Cycle Efficiency Mod List

[Frank Lee]

Seriously I haven't had much luck modding bikes but then I haven't done much modding either.

I did gear up a chain drive CB450 with a larger front sprocket; engine was noticeably more relaxed especially on the highway but I don't have fuel logs or any memory of an fe increase. I always air bike tires up to the top end of the specs but not way over like on cars. I short shift and skip shift; accel briskly and cruise slow and steady and that's about it for technique. I've never gotten fe that's really spectacular on a bike. That Ninja on here with over 100 mpg, though, he's found some things that work.

[MadisonMPG]

Originally Posted by alohaspirit

the tailgate by that hippo almost looks like a grill!

lol I noticed that too.

[jonathan150cc]

-If you have a carburated bike, rejet the bike with smaller jets if possible.
(Too small and the bike won't run right.) On my scooter it resulted in a 17MPG increase.
-Full synthetic everything
-max pressure in tires.
-No hot rodding.
-Windshields help in a tailwind or headwind. They can hinder you in a crosswind.
-Taller sprockets if you spend much time over 55mph. If you live in the hills, this won't really do you any good. In that case, coast on as many downhills as possible (safe)

[Frank]

Make sure brakes don't drag and chain isn't too tight. Supposedly an X-Ring chain offers 25% less friction than a good o-ring chain. Slow down 5 mph.

[redyaris]

Most motor cycles have non existant aerodynamics so anything you can do to get improved aero dynamic is a good start. There are three rules for good aerodynamic round in front 1 in 6 taper towards the rear and a continues surface. The standard motorcycle brakes all three rules. So the first thing to do is to make the surface continues. I have done scale model wind tunnel tests that indicate that a smooth block of foam with only a rounded front and all other edges square and double the frontal area of a 12;1 scale model of a Yamaha WR250, has aprox 35% less drag! so you can see that a continuos suface makes quit a deferance.
On a sport bike with a fairing, fill up the space between the rider and the wind screen with as big a tank bag as you can. Install long saddle bags as close behind the riders lower legs as posible and cover all holes that have no utility. after you have done that change the finall drive to reduce rpm.
A good book to read on this is The Racing Motorcycle by John Bradley, in which he points out that a bus has better aerodynamics than the average motocycle. That is only because it has a continouse surface, all the bus surfaces are flat with little rounding or tapering. Craig Vetter provids great information as well, you can look at his 1980 - 1985 fuel economy contest on his web sit. The two up contest is the most usefull for the standard motorcycle.

[Jyden]

Put on a good faring....

[redyaris]

The Problem with most fairings is well documented by Craig Vetter in his dvd on how they got to 470mpg. The demonstation that convinced me that most fairings do nothing was the one about the naked KLR at the salt flats that only went 1/2 mph faster with a FIM racing fairing. Do you know of a fairing for a road bike that has proven aerodynamics on a modern road bike?

[Jyden]

The BMW r 100 RS faring is good, but it was also windtunnel tested.

http://www.bmbikes.co.uk/photos/phot...00RS%20(1).jpg

http://www.bmbikes.co.uk/photos/phot...%20(2)%202.jpg

[redyaris]

Thanks for the pics. Over the years BMW has done some interesting stuff on conventional road bike fairings and aero dynamics, and the fuel consumption figures they get for there bikes is better than most. As I am sure you are aware they have a history of aero dynamic projects going back over 7 decades. The Japanes bikes have not payed much attention to aero with some notable exceptions, like the hyabusa. Can you think of a medium 500cc motorcycle that has a well developed aerodynamic fairing?

[Jyden]

Only one of the midclass machine is the Suzuki Burgman - most of the others dosen't seem to be optimised for Fe or driver comfort, just looks.

I remeber Craigs farings well - lot of folks over here rode with those back then ( 1970 - 80).

We used many farings, Wetter vere good, but also Craven and rickmann was not bad. Mostly we rode full farings on long trips, and without having any numbers on it, it was always the guys without farings that had to go gassing up first - but maybee they just needed a rest from the windpressure.

We rode a lot of km's back then - a summer vacation trip was often 5 - 10.000 km round trip in europe, to grece via jugoslavia etc.

Today I've got a BMW R80s in the basement for a full restoration job.