lance havana classic 125cc cuts out at 40mph

[smallville]

Scooter runs great until i get to 40mph. exactly at 40 it starts to cut out and I have to let off the throttle. Its suppose to go up to 59mph. Any ideas why it doesn't?

[sc00ter]

What year?
Fuel injection model?
Total miles?
Overall condition?
The Lance scooters are great quality products. Guessing kinda blind I would think.
Transmission damage of some sort?
Belt, rollers or clutch worn out?
If carb model, clogged main jet?
Unlikely, but a stator starting to die?
Wheels spin free when off the ground?

[smallville]

2014 carburated. 6000 miles and in great condition.
I checked the transmission a few days ago thinking it might have a spacer like the restricted 50s do. It didn't. Belt, variator and roller all seemed in very good condition.
But I did notice that the kickstarter was not moving at all (I've always just used the electric start).
Carb maybe? But at exactly 40 mph every time? I guess I could take it off and clean it. Probably a good thing to do anyway. I'll do it Thursday or Friday and report back. I'll check the wheels too.

[sc00ter]

I'm not sure were the carb is mounted on your Lance but if you can get the float off without removing the carb, you should be able to remove the jets as well. But even if you have to remove the carb, please note:

1) Be careful removing the float bowl. It will sometimes stick, you will get rough with it and catch the float getting the bowl off. If you bend the float you'll have to reset the float height. Its something I stink at.

2) Pull the jets and soak them in an ultrasonic cleaner like a jeweler uses. Don't go poking metal wire thru the jet holes as you can mess up the flow. Ultrasonic cleaners are the best way. Harbor Freight has them for around $100. I use a few drops of Dawn dish soap and distilled water.

3) Check the float height while the bowl is off. Its rare that they get out of factory adjustment but it can happen.

4) If you do the carb first and the problem persist, check the stator output. Again, very rare on a Lance. Plenty of You Tube videos on testing stator output.

Keep us posted. I'm thinking/hoping it's something simple.

5) Lastly, check the spark plug. Look at the electrode end for any contamination and make sure the plug boot fits on completely and tight.

[sc00ter]

I just thought of this because I had a car that did this nonsense. Vapor lock! My old Impala would be driving along and start loosing power. I'd let off the gas and it would drive normal again. Played this game for a bit and pulled over. When I removed the fuel cap I heard a whoosh noise. It got so bad in the end I had to use a channel lock wrench to remove the gas cap! I ended up having to drill a tiny hole in the cap until I would fix it correctly.

[smallville]

I took off the carb , took it apart, cleaned it but no difference.
I guess I am going to look for those videos on how to check the stator output.
I am also going to get a new spark plug wire because the one I am using right now is from a car (but the problem already existed before I had to use the car one).

[smallville]

Checked stator. All good. Got the right spark plug wire and boot.
....still having the same problem.
Any more suggestions?