Okay, I have had another post about this bike. While I am still solving one other confusing issue, I though I would try to solve this. They seem to bear little effect on each other. Bike hate starting on choke, just dies, maybe being flooded. Will always start first time without choke, engine was from a bike that had been left a few years so *sometimes* needs start ya' bastard to get running. Once running it's fine. The problem is that it wont hold a stable idle speed. I set it to the factory 1400rpm and it will suddenly rev to 4000 or so and just sit there, I screw the idle back again to 1400 and it will run, then stumble slowly and die. I have cleaned the carbies and there is no sign of oil coming up to the air box (the cause of this issue on my last bike). Any idea's? Is it a balancing issue or idle screw issue or one/both of these?