MZ Moskito 125

Mz Moskito 125rx

Post by richiekunz on Oct 10, 2011 9:11:57 GMT -5

Hey I’m new to this forum and with my scooter too.

Post by Goosey on Oct 10, 2011 9:35:06 GMT -5

Post by 90GTVert on Oct 10, 2011 14:35:58 GMT -5

to the forum. He’s posting in the right place Goosey. That should be the 125cc version of the GY6 4T. I wish they did make 125cc 2Ts like that, but that’s another story.

You could start out by just making sure the carburetor and CVT are in tune. For the carb, you would want to have a look at your spark plug and see if it appears to be running rich or lean. If it’s been in there a while and it’s pretty much white, you might want to try a larger main jet.

If it’s dark, like black or brown it’s probably a bit rich. Before going down on main jet size I’d suggest installing a new spark plug and taking a ride, staying wide open as much as you safely can, avoiding idle and low throttle positions. Right before you get home run it WOT and hit the kill switch to coast in if possible.

Then take a look at the plug. You can also tune the main jet by swapping them and seeing what feels best and gives you the best RPM. That’s the way I tune most of the time, but if you don’t have jets around right now you can try the other way.

After that, I’d adjust the idle mixture and speed as shown in the link below. If throttle response or part throttle feel are off, try changing needle clip positions. If response is good and you don’t notice anything odd at part throttle, leave it alone.

Once the carb is in tune, move on to the CVT. To keep it simple, on a stock scooter I would consider 2 things. Clutch springs and roller weights.

Clutch springs. If it feels sluggish on the very initial takeoff, you might try stiffer clutch springs. I can’t say I find this to be a problem on the stock 150s I’ve ridden (never been on a 125 GY6).

They seem to make enough torque that they get moving pretty well with the stock springs, and I’m a big dude. If you feel you could benefit from more engine RPM off the line, you can replace the stock springs. They commonly come in 1000RPM, 1500RPM, and 2000RPM variations.

The names imply how much higher you will have to rev for the clutch to engage over stock, not the RPM the clutch will engage.

Roller weights. If you can get moving OK on the initial start, but it seems to rev to high or to lack RPM to accelerate quickly you may want to try different roller weights. Lighter weights will increase RPM, heavier weights will decrease RPM. Too light and you will rev past your engine’s powerband and lose top speed and even acceleration if you go really light.

Too heavy and it will bog down and feel sluggish.

If you’re looking more for what you can do to make it faster beyond just getting in tune, my first thought would be a big bore kit. Normally I don’t think big bore kits are good for a big gain on the 150s because they can’t get much bigger without needed case machining. Since yours is a 125cc, you can gain quite a bit of displacement I believe. The GY6 cases will only fit 58.5mm or 59mm kits at the maximum. The 150 starts out at 57mm so it’s not much different.

Your 125 starts out at 52mm bore, so you can gain a little over 30cc with a 58.5 or 59mm kit. If you plan to go this route or do other performance mods like exhaust or air filter you will probably need to retune the carb and CVT along with those mods.

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