hi patrick, i´ve recently become the proud owner of what can only be described as the finest engine kawasaki ever made. i had one fifteen years ago and regretted selling it ever since. in answer to your question, as the engine is so solid, i would look towards the carb myself. the only problem i´ve ever found has been with the diaphragm. tiny,(and i mean tiny) holes appear at the creases, and upset the mix. if replacements cant be found, treat as per a puncture repair, ie rub down surface, apply glue, but then leave to dry and then apply french chalk. also double check all jets. some of the holes are minute.