Buddy of mine has the V twin Ascot...runs fine around town. At 60 mph and above, the bike shudders and craps out. Every time. Below 60, ride it all day. Above? It stalls and he has to pull off the road and wait ten minutes til it cools down and then it runs fine. He checked the following: Coils (new) Carbs (cleaned) All hoses (checked and double checked routing) Left to do as far as easy stuff: Plugs Gas quality/freshness Any ideas?