4 banger vs twins

[user removed]

Originally Posted by gil

Someone in here was riding a BMW 650cc bike named Teresa, he was getting impressive numbers. As far as I understand a single big cylinder is the most efficient. A automotive article from Car & Driver emphasized that 500cc cylinders, with long stroke, where becoming standard size for engines of the big car manufacturers. Weather it be a 4 cylinder or eight, 500cc per cylinder was determined to be the most efficient.

Why 0.5-Liter Cylinders Will Soon Dominate Automotive-Engine Design

gil

Details: Teresa - 2004 BMW F650CS Fuel Economy - EcoModder.com

regards
mech

[cRiPpLe_rOoStEr]

Originally Posted by sendler

The more pistons, the more surface area in the combustion chamber for any given displacement, the more wasted heat. The longer the stroke/ bore ratio, the more leverage and the less wasted heat. A fuel injected single is the most efficient.

BINGO!!!

Anyway, a few days ago I was talking to a friend about the possibility of fitting a stationary single-cylinder into some old beater just to perform some tests.

[Grant-53]

Any chance of finding a small diesel too?

[cRiPpLe_rOoStEr]

Originally Posted by Grant-53

Any chance of finding a small diesel too?

Guy Rides Kubota Diesel Powered Chariot Down The Track
Is this one small enought for you? Similar engines have been fitted into old Jeeps and compact trucks in my country.

BTW if a commercial driver license wasn't required to drive a tractor on the streets back here I'd be very tempted to build something like this one...

[pwillikers]

There is a really good article by Kevin Cameron, Motorhead Genius, on the subject. Google "Honda NC700X: Fuel-Efficiency Game-Changer"

[sendler]

Honda NC700X: Fuel-Efficiency Game-Changer: Shifting paradigms manually or automatically.

[Ophbalance]

Sadly, I only have experience with one bike. I bought a "old" bike two weeks back, '87 Intruder VS700. It's a VTwin that's 700CC but runs closer to a 750. I've only got two tanks in it, and I've not been at ALL gentle with it, but the average right now is about 48 MPG. Cruising on the secondary roads between 55-60 MPH and hitting short stints up to... well, fast . I'll be making longer trips starting in June with it but I expect those to be about 50 MPG average tanks (100 miles round trip into work). I'm pretty happy with that result, really.

[saturndude]

I recommend the SV650, theyre abundant, reliable, fun and effecient.
I have a 2000 sv650. I do drive for effeciency, however, 100% of my riding is through the worst LA traffic.
stock, I would top out about 50mpg
I changed the gearing and now get about 55mpg

I picked up a cheap 2000 ninja 250 thinking it would get even better mpg, but the best I got was 65mpg and usually more like 55mpg. Its a great bike but compared to the SV.... its more of a moped that can go 100mph.

I was looking at the same situation as you, older honda 500s or something like that, but my buddy who gets wined and dined all over the world to test ride and review sports cars and motorcycles told me "get an sv650, you'll never need another bike"

It's faster than any normal ferari or porsche or whatever, but gets better mpg than a prius. (this could very well apply to the other bikes you looking at too of course)

I picked up the best deal I could find a week later $1300 for a salvage title with 30k miles. well I'm almost at 50k miles a year later.

[Respectful Revolution]

Besides the fact of having read and heard repeatedly that twins are more efficient than 4 cylinder bikes, I can say from my own experience that Harley twins are the most efficient ones in their category (and I've been riding my whole life many different types of twins). I'm currently riding a Harley Sportster 883C modified for long distance and so long as I am on the road, riding to save gas (60 top speed, slow start, no gas to red lights...), I get anywhere between 56 and 62 mpg depending on conditions. I get 2/3 as much efficiency in town with stop and go traffic. EFI likes long haul rides to give maximum efficiency. If I was riding primarily in town, I think an older carburated Sportster would perform better than the injected one. Anyway, yes, I am NOT a Harley fanatic but I sure believe in the efficiency of my Sportster, again, properly handled.

[jkv357]

I'll toss in my 2 cents on the SV -

I have 2 of them, both naked versions, a 2006 I bought new and a project 2000 that is getting close to being ready to ride.

The '06 is F.I., the '00 is not. I geared the '06 up 1T on the countershaft sprocket mostly to smooth-out the highway cruise - which it did. I regularly cruise around 75 mph, and running ethanol-free 87 it will get 55 MPG on the hwy. Best it has done is 62 MPG with moderate backroad riding, but most of the time I'm revving it the 7000 to 8000 range with brief runs to redline. Around town it will do over 50 MPG with normal riding - shifting about 5000-6000 for the most part, but not being overly gentle.

The later models have dual plugs, and do even better on gas (power is the same).

Overall, the SV is hard to beat as a general-purpose street bike (I've had over a dozen street bikes since the early 80s). Plenty of torque, good range, decent comfort, excellent durability, good handling, and excellent MPG for a 650.