on my 07 66 tooth rear pulley i did worse in 6th than 5th at 65 not enough power at that low rpm, my 15 with a 68 tooth does about the same at 65 5th or 6th. at 80 either bike sucks down the fuel.

 

The "hockey" in the game here is a combination of available power and how much of it is being needed. Up to the horsepower and torque peaks, the lower the rpm, the lower the available power. Temporarily disregarding that the engine will destroy itself, there is less power available at wide open throttle at 1000 rpm than at 5500 rpm. When asking for more than about 70% of the power available at a given rpm, the mixture is changed to power enrichment mode, a little extra gas for a given volume of air. If at a given speed you are just below the power enrichment threshold you will achieve a certain mpg figure. If you re-gear to a lower rpm for that same speed you will go above the threshold to activate power enrichment and your fuel economy will take an out of proportion dive because of it. I would hope that the factory engineers try to set up the bikes so that normally anticipated cruise speeds are achieved below the power enrichment threshold and fuel economy benefits. Go above that speed and power enrichment kicks in and economy drops significantly. I suspect that 80 mph is above the enrichment threshold, my fuel mileage at that speed suggests I am above the threshold and I get mid 30s.

 

My Glide is much older than most in here and a carb one at that. Our batwings (and I suspect the sharks as well) are like barn doors, so when pushing the cruising speed up, the drag goes up at a much greater rate, hence demands far more power from the engine.

I have access to German autobahns, where speeds can be far higher than most other countries and cruisin' at 90+ mph can empty a tankful in super quick time. Best not to bother working the mpg out!

 

Makes sense. I have a 110 with 255 cams so I have plenty of torque from 1500+ rpm. If it wasn't so damned expensive to change the belt and rear drive I would try it just for ***** and giggles to see what a difference it would make.

 

The Baker DD7 has lower and closer gears1-6, 7 is 1:1, same as the 6 speed cruise drive.
As far as gas mileage,late model Harley's are geared a bit high( softails and dyna's are very high),even going to just a 31 tooth sprocket is worth it.
If you ever have to go into the inner primary,throw a 31 tooth pulley on while you're in there.

 

This is what I did. I have a pretty good running 107, This thing loves running down the road. Pulls awesome.

I get 37 MPG fully loaded (tour pac) two up and cruising at 75 MPH. I can get 40+ MPG solo.

And it is a blast to ride. It's always temping to goose it just for the fun.