stumbling

So my 81 400 special will run and take off like a rocket in town but on the highway in 5-6th gear around 4500-5k rpm it boggs down and I have to drop down to 4th and get back up to 50mph and ride it out. I feel as if it's either not getting enough air or not enough fuel. If I hold the throttle...

My bike Molly acted a little funny on a recent night ride. Loss of power, stalling, stumbling...etc. Now my buddies have been gearing up for a LOOOOONNNNNGGGGG ride, a three gas-up ride at least! And they wanted, of course to have me go along. But the night before I have this bad feeling...