Bike fuel economy

[Christoffee]

Now, I've hardly conducted any research but it seemed to me that bike fuel economy is pretty low. So I thought is compare the mpg figure for a CBF1000 and a Honda Jazz.

According to MCN the CBF does 42mpg, and according to Honda a standard 1.2l Jazz does 53mpg.

I realise this is hardly a scientific study, but it does seem strange to me. Bigger engine, big dollop of car to lug about, air con to run and the car is getting better mpg. Why is this?
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Bike: CBF125

[ficedula]

CBF1000 engine is hardly tuned for efficiency, but you can bet the Jazz is. The CBF is actually generating more power than the 1.2L in the Jazz! - which shows you where their priorities were when they put the bike together.

Compare the Jazz to (say) a Ninja 250 - the Ninja will get better fuel economy and still be a helluva lot quicker.

Nobody's going to build a litre bike tuned for maximum efficiency, because why on earth would you be buying a litre bike if your concern was fuel efficiency? The Jazz, though...
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Bike history: YBR125 -> XJ600

[P.addy]

My R1 got over 50mpg, that thing would beat the Jazz in 2 gears.

Wouldn't take the mpg as truth though, when I had the work Jazz, the 1.2 suffered on the motorway and was revving high, averaging around 40mpg.

The R1 however, just over 50.

[TT_Man]

Agree with all above.
The bike engine is not designed for economy- its generally designed to produce the most power possible from that cc engine.

Also if you think about doing 80mph on a motorway in a car and a motorbike.
Car- probably cruising at about 5k rpm
Motorbike- probably about 8-9k rpm
The motorbike engine is doing a hell of a lot more revolutions than your mondeo, and on each of these revolutions its sucking in fuel to push those pistons round.

[doggone]

There are economical bikes which are still fun.
I have Honda CRF250L which has surprised me with 80-90mpg even with almost half the miles off-raod.
But it can't do much more than 70mph.

[P.addy]

[TT_Man]

[P.addy]

Golf 1.6 8V.

[TT_Man]

[Christoffee]

All very interesting, but I'm still none the wiser!

Now, I know it's a diesel but this Focus does 0-60 in 8.6 seconds, so pretty quick (obviously not R1 quick) and does 56mpg.

https://www.parkers.co.uk/cars/reviews/facts-and-figures/ford/focus/hatchback-2011/50253/

I dunno, it seems to me that you could have very good performance (but perhaps not blistering) and massively increase the mpg. And how often is your 1000cc bike flat out? Paddy's will be, but normal humans?
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Bike: CBF125

[Tungtvann]

A detuned, less revvy 1000cc bike that can do über miles?

[Christoffee]

[Rogerborg]

[Andy_Pagin]

My most economic car does 17mpg, all depends what you're comparing. To me 96bhp from a 600cc engine with Ferrari like performance and around 50mpg is quite reasonable.
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They're coming to take me away, ho-ho, hee-hee, ha-haaa, hey-hey,
the men in white coats are coming to take me away.
Yamaha Vity -> YBR125 -> FZS600 Fazer -> FZ1-S Fazer

[-Matt-]

High peformance takes the priority has always been my understanding of it. That being said, my 1L corsa does 40-50mpg on 'good' roads. My zx6 does 45 or so steadily, with town riding (even when unable to filter a lot this is) and spontaneous bursts of hoonage.

Quite impressive IMO.

Considering a car of similar performance would be getting 15-25 perhaps?

[David072]

My car, a 1.8 honda accord sport gets around 30MPG I reckon. I've had my Fazer nearly a month and reckon I get around 50MPG.

The car is also £280 a year to tax, the bike is £60ish (I think?), plus £10 or whateverthehell it is now to drive in the congestion charge zone along with the extortionate car parking prices (if you can find a space) in London.

I reckon I've done about 300 miles in the car at most since I did my CBT in march, and haven't driven it once since getting my big bike.

The bike costs me £20 petrol for the commute per week. If I got the train, I'd be paying roughly £70 per week I reckon.

I guess I'm lucky that riding a bike in London is cheaper than driving and getting public transport, but even if it wasn't I still would, the fun is priceless.

[Kickstart]

Hi

Big reason that bikes are so poor is due to dire aerodynamics, and the higher the speed the more important that becomes. Having a small frontal area can only salvage the cda so much when the cd is so bad.

Add to that bikes tend to be fairly high performance, and at lower speeds only a fraction of that ultimate performance is required. To reduce that performance the intake is throttled, which screws up the efficiency.

Comparing fuel consumption of a bike to a diesel car is a bit wrong though. One major reason diesels get better fuel consumption is that diesel fuel has a higher energy concentration, so you get more of a bang per volume of fuel.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[DrSnoosnoo]

1.8 Celica VVTi - 38 mpg on the last tank with many motorway miles
ZZ-R 600 - 47 mpg commuting in town - with motorway 60-65 mpg
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I'm Sam; Northern, Ginger, Lover
Did have: '95 ZZR600 '83 CG125 '97 ZZR1100 '15 Hypermotard 821 SP Do Have: '10 ZX10R

[garth]

My car has 58bhp, weighs 875kgs and does 60mpg.

My bike has near double the power, weighs a fifth of the car and does 32mpg.


Hmm.

[esullivan]

I'm in the odd position of having both the NC700 *and* a Jazz -- the former has theoretically half of the latter's engine. The Jazz gets mid 40s in almost 100% city driving, while the NC gets just shy of 70mpg in about 60% city riding. It's not apples to apples, though, since my wife's Jazz is a hybrid.

I don't think we'd want some of the fuel-economy innovations of cars on bikes, since it would negate most of the benefits. Driving the Jazz sucks, *especially* around the city. It's like a golf cart. It's aggressive about shutting the engine off when stopped, for example. Some scooters do this, but I don't think we'd want this on a motorbike.

The NC, despite what everyone says, feels quite nippy on normal roads, with the same torque as bikes with twice the horse power. I think it's a relatively good balance. They could probably eek a bit of a efficiency out of it, but there's a line between cars and bikes that we probably don't want to cross. On scooters, yeah maybe.
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Current: '14 VFR800X Test passed 31/10/12.
Previous: '12 NC700S, '11 CBF 125, '04 SH 125.

[ficedula]

If anything, I'm surprised the NC doesn't get better than high-60s on the MPG ... my XJ600 gets ~65mpg and it's a way older (and more powerful) bike.

Although I suppose you're doing more city riding than me if it's ~60% of the riding - do you know what the NC gets on the open road? Closer to 80mpg?
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Bike history: YBR125 -> XJ600

[esullivan]

[garth]

Bikes aren't built for economy. Most bikes that are economical I have no interest in riding.