hi long time since i have posted here. sold an xr400 to my friend that had stood up in my garage the last couple of years my friend has spent a fair bit getting it sorted out and mot'ed the carb was all ****ted up and he had to replace a few bits in it as it was leaking petrol. the bike now wont start and he said it is blowing back air into the carb when its being kicked over? also the decompressor cable snapped. have you got any ideas what the problem could be hes saying something is wrong with the valves could be the problem. looks like im going to be getting the bike back as hes had enough of it letting him down.