Whilst out on track yesterday in the first session my sons bike kept cutting out and stalling. The track conditions where wet and muddy, we were the first out on track and it was thick! By the time i noticed him sat track side looking sorry and i got to him he had drained the battery trying to get it started, so after getting the bike back to the van and leaving it for 30 minutes and finding a jump start pack to get it going this is what we found. These statements best describe how it ran sat on the stand. losing power on full throttle. spluttering and cutting out. cant hard rev, cuts out. poor idle cutting out and lumpy runs ok on light throttle, cuts out on hard throttle. Now, i know very little when it comes to 4 stroke bikes and a little bit more on 2 strokes but i do have the internet to help. So what could it be and where should i be looking first. I`m looking towards a clogged injector maybe? blocked fuel screen/filter? knackered fuel pump? am I on the right track here and what other suggestions can you guys offer? Cheers Tom.