ross it sounds like the fuel/air mix is weal ,this means there is not enough fuel in the mixture. These chinses bikes runs very weak from new to get through the strict eu emission limits,i would suggest this.take the throttle slide out of the carb and take the slide needle out from the middle of it if yoiu have fitted a cable tho the bike you will know how to do this,then you will see a circlip on the needle if it isnt already there take it off and move oit to the groove nearest the pointed end of the needle ,there will be about 4 slots.put it back together and see how it is..if its beeter then you can either live with it like that if your happy or if its a bot better but still a bit like it was before(cutting out on full throttle)then take the main jet out and either make it bigger with a set of jet drills or buy a larger one.so if you have for instance a 110 main jet then try a 115 and a 120,remember you can richen or weaken it by lifting or dropping the needle by moving the circlip.moving the circlip towards the pointed end of the needle richens it and the other way weakens it.good luck and let me know how you do please.
adam bike doctor, February 2010
