hi graham, sounds like you may have a fuel problem. pull the fuel lead off the petrol tank, make sure there's juice coming out. if thats ok then check the carb, you may have to strip & clean it. check the float level, make sure the carb is filling up with fuel. next have a look at the air filter, it should be clean. make sure you've nothing obstructing the air box & air is getting through the filter. bolt everything back together, stick a new spark plug into it & see how it goes. if it's still not going then post another message we'll help you out.
steo
June 2009