Modern Vespa

My gt200 is not running smoothly at highway sppeds. it starts well but is "jerky" when gaining speed. seems to have started this morning after i filled with gas. i swapped out the plug and added some sea foam but this has not done any good. is it a bad batch of gas? dirt in the carb? i did have the EVAP hose diconnected for awhile but i reconnected the hose after thisn problem developed.

the coild and cdi were recently replaced and since then, up until now, she has been running well.

btw, she starts well and idles well.

Please help!!

Worn rollers or variator surfaces?

is what i described a symptom? i put the malossi variator kit in about 4000 miles ago. could they be worn already??

worn maybe not.

but since its a new malossi kit... it'll be ideal to clean the transmission after 4000 miles.

i was told malossi and polini parts are good but generally wear out faster then stock parts.

How many miles on the belt?

The belt was replaced at the same time as the rollers/variator - about 4000 miles ago.

Weird that the problem would start right after I filled with gas.

How long since you replaced the fuel filter and lines? Art

I replaced the line and filter 2 years ago with the one sold on the Motorsport site.

Stopped by the local NAPA today to get a gas additive. The woman who waited on me said she has had about 6 people this week looking for gas additives for their cars. We all bought gas at the same location. So, I came home and drained the tank. Well, siphoned the tank until empty. I'll get some gas elsewhere and see if that makes a differnce.