Alrighty then, I think I might have some useful suggestions and cure for your oil pressure drop. 1, because you are running alcohol [about twice the volumn amount as gas]and forced induction the volumetric efficiency is way above 100% and fuel is getting forced past your rings, diluting you oil, and washing the cylinder walls with the dilution causing the drop in oil pressue. Because of the length of the course[5miles?] and the amount of running time required to cover the 5 miles, the oil dilution is becoming critical at approximately the 3 mile mark. Some obvious cures may not work in your case because its a bike with a pretty slick aero package already so we don't want to disturb that setup. First thing I would do is perform a leak down check on each cylinder. Anything under 95% I would check to make sure it wasn't the valves, then go after the real culprit, the cylinders and rings. You stated in your opening statement that the main bearings,crank and rod bearings were not showing any ill effects because of the oil pressure drop. Correct? Even so I would check to see if the clearances of mains,rod, and crank were on the low side of the acceptable tolerances for your engine. I would then take a hard look at the cylinders. Check to see if there is any scuffing on the piston walls or the cylinders. Pay close attention to the thrust side of the pistons and cylinders. The way cylinders are prepared in todays technology compared to the "old days is so vastly different, because the top builders have developed a way to get the cylinders as close as they humanly can to a perfect cylindrical shape. I think that is the key in your situation. It would also be nice if you would be able to increase your oil capacity and work on the vacuum deal,if possible. I am going to send this now, I see you are on line, I will follow in a bit with my suggestions on cylinder prep or if you think what I have put forth is BS, just say, STOP your nuts and of course I will go back too lurking. Later Mike R.
