It said it all in the subject line. I bought this bad boy 2 weeks ago and changed the oil and plug trying to solve some other issues. There is a almost whining or grinding noise comming from the ac generator. Also while at full speed it seems to push and pull the whole time? Anything?
A lot of A50's do give off a kind of whirring noise at top speed if deresrticted, seems it normal, unless its a bad sounding noise that soumds like its causing damage that is..
The surging could be a lot of things, Incorrect jetting, bad CDI, worn rollers or belt, rollers too light, dirty carb/jets, torque spring too heavy or worn, or a host of other things. Best to strip down the CVT totally and check all parts for damage or wear then clean all the components 1st before fitting it all back in, see if that helps.