yamidonkey

nice 1 guys, now I know what its called I can phone the guy at the garage and make sure that he`s checked it. What is a Chinese 150 cc kit and how much if I do need one?

I have a yamaha ybr 15 which has had a new fuel pump and jet on it. I have had the bloke at the garage go round and round trying to get it to run properly for more than a few minutes but it keeps cutting out. He's convinced that it's losing compression somewhere but I have been told by somebody I believe to be knowledgeable that somewhere on the bike there will be a small black box with a spring in it and that if the box is knocked and the spring dislodged then this can cause the bike to keep cutting out does anybody know anything about this please