[thomason2wheels]

Originally Posted by beatr911

Big Red now has just over 203,000 miles and runs like a top. I've been averaging just over 54 mpg with my commute which is about 10 miles at 40-50mph and the remaining 20 miles at 60mph, one way. This year I'm experimenting (again) with going as fast as I can without standing out enough to get a ticket which is about 70-75mph to see what the difference in mileage is. I think last time mileage dropped 4 or 5 mpg. The chassis and engine really feel in thier element at about 4500 rpm which is about 80mph. Top end is an indicated 125 mph which is limited by aerodynamics, or the 108horsepower.

Mods to improve economy are: advanced spark timing by 4 degrees, cut down stock windshield so helmet is just out of windshield disturbed air, warm air induction to airbox, dropped carb float level by 10mm, increased plug gap from .025" to .035", advanced exhaust cam by 7 degrees for more mid-range, used a 3/4" hole saw and drilled out the interior baffle in the exhaust (much better sound without loundness), synthetic oil in shaft drive unit, smaller EX500 mirrors, use approximately 132:1 of filtered used engine oil in the tank (because otherwise it's BTUs just thrown away).

Biggest improvement by far was ajusting the float level down. I gained about 7 mpg just from this. These bikes are known to run very rich and this confirms it for me. There is a guy in florida that makes a jet kit for it for about 50 bucks and all he does is lean out the rich spots to even out the mixture. I might do that in the future.

Gearing is bad on these bikes as well but not as bad as some. About 3600 rpm at 60mph isn't too bad but this is a 1000cc engine. The same guy as above makes a gearing change kit for these but to drop 600rpm costs about $450.00 and improves mileage by just under 5 mpg - really long payback on that one.

Live long and prosper!

Forgive what probably seems like a dumb question, but what does adding used engine oil to the gas do?