Hey guys was wondering if you could help me, I have bought a 2003 450r supermoto converted. It had been garaged for a few years and when I got it it would run all lumpy. So I put a crab cleaner through it a new filter fresh fuel and a spark plug. It has started to run better but On a short motorway run at 70mph after a minute or so it will start spluttering as if I'm on and off the throttle, even when you drop it down a gear and when you pull over it just cuts out. Was wondering if it would be a carb issue or maybe a bad ignition coil or something? Thanks.