'78 Cycles article on the XS1100 & mpg

[FSCGunslinger]

I've been reading over the old article in the '78 issue of Cycles magazine that Dragon Tamer sent me about the XS1100. In the stats section is says that this beast got 44.7 mpg!!! Can someone explain that to me since ours now-a-days only get around 32 or thereabouts? I'd surely like to know!

[stoked]

My best guess would be they didn't calculate it correctly. The lower speed limits back then could also be a factor. Going 55 mph does significantly reduce your drag from wind and lower your rpms quite a bit compared to 70 mph average. But at best I would think that would get you around 38 to 40 mpg.

[DiverRay]

I used to get 45 MPG ALL the time with my first XS1100. It was a '78, serial number 000254. Best MPG was 53, two up on a ride with about 15 bikes. worst was about 39, WOT almost the complete tank.
The fuel we have now is different, and DOES NOT pack the same BTU per gallon. That is the biggest single reason for the MPG difference. I was only able to get 38 MPG with my present bike, before the final drive switch. I now get about 42 MPG on my commute.

[Pat Kelly]

Could it also be that gasoline was different then? There are things added to gas now to make it "cleaner".
I know gas I buy from AM/PM costs less but my fuel mileage is less with that gas.

Just a thought.

[xswilly]

We had leaded gas back then, more lubrication
i think unleaded gas makes the engine run hotter
i also had mine back in 78 and did get 40 - 45
when i ran around the speed limit
but when you let it loose the mpg droped into the 30- 35 range

[FSCGunslinger]

Hh... interesting about the gas differences. So what should I realistically be looking to get for mpg out of my XJ11 that's in great running condition? I hear they are suppose to get better mileage than XS's. Is this true?

[boyat68]

If you apply physics to the question, and assume that the 10% ethanol blended has less than 75% of the power of standard gasoline coupled with the fact that the original figure was derived from labratory conditions, (Cycle running on a dynometer in a closed enviroment running leaded gasoline), then it is any wonder that you will get 30 miles to a gallon.

[stoked]

Wow, you learn something new every day. I had no idea gas had become that ineffecient. I wonder if that's why quater mile times seam a little quicker back then also.

[erithanis]

:BLINK: I get 40-45 right now. I haven't tuned the engine at all since I got it. Not sure why your poor beasts are dragging.

[egsols]

Mine was running good, mileage not great but after I synced the carbs the mileage went way way up!!

[stoked]

Originally posted by egsols
Mine was running good, mileage not great but after I synced the carbs the mileage went way way up!!

Hmm, interesting. This may be the thing that finally gets me to do that.

[Ken Talbot]

For the longest time, Tsunami, in full dress form, averaged around 30 mpg (US gallon), even with a fresh sync and colortune. But, the plugs were always black. I dropped the floats by 2mm in each bowl, and the plugs cleaned up, and the mileage came up to a consistent 40 mpg. As before, this depends on having a good colortune and sync job, and taking it easy on the right hand. 44.7 should not be impossible for a nekkid bike in good tune.

YMMV

[trbig]

While cruising to John and Wildkat's in Texas, at the speed limit of 70mph, I get 35-37mpg. At 80-85, I get a little better than 40mpg?? Explain that one! So guess how fast I usually ride?? lol.
Headwinds/tailwinds will change things up by several miles a gallon though. I've had a 10mpg difference sometimes between going somewhere and returning in a strong wind.


Tod

[mro]

Cruising 45/55 the G gets 40+ mpg.
Around town, 32/36 mpg
Specials getting 32 to 38 mpg

Have been contemplating the final drive mod for one of the specials.


mro

[Squatch]

so lets say i want to go on an insane trip across country, how would i get my ileae up on my special, i mean whats the difference between the special and the regular, i know about the 55 mph golden zone with most vehcle, but what if i want to go faster, can i tune my machine for better milage at 65-70?
an what am i looking at on mpg for my 79 special... any mods that aren't too serious (transmissions freak me out...) or am I just stuck with a sub 40 mpg bike...
also how hard is the final drive mod to do...
I'm trying to get the best gas mileage out of my baby for a long ride (roughly 4000 mi) and I want to save money...










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