Building a streamlined hypermiler

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I don’t know if you guys remember the Craig Vetter annual fuel mileage competition, but I got to thinking about it today and started wondering what it would take to build an extremely high fuel mileage motorcycle , simply as a technical exercise. I’m quite sure they aren’t much fun to ride, but I find the science behind it interesting.
Here’s one mans vision. A fully streamlined Honda 125 that gets 214 mpg.

https://ecomodder.com/blog/diy-aero-fairings-honda-125cc-motorcycle-214-mpg/

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I'm impressed! I figured that mileage number was obtained at some completely impractical speed like 15mph or something.
Not my cuppa tea, but I can appreciate the thought and engineering that went into it.
 
Hey Mick! Good to see you buddy, you still riding that big ole Triumph? :)


I’d do it on this drag bike that came into the shop, has a Vetter stamp all over it, dunno about miles per gallon, but you’ll have fun getting there......assume the position


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Somebody turned a Hurricane into a drag bike? Sacrilege! :eek:
 
be an interesting ride with a cross wind.
yeah an MC is a poor place to start for fuel mileage it's all about cheating the drag; knees elbows head sticking out, makes for a lot of drag. A 3000 pound Prius' can equal an XS650's fuel mileage.
Hoinda CTX700 tends to get 60-70 MPG ridden at typical legal street speeds.
 
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I was diving into that Craig Vetter website and reading about the guy that pushed mileage to the record. Over 470 mpg on a streamlined Honda XL125. I got the feeling that the Honda factory got involved with the winner. The engine had many internal mods, longer stroke,
Lightweight valve springs, running extremely thin machine oil, transmissions modifications and on and on.
 
The green bike in the first post, the front end slides forward for entry / exit , and I believe the bottom is open so he can just put his feet down when coming to a stop. That open bottom , I’m sure, creates some drag, but overall very efficient.
As Gary mentioned, it would probably be a little dodgy riding it in a cross wind! :yikes:
 
Blurring the lines , three wheelers.

Mercedes Benz
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Toyota
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Chinese ?
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I was trying to find an image of something I saw in person once. It was a small production run of what looked like a wingless airplane powered by a motorcycle engine. It was two passenger , they sat fore and aft, with an enclosed cockpit and slide open canopy. I knew a guy that had one.
 
Part of fuel consumption is what's needed to just run the engine.

Suppose that you regear your XS2 for 3,000rpm @ 55mph.
Put your XS2 on the centerstand, in 5th gear, run the idle screws up to 3,000rpm. How much fuel does it burn in an hour? That simulates 55 miles. 55 / (fuel consumed) would be your mileage with zero rolling/air resistance. Of course, an unattainable value, but gives you an idea of where the limits are.

Unfortunately, our 256 engines have their poorest BSFC at 3,000rpms, about 0.62 lb/hp/hr.

The best BSFC I've seen was about half that, 0.3 lb/hp/hr, on the swash-plate engines...
 
Waiting for the Tasmanian corrective surgery before returning to the North Gedub, will have to do a finger count before leaving for the big island (Australia) thanks for the pardon too....

Mick
 
Waiting for the Tasmanian corrective surgery before returning to the North Gedub, will have to do a finger count before leaving for the big island (Australia) thanks for the pardon too....

Mick
Forget the fingers mate................count the heads
 
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