Hi,
Just want to follow up on what happened to my scooter. I ordered a new Dr Pulley variator set, but it did not cure the problem. I also checked the wiring and the electric components, but no change there either.
I took the scooter to a local mechanic, who specializes is scooters, as the Kymco dealer was clueless. It took him half a day to figure out what's wrong with my bike. He checked the drive train, adjusted the valve clearence and engine timing. Then he took a look at the spark plug... It was all white. He disassembled the carburetor and immediately noticed that the stock main jet was replaced. The part installed was probably from a small scooter with a part nr "KY B6". He replaced it with a standard piece.
Why the previous owner did something like that is beyond me. I bought the scoot from a dealer, so I can't talk to the guy.
My scooter works fine now. With the Dr Pulley set up it really flies and no longer feels like an underpowered 150cc bike. I'm all happy now
I hope it may help some people who have problem with their scooter. I was told that the GY6 engine is bullet proof, but very sensitive to fuelling.
Thanks for all the help and info. I have a much better understanding of scooters now.