Don't know what's wrong, but my bike won't rev over 7000rpm. It's got new plugs and a new k&n air filter. It's fine below 7000rpm, but just splutters above it!!
Had a similar prob only last week could possibly be not charging enough,found out this week then it packed up completely so i need a charge unit .What about fuel dirty, water in fuel (had that as well).Or does it seem electrical?