Does it clear up every time if you pull off and stop for 1-2 min? It sounds more fuel related to me. If the electronics and spark were gonna break down I don't think it would continue to run at 40 or clear up when you slow down. I would look for a restricted fuel flow instead of no fuel flow.

 

I recently replaced the fuel tap with a pingle, it flows like a mofo. but you might be right, it could be at the carbs or mabey in the hose. I keep telling my self I need to run a fuel filter but I keep putting it off. Guess I'll yank the carbs today and see whats going on.

 

Those are pretty much the same symptoms my bike was showing - I'd get out on the highway and it felt like it was labouring... not getting the fuel. I couldn't keep highway speeds I had to travel the back roads. it worked nice at 40 mph but much over that and it started to miss all the time.

I found out my floats were way off and the bike was running obscenely lean. Might be something to check out.

 

I was going to suggest float level myself or maybe an obstruction. The bowls not getting enough fuel to keep you at higher speeds would do exactly what your describing, get the floats out and check that the passage is clear for fuel to flow and then adjust the levels.

 

I was going to suggest float level myself or maybe an obstruction. The bowls not getting enough fuel to keep you at higher speeds would do exactly what your describing, get the floats out and check that the passage is clear for fuel to flow and then adjust the levels.

you guys were right, I tore the carbs apart last night, and low and behold there was crud on the screens of the needle valves. also the fuel filter on there was looking a bit sad and crusty, so I replaced it, cleaned it all, and rode it to work today with no problems...seems to be starting in the morning way quicker as well