Most economical fast bike?

[Stu]

Originally Posted by kwak zzr

i was always made to believe it was 62mph in top gear for max fuel economy, reading car books and the like.

It used to be mpg at 56 mph until they changed to Extra Urban (?) But the reason for chossing those weird mph's is just that they are round number KPH (100 and 90).

I have no intention of having a fast bike & riding it slowly for economy, what I wanted to know was which is the most economical bike riding at + or - 100mph?

Still confused about which gear is the most economical at 30 or 40. If I wasn't accelerating faster, I would say close to top otherwise I would have to open the throttle to overcome engine breaking in 2nd or 3rd.

Also confused by Carbs v FI. I was reading a car mag (honest i haven't bought one since 2005!) that said without FI we'd all be driving cars less than 120 bhp with best economy of 20 mpg. So how come Sid Squid's ZX-6 for example is so good?

Stu, on the whole, big twins seem thirsty, I reckon about 30mpg (well that's my experience of SV's in France and my Falco 90-100 miles between refills).

My Fire'Blade has a 17 litre tank, so bearing in mind that there is always some juice in it when I refill, let's say that it does around 140 miles between refills. (16 litres = 3.5 Imp Gallons) 140/3.5 = 40 MPG, so even that's not great.

Maybe I should ride it a bit slower

My point is that any big bike is not going to be super economical. Maybe you should put economy further down your list of priorities and concentrate on other assets that a new bike will have.

* I think a VFR has a tank range of around 250 miles and a 22 litre (4.8 Gallon) tank, that's about 50MPG...

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Originally Posted by Marshall

Jeasus i dont know how you do that, i barely get 120 miles out of my 955i before i have to refuel.

Because mine's the 2004 model with the much bigger fuel tank. Yours being a 99 model has the cover over the thermostat housing taking up a huge amount of space.

[fizzwheel]

Originally Posted by Stu

So how come Sid Squid's ZX-6 for example is so good?

Having watched sid and how he rides on last years AR, I'd wager because he is smooth and flowing, he plans his lines well and his forward observation is good, that way he can make gentle small inputs with the throttle and brakes, which makes him not load or work the engine hard which gives the whole thing an easier time. I'm wandering if he feathers the throttle slightly instead of hooning down the road with the throttle pinned to the stop all the time.

Or perhaps he just rides at a more economical speed....

I know you wont do it, but try it for a week, try riding everywhere at 10mph slower than you do now, it will make a difference.

[embee]

Originally Posted by Stu

....It used to be mpg at 56 mph until they changed to Extra Urban (?) But the reason for chossing those weird mph's is just that they are round number KPH (100 and 90)......

Yes, the required figures from manufacturers used to be a "city" cycle, 56mph (90kph) and 75mph (120kph) due to a European based test. This has been superceded by an "urban" and "extra-urban" (i.e. out of town or highway).
The old system used to be used to give a "combined" fuel economy by weighting the values 40%/50%/10%. If I remember correctly (it's a while since I was involved it this) the current system is weighted 45%/55%, may be wrong on that.

Also what folks have said about economy and efficiency is right. Don't confuse the two.

In petrol cars, the best economy is usually around 2000rpm in top gear. It's not a hard and fast rule, but it comes from the mix of road load vs speed (power proportional to speed cubed approximately), engine frictional losses, and thermal efficiency. Below 2000rpm the thermal efficiency of typical gasoline engines drops off, very much so below about 1500rpm, mainly due to heat loss during the compression/expansion cycles.

For a car, make sure the tyres are pumped up, don't have the boot full of tools/sandbags/paving slabs/washing machines etc, keep the windows closed if possible, don't use the aircon (a killer for economy), accelerate as gently as possible, use high gears as long as the engine isn't labouring below about 1750rpm, and cut the brake pipes.

(Legal - the last comment was a joke, do not cut the brake pipes! )

Bikes are a slightly different kettle of fish, high power to weight ratios (or the effects of the design giving it) tend to distort the issue a bit. The basic principles are the same though, smooth riding, easy acceleration, using mid-revs through gears, avoiding braking if possible etc.

Best economy from a bike will probably be if the speeds you're using are something of the order of half its max speed. Or put it the other way round, if you do mixed traffic riding at typically 40-60mph commuting for example, then a bike with top speed of about 100mph is what you're after. A 250cc might be the ideal kiddy for traffic commuting if you ride it specifically with economy in mind, but they tend to get thrashed so end up with no better economy than a 500.

I find it odd that there are no frugal frugal big bikes, for people who don't want a little scooter, but don't want 100bhp+ either. I mean, there are 1litre cars that have 70ish bhp, and despite weighing the best part of 1000kg, they're return mid sixties mpg average. Surely a similarly lazy 1000cc engine in a 200kg motorcycle would beat that easily.

Purely zone 1 and 2 in London traffic - 36mpg
20 Miles on moderately busy A13 into Central London and another 15 in London traffic - 44mpg
Long runs at 70-80mph with regular squirts to 100mph 51mpg

I too would like bikes to be more economical as I do a fair bit of commuting.

[Stu]

Originally Posted by sinbad

I find it odd that there are no frugal frugal big bikes, for people who don't want a little scooter, but don't want 100bhp+ either. I mean, there are 1litre cars that have 70ish bhp, and despite weighing the best part of 1000kg, they're return mid sixties mpg average. Surely a similarly lazy 1000cc engine in a 200kg motorcycle would beat that easily.

Honda Deauville is quoted at 55mpg http://www.motorcyclenews.com/MCN/bi...nt/?&R=EPI-342
But this thread was about 140mph+ bikes

Originally Posted by Jelster

Stu, on the whole, big twins seem thirsty, I reckon about 30mpg (well that's my experience of SV's in France and my Falco 90-100 miles between refills).

Just used this to work out the mpg on my Ducati M900......26.2

To be perfectly honest, I don't want to know what mpg I'm getting as long as I'm having fun.