Slow acceleration from dead stop

[CamaroMan79]

Over the last year my Agility 125 has had a problem accelerating from a dead stop.

I Have to give it full throttle and it takes off slow then gradually speeds up.  After I get to 20-25mph I can let off the throttle and give it throttle again and it accelerates fine.

The scooter has 3,100km.

I took it to a shop last year when it first started doing it and they replaced the belt which was pretty worn (they said this was unusual for the amount of miles).

The belt change helped some, but the scooter still doesn't accelerate from a dead stop like It did when I first bought it.

What could be going on?

Its not an air filter problem because I have changed that with no difference.

Could it be that the belt needs to be tightened more?  It does not feel like the belt is slipping(I did feel it slipping before I had the belt changed) but it hasnt slipped since the new belt.

[Cortez]

I'm gonna vote for carburetor clean-up, this doesn't sound like any belt related issue,
and yeah, it's very strange the belt was worn at that mileage. Are you the first owner
of the scoot?

Maybe someone messed with it before..

[CamaroMan79]

I'm gonna vote for carburetor clean-up, this doesn't sound like any belt related issue,
and yeah, it's very strange the belt was worn at that mileage. Are you the first owner
of the scoot?

Maybe someone messed with it before..

Yes im the first owner, Its a 2009 and I bought it new in 2010.

How would I go about cleaning it? Take it off and clena it with carb cleaner?

[zombie]

Are the rpm's high or low when it struggles?
The carb clean is a must, unless you have other chemical means (soak time). You'll Really thank me if you get these at the same time/store...
http://www.homedepot.com/buy/plumbing-torches-soldering-irons/lincoln-electric-tip-cleaner-oxygen-acetylene-torches-117469.html

They are like 6 bucks there. Do it like a dental cleaning Pick into everything, and use the carb clean to blow out EVERY hole in it. Force the cleaner thru all the openings. Get 2 cans now that I think about it. You Have to remove the jets/float&needle to thoroughly clean it so keep track. Count the turns on the mix/idle screws to have a "base" setting. (They Must come out too)

[Cortez]

Yes im the first owner, Its a 2009 and I bought it new in 2010.

How would I go about cleaning it? Take it off and clena it with carb cleaner?

I wouldn't do anything, I'd let my dealer take care of it as they already did (on the A125).
 

[OregonDad]

Replace the clutch springs with stiffer ones to give you higher RPMs at launch.