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Most fuel efficient RPM on bike
James - 4/8/10 at 06:31 PM

Girlfriend's Polo gearbox is knackered so she's commuting 65miles a day on her Suzuki SV 650 till she gets a new car.

It's costing her a fortune in fuel and she'd like to know the most efficient RPM.

I know with petrol cars it's 2500-3000rpm that is the most efficient- or so I've read and once heard on 5th gear).

What would it be on the bike? The same? Or proportional to the rev limit? So about 5-6000rpm?

Thanks!

James

cd.thomson - 4/8/10 at 06:34 PM

genuine question - are 600cc bikes bad on fuel then? It's relevant to my current plans!

matt_claydon - 4/8/10 at 06:40 PM

It's far more about road speed. Aero is horrendous on a bike so you want to keep down to not much more than 50 mph, it all starts to go bad above that. It doesn't really matter what RPM the engine is doing at that speed but you'd want to be in 6th gear to keep the revs as low as possible, once you're out of the inefficient area at very low rpm, higher engine speeds generally just mean higher frictional and pumping losses within the engine.

omega0684 - 4/8/10 at 07:02 PM

a 65 mile commute, jesus, i thought mine was bad at 50!

smart51 - 4/8/10 at 07:12 PM

Engines generally have their lowest specific fuel consumption at a speed a little below peak torque. The spread of the SFC curve is quite flat so a 1000 or 2 either way of optimum is still good.

Keep it in top gear and don't go too fast.

jossey - 4/8/10 at 07:48 PM

i know you will think im a div for commenting. but i have to.

i have internet for the first time in 2 weeks and i wanna say...

your answer is 0 RPM lol

ok sorry. 1500 rpm is very fuel efficient...


dave

RIE - 4/8/10 at 07:48 PM

quote:
Originally posted by cd.thomson
genuine question - are 600cc bikes bad on fuel then? It's relevant to my current plans!


Depends on the 600 I suppose - the fact the SV is a v-twin doesn't help compared to an I4

Rallye_Mark - 4/8/10 at 07:49 PM

An average rule of thumb is about 1/3 of the engines maximum RPM and at 1/3 loading.

Obviously the load will depend on the speed of the vehcile due to resistances but thats what i found when doing engine testing on a rig.

Stott - 4/8/10 at 08:07 PM

My SV650S carb and SV650 FI both mega miles to the gallon, 50mpg all day and 60mpg sometimes on certain runs. The S was better due to the full fairing it had but both of these were treated pretty normally I'd say, speed varying from 60 to............ on motorways etc in 5th or 6th gear, if it's really much worse than that on a run I'd get it looked at

Unfortunately though smoothness and anticipation are the key to fuel economy and you can't just tell someone how to do that overnight

HTH
Stott

mcerd1 - 4/8/10 at 08:17 PM

what sort of MPG is she getting at the moment ?

quote:
Originally posted by omega0684
a 65 mile commute, jesus, i thought mine was bad at 50!


a mate of mine used to do ~65 each way - but that was from the east side of edinburgh to the west side of glasgow at rush hour (strait through the two worst rush hours in scotland)

[Edited on 4/8/2010 by mcerd1]

graememk - 4/8/10 at 08:46 PM

wimps for 7 years i drove from Boston to Hemel every day, thats 120miles each way.

as for bike rpm... havent a clue.

thunderace - 4/8/10 at 08:47 PM

she should get 60mpg+ at around 2500revs
what is se geting out the bike ,i work my bike out as 110 miles is £10 and thats me out playing

thunderace - 4/8/10 at 08:49 PM

quote:
Originally posted by graememk
wimps for 7 years i drove from Boston to Hemel every day, thats 120miles each way.

as for bike rpm... havent a clue.


why ?

graememk - 4/8/10 at 08:57 PM

quote:
Originally posted by thunderace
quote:
Originally posted by graememk
wimps for 7 years i drove from Boston to Hemel every day, thats 120miles each way.

as for bike rpm... havent a clue.


why ?


because thats where i used to work...

skodaman - 4/8/10 at 09:36 PM

As low as it will run comfortably at should be best. I thought you were supposed to keep the rev counter needle in the little red triangle at all times though.
I doubt you'll get good fuel consumption out of any four cylinder bike though, that's not exactly what they're made for.

rf900rush - 4/8/10 at 10:02 PM

I commuted on a '96 ZX6R and got 50+ mpg
Did not often go above 10,000rpm.
And 65mpg when I was running it in.
The only thing was they were short journeys and mostly under 50mph.

Simon - 4/8/10 at 10:52 PM

quote:
Originally posted by skodaman
I doubt you'll get good fuel consumption out of any four cylinder bike though, that's not exactly what they're made for.


I had to go on a work conference at Celtic Manor a while back and there was about 40 miles of roadworks on M4 resulting in a very long stretch of a 40 limit.

I reset the trip on the fuel computer and got 72mpg

from my 'busa

So it cost me 30 quid in fuel and 80 quid in tyre wear

ATB

Simon

franky - 5/8/10 at 07:45 AM

A v twin will never give great mpg but a little sv650 should do 45ish mpg on a commute. I've a 1200cc v twin that does 35 on my 45 mile commute to work.

smart51 - 5/8/10 at 07:58 AM

My R1 MNR did 30 MPG when thrashed and 35 - 40 when driven gently. How come a 600cc bike can't do loads more than that? It has 60% of the engine size, 40% of the weight and taller gears. Surely it should get 45 MPG with ease and well into the 50s if treated gently.

Mark Allanson - 5/8/10 at 08:41 AM

quote:
Originally posted by rf900rush
I commuted on a '96 ZX6R and got 50+ mpg
Did not often go above 10,000rpm.
And 65mpg when I was running it in.
The only thing was they were short journeys and mostly under 50mph.


Thats about the same as my daughters Fiat Punto driven the same way (excepting the 10,000 rpm bit!)

What exactly do bikes do with the fuel? Burn a third and spray the rest over other motorists?

By uncle had a Honda Benley 200cc 3bhp(ish) which did 200mpg - are there ANY economical bikes around these days?

Miks15 - 5/8/10 at 10:10 AM

i get 45MPG easy of of my TT600 on a 35 mile commute. And thats not going too slow. i reckon i could get over 50 no probs if i went steady