Thread: Mpg
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Old 21-04-2022, 08:47 PM   #9
spuggy
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Join Date: Apr 2016
Location: Farnborough
Bike: M900sie
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Quote:
Originally Posted by Darren69 View Post
My '02 S4 916 was running around 36mpg when I ran the numbers, I thought it was thirsty but I thiink that's normal actually. I think a good Dynojet map will make it richer low down so if you potter about at low revs you'll probably burn more fuel. V twins are not really economical compared to other big bikes, they can't be and an 1100 is going to be thirstier than a 916?

Is anybody getting more than mid 30's from an old school big twin?
My 1960's 883 ironhead Sportster with a magneto regularly got almost 50 MPG, when I was young and dumb and traffic was lighter. In fact, I went to switch it to reserve one night when it coughed/spluttered through some bends - only to realize it was already on reserve... Managed to keep it running 8-9 miles to the nearest 24 hour station by sloshing fuel from side-to-side - and it died the instant the front wheel hit the on-ramp and I rolled across the forecourt with only the tyres making any noise... It had 97 or 98 miles since the previous fillup....

With a 2 gallon XLCH tank and about a pint or so in reserve, you did tend to keep an eye on the odo. And this despite the crudest "carburetor" I've ever seen - a old "tomato-tin" Tillotson.

I agree though; when I broke 100 miles before the "low fuel warning" light on my '01 S4, I knew it was running so much better than it had previously (because I had been seeing 75-85 miles)...

In comparison, the 2001 900 Dark (also with a DP ECU, open airbox/DP high level etc) would regularly go 115-120 miles before the light came on.

I know the S4 tank is more hollowed out underneath (to accommodate the cam boxes) - but seemed to me that a 4 valve/DOHC/COP should be more efficient anyway - plus this seemed like a larger difference than you'd expect - it's not like the tank didn't accept respectable quantities of fuel...
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