Yamaha PW50 Help will not start! I have cleaned out the carb (all jets), cleaned air filter, new oil in case, and new oil injector tank, new plug, new choke cable. Bike only starts when exhaust is off the bike after 10-20 kicks. With the exhaust on it does not start at all. I have just used a plumbing snake to clear out the carbon from the head of the pipe into the expansion chamber but it still doesn't start with the pipe on the bike. Does the pipe need to be cleaned out more of Carbon and if so how do I do this with out a BBQ? can I use a hand held blowtorch? if this doesn't work what else should I check? Will the bike not start if the oil injector not supplying oil to the carb too? I have that next on the to do list to clean out. But it does start up when exhaust is not on.