My 426 is running terrible. The bike is sputterring (running rough)and it actually backfired when I shut it off the last time I took it out. The rpm's seem to surge while idling (rough,good,rough,good). It seems to get worse the longer the bike runs. I changed the plug and this really didn't help. Everything on the bike is stock (jetting, exhaust etc.) I have done the blue wire mod. The coil lead popped off of the plug cap when I was changing the plug. I put the coil lead back on and everything seems to be ok. I would think that it is a relatively simple problem based on the fact that this happened overnight. Took the bike out and it ran great, the next time I start it I have this. I'd appreciate any help.