Hey Gordon -
This is mostly about long distance travel for me. My VN can physically cruise all day long at pretty much whatever highway speed I like (and is safe.) However, the range tends to drop as it gulps more fuel. I have daydreams about traveling through the NW and don't want to get stuck in the middle of nowhere.
So I'm generally curious as to ways to extend my range. I.e., more MPG at "travel speed," as opposed to more MPG by driving the bike at 52 on the highway. 52 is decidedly unsafe in many areas around here as traffic can be cutthroat on the freeway.
Fuel economy is a bit better with the 170, in the sense that I can cruise at highway speed at lower RPMs, and thus extend my range. It's maybe a 10% difference? Tops.
So, anyway, it seems if I want better MPG, I can either look into ways of fairing the bike or changing the gearing.
Fairing I'm considering - there's actually not a lot of work out there about true aerodynamic fairings. Most marketed fairings just seem to be about rider protection and/or reducing buffeting on the rider. But that's for another post I think. If there was a way to make our bikes more aerodynamic I might go back to the 150 rear wheel - it'd be quicker to speed than the 170 but (faired) would still be faster than stock because it wouldn't be pushing so much air.
But back to my final drive musings. I know that if you want better MPG on sprocket bikes you can change the rear sprocket to a smaller one. This sacrifices low end torque but allows the engine to rev lower at higher speeds.
So I was just wondering if there was an analogue for our bikes. I know people had talked about adding a sixth gear and how complicated that would be. But what if the final drive/rear wheel was replaced by another shaft driven bikes? That other shaft driven bike might transmit the power from the spinning dive shaft in an entirely different ratio. If there was one, it might be a more fabable swap than messing about with the bevel gear. You'd just have to mate up the new final drive/wheel with the shaft on our bikes.
Anyway, I'm home, my taxes are done, I got good outcomes for my clients today, so I'm going to have a glass of wine and relax.
MF Battery, Iridium Plugs, RR relocated, Voltmeter, 170/80/15 Kenda Kruz rear tire, DIY Samsonite hard bags, DIY shaved seat with Beaded seat pad ('cause that's how I roll) and the dreaded STATOR CHANGE.
Shining Black Bess '86 VN750, retired for parts after a fried stator and being knocked (kee-runch) in her parking spot.