm at?

its always good to start with a new plug but yes to your answer.once you get it in tune use your plugs u used in the past for testing.

a lot of people on here don't use after market filters cause of problems you are having.read about how they put tape on them to make it richer.when you turn your screw you have to wait to see the engine rpms change.i always turn to the left and when rpms go highest I turn to the right same thing and put it in the middle

turn the mixture screw CLOCKWISE an additional 1/8 turn, then run it for a few days and "plug chop".

You're looking for a nice brown coffee color on the WHITE CERAMIC INSULATOR directly under the spark points.

Turning the MIXTURE SCREW COUNTERCLOCKWISE LEANS the MIXTURE.

Gotcha. I'll try and retune my carb... And it could possibly be an issue with too much air either way because of the filter, so if I don't get results by tuning the carb I'll start removing surface area from the air filter.

This is frustrating business for sure!

Okay another question, specifically a CVT questions: I'm looking to squeeze another 10 MPH out of this thing (right now it cruises at 40-45). How might I go about doing this? Changing the roller weights? Clutch springs? Using a kevlar belt? I heard the A9 cam increases top speed. Thoughts?

You're in break-in, do not try to ride faster than 40mph. ESPECIALLY with a Bbk. People argue w me about break in, but trust me I speak from experience, for the first 800 miles, vary your RPMs constantly and evenly. Only hit maximum for LESS than five second at a time.


Then, after break-in, get a KOSO-style variator w 6g flat-sliders and red-spring clutch. A Kevlar belt is a good plan as well.

It is possible that you may need to restrict the filter. I use paper cone filters and electrical tape.

Noted. I'm trying to vary the RPMs as much as I can, although I still drive it on the daily. So far so good.

I don't have an impact wrench to get the nut off that holds the variator and the clutch on. Any suggestions?

Yes go get one of these, and pay the 6 bucks for the no-questions asked replacement plan.

http://www.harborfreight.com/12-in-e...nch-68099.html

That's what I use.

I'm going to check the plug tomorrow after a WOT run to see where my mixture is.

Current planned CVT upgrades: performance variator with 6.5g roller weights (not sliders, only because I already have the roller weights), kevlar belt, and performance clutch with red-springs.

My engine is 139QMA, so it's essentially the same as a QMB, but it fits 12" wheels, so it requires the longer belt. Anyone got a link to a good kevlar belt that'll fit a QMA?

http://www.scooterbelt.com/

http://www.partsforscooters.com/Street-Scooters-Belts

Awesome, thanks for the link.

So I'm just a little confused. I do all these modifications, and my top speed is still 40-45 MPH. Am I missing something? My friend's stock 50cc GY6 scooter s just as fast as mine (although my acceleration is quite better). Is it the gearing? I want it to cruise at 50 MPH comfortably. That's my goal. And I'm not even that big either - 6'2" and 180 lbs.

Any ideas?