Question about motorcycle mpg

[northboundtrain]

I was looking at motorcycle mpg on this site http://www.totalmotorcycle.com/Motor...uide/index.htm and I'm curious why fuel economy is relatively poor compared to that of a car. For instance, several of the honda 750cc models get approx 45 mpg. Now a car that's several times heavier with twice as many wheels (greater rolling resistance), a much larger frontal area, and an engine twice as big can get the same mileage.

Based on the car's fuel economy, you'd expect a motorcycle with an engine half the size and much less rolling resistance and smaller frontal area could do much better.

Are motorcycles tuned drastically differently -- like for high revs and hp? Can they be re-tuned for improved fuel economy?

[red91sit]

it's actually a lot of little things acting together.

They're definetly geared different, and more towards acceleartion than cruising (exeptions like Harleys of course) For example, my bike runs a good 5500 rpm's at 60 in teh highest gear.

Aerodynamics aren't very great on a motorcycle either. The air gets VERY dirupted by the rider, as the only place it is ever attached is the very front of the bike. The very small frontal area helps this a lot though.

The tires are much smaller, with less contact area. But they're also MUCH softer. The average motorcycle tire only lasts thousands of miles, not tens of thousands.

There is DEFINETLY room for improvement, as Craig Vetter has done a GREAT job of proving.

[QDM]

You are correct about most motorcycles being tuned differently and running higher RPM. My old Honda CX500 puts out 50 hp, redlines at 10,000 RPM and gets about 45 mpg. On the freeway it's turning about 6000 RPM. My Suzuki Swift car turns about 2500 RPM on the freeway and gets better mileage than the bike.

Some small and slow motorcycles get very good mileage, like the 50cc or 70cc Hondas used in most third world countries. They'll do over 150 mpg.

Q

[Bill in Houston]

The aerodynamics are really bad. A Metro probably has less aero drag than a person on a motorcycle.

Plus they are tuned for performance instead of economy.

[ELF]

[quote=northboundt

Are motorcycles tuned drastically differently -- like for high revs and hp? Can they be re-tuned for improved fuel economy?[/QUOTE]


They can be tuned for economy, much easier than most cars. Almost all bikes have carbs with changeable jetting, also very easy to change the ignition timing.
If you had some mechanical skills you coud also play around with cam timing or with different cams to change the power and torque to lower rpm range.

[MetroMPG]

Not to mention a larger rear sprocket. This was an aftermarket option for my Ninja 250 (14k redline!).

[MetroMPG]

BTW - this same question came up in a previous thread...

Motorcycle mileage

[ELF]

Originally Posted by MetroMPG

Not to mention a larger rear sprocket. This was an aftermarket option for my Ninja 250 (14k redline!).

Ah yes, I forgot about that. Also very easy to change gearing on bikes compared to cars.

[Bill in Houston]

I think you would want a smaller rear sprocket to reduce cruising revs.

I always wanted to hear one of those Ninja 250s hit the redline. Had to sound like an F1 car...

[northboundtrain]

Thanks for the replies. Sorry for posting in the wrong section. Wondering if there is a good bike anyone can recommend that has high FE potential and still enough power to get out of a jam if necessary. Also, parts should be available and plentiful. I did buy an old Suzuki GS400 a little while back, planning to fix it up, only to find later that engine parts were not available for a rebuild. So I sold that one and I'm toying with the idea of getting another. Thanks

[beatr911]

Kawasaki Ninja 500 and 250 have both have a production run of like 15 years and there is good aftermarket support as well. Parts availability is good, they are cheap, and they get good FE. Motorcycle Consumer News got 64 mpg with the 500. They have changed little over the years so a good old one is virtually the same as a newer one. For some reason I like Kawasaki, they usually get good FE for the power and the have more "personality" than refined Hondas that don't get as good FE.

[SVOboy]

Is the ninja a 4stroke?

[Bill in Houston]

The Ninja 250 was a 2-stroke. Not sure about the 500.

[SVOboy]

Oh, well, I was thinking about one (since I want to get a bigger bike at some point), but I won't consider any 2-strokes.

[Bill in Houston]

Lots of good 4-stroke 250s to choose from, I bet. This one came to mind.
http://motorcycles.about.com/od/road...rebel250rv.htm

[cfg83]

Bill -

Originally Posted by Bill in Houston

Lots of good 4-stroke 250s to choose from, I bet. This one came to mind.
http://motorcycles.about.com/od/road...rebel250rv.htm

Yay, the Honda Rebel!

honda_rebel.JPG

I loved the first commercial in the 1980's with the Nails "Let It All Hang Out" background music :

No parking by the sewer sign
A hot dog with a razor broke
Water dripping up the spout
But I don't care
Let it all hang out, hey!

CarloSW2

[SVOboy]

The Rebel is actually what I was looking at, for down the road.

[Ryland]

the Ninja that I took for a ride a few years back was a 4 strok twin, as far as I know they wer alwas a 4 stroke twin.

[Bill in Houston]

Sorry. I was wrong...

[James]

Honda also made a 250 nighthawk for a while, I think it gets 70-80 mpg...it must be a very similar engine to the rebel, and might have better aero. Thats what I am after.
My friend has a 450 nighthawk 1982 and it got 67 MPG when i took it for a cruise last summer. It is fairly fast, faster than most cars under 60mph, and has a 6th "overdrive" gear. The revs at hwy speeds were actually much lower than my old yamaha xs1100.

[Lug_Nut]

The 1982 Honda CM450E I had would consistently better 65 mpg at sustained highway speeds, but was a bit small for comfortable fit on long rides. I bought an 81 GL1100 GoldWing (with Vetter aftermarket fairing) that returned mid 50's. I then fell in love with the GL1500 and it's silky six, but that one "only" returned 45 mpg. I sold that one for the cash to buy my Sonett.

[SVOboy]

Honda still makes the nighthawk, , just for information's sake.

[slurp812]

Originally Posted by Bill in Houston

The Ninja 250 was a 2-stroke. Not sure about the 500.

Ninja 250 is a 4-stroke.

I have a 1984 RZ350 Yamaha, now thats a 2 stroke. at its best it may get 35-40 mpg. Wont even think of hypermileing that....

[MetroMPG]

Originally Posted by Bill in Houston

I think you would want a smaller rear sprocket to reduce cruising revs.

Whoops. Right you are. I get confused sometimes...

I always wanted to hear one of those Ninja 250s hit the redline. Had to sound like an F1 car...

http://www.youtube.com/watch?v=HV0-RtbUty4

[MetroMPG]

I see Honda's now offering a CBR 125 cc bike:



With a 1 cylinder 4-stroke. 13 hp... Oooo!

[MetroMPG]

Originally Posted by slurp812

I have a 1984 RZ350 Yamaha, now thats a 2 stroke. at its best it may get 35-40 mpg. Wont even think of hypermileing that....

I came very close to buying that instead of the Ninja 250. Guess I made the right choice in hindsight (regarding FE, I mean).

[SVOboy]

Link to the cbr 125?

[slurp812]

Originally Posted by MetroMPG

I came very close to buying that instead of the Ninja 250. Guess I made the right choice in hindsight (regarding FE, I mean).

YES, 2-strokes are not as environmentally friendly. but bang for the size is off the charts...

[MetroMPG]

Originally Posted by SVOboy

Link to the cbr 125?

Is google broken?

Try: http://www.bikez.com/motorcycles/hon...125_r_2006.php

[SVOboy]

My google is set on japanese...and honda doesn't have it listed,