Gas mileage

[rover]

mileage

I usually get 34-36, but last tank, I rode with the wife who is afraid of cycles, drove very carefully so as not to scare her, and got almost 42.

[Hmar]

81 special, no windshield or fairing or 2nd gear, get just a hair over 38 mpg on the highway, little less in the city. I suspect revving up to shift from 1-3 isn't helping me
I get anywhere fron 100-110 miles between fill ups.

[KA1J]

I'm really appreciating the answers coming in from this poll. I don't though know what is causing me to have lower mileage numbers. It's a XJ11 with the eliminator in place and I have a Jardine Spaghetti in line. Other than the Jardine, everything else is stock. My saddlebags rest nicely on the tops of the mufflers and if I use the stock exhaust the leather bags won't fit properly. The Jardine is so close to the specs of the original system that I can't imagine it is dropping my mileage to the low 30's even when I'm on the interstate holding at 65.

I'm going to install the original exhaust even though there's some dents on the top of the L muffler and see if that makes a mileage difference. I sure hope the PO didn't rejet when he was into it, I didn't write down the values & hopefully I can find some photos I took of the carbs when I rebuilt them & see what compares to stock values. (Never thought to check if the jets were changed).

May do that in the garage tomorrow during the storm...

[jetmechmarty]

You know, you really shouldn't raid the local airport or marina for fuel and oil for your motorcycle....

I'm not aware that marine fuel is leaded. I'm pretty sure it's not, but often (at least here) it lacks ethanol. Aviation fuel (100 low lead) is loaded with it, last I was aware.

[KA1J]

I live right on the coast & called several marinas around here and all of them have alcohol in the gas. I asked a friend who owns a marina in Rhode Island about it and their gas has alcohol. I gassed up at a Stop & Shop gas station last night and asked the truck driver if they add the alcohol before delivery or if it's added at the station during filling. He said they mix it at the terminal and if the alcohol runs out during filling, they have to note where that was in the gas portion and then the alcohol gets added from another supply to make up the 10%.

$%^

[jetmechmarty]

Fortunately for me, ethanol free fuel is available in my part of the world.

http://pure-gas.org

Some states are SOL.

[Toolmaker Tim]

Riding Double

I have been getting about 32 mpg with SWHBO on the back, which is a bunch better than the 26-28 mpg before I put the JBM diaphragms in. I need to go on a long ride 1 up to find out if there is a difference in milage without her. Of course it may have ben the 5 degrees advance I put in the timing that made the difference.

[3Phase]

I'm not aware that marine fuel is leaded. I'm pretty sure it's not, but often (at least here) it lacks ethanol. Aviation fuel (100 low lead) is loaded with it, last I was aware.

Some marinas still have leaded fuel available but some of them also have their fuel tanks sitting on/in/around/under the docks so your XS gets a couple of gills of marina water along with whatever else was in Bubba Gump's tank that day.

Bleh....

[XJOK2PLAY]

I don't though know what is causing me to have lower mileage numbers. It's a XJ11 with the eliminator in place and I have a Jardine Spaghetti in line.

My XJ got consistantly between 30-32 when I first got it a few years ago.

2 things I have done that resulted in consistant 38-40 mpg.... Dynajet kit, followed by a careful synch and achieving higher vac readings through adjustments... and the 850 FD swap.
(Higher Vac readings, I've found, are a lot more critical on an XJ than the XS due to the electronic timing control...)

For mine, I've also noticed weight doesn't seem to factor much... I've clocked 40 several times on highway trips, riding 2-up! (Approx. 350#'s...)

Now, riding into a strong headwind for many miles will definitely make a huge dent... sometimes as low as 32...

I've got a Vetter 4 with the tall windshield, hardbags, and trunk.

My bike also suffered from hard starting when hot, uncontrollable/inconsistant idle speeds, and bogged around 2000-3000 rpm...
After the DJ & synch... fixed all that. I had to play with the needle settings a couple of times before I got it right and saw the difference in MPG's, but torque & rideability was much improved right out of the chute after the DJ kit.

I've also noticed that keeping my speeds at or below 65 mph on the highway helps a lot, too!
The 11 gets pretty thirsty, the faster & harder ya ride it!

JAT... hope it helps.
Bob

[Redshirt]

79 special
stock exhaust, airbox, jets
rider weight: 290 lbs (all muscle....except for the 50 lbs of fat)
riding conditions: flat terrain.
warm climate.
sea level.
Libra with moons in Capricorn.
Vetter Fairing. No bags on. Cut down windshield (18 inches).

With moderate riding with mixed city and highway conditions, I get an average of 35 mpg. However, I have had heavy handed riding get me about 28 mpg.
On long highway hauls I get about 38 mpg.

My idiot light comes on at about 98 -101 miles. By my calculations leaves me with almost 1.5 gallons in the tank.

[Bonz]

When I've quoted gas mileage over the years on this forum, I speak of the commuting on my 80 SG that has a good part of Interstate where running 75 mph is the norm, and my mpg for that riding is pretty much 37-38 mpg. I have the FD swapped on my bike.

For the Colorado Rally this year, I put 1025 miles on the bike at speeds that stayed under 65 mph for the most part, and at least half those miles were in the mountains in the 45-55 mph range, going up then going down, going up, going down, etc in elevation. The bike returned 46 mpg for the trip average.

Did a nice 135 mile round trip Sunday ride two weekends ago with some other riders, speeds were in the 45-55 mph range. Averaged an even 50 mpg for that ride.

What I am realizing is that speed has a tremendous effect on the mpg my XS will get, even more so than any other bike I've owned.

Since speed limits were 55 mph around the nation back when the XS came out, is it fair to say that Yamaha designed the bike to run most efficiently at those "lower speeds" per se, regardless of FD swap or not? What I am getting at, is if you ride at 45-55 mph, then the FD swap really doesn't come into it's own because the XS doesn't really make a lot of go-go until 3,000 rpm anyway. Thus at the lower speeds, I find myself in 4th gear with the swapped FD vs. running 5th gear with the stock FD (to keep the bike around 3,000 rpm in either case).

The more I ride with the FD swap on my bike, the more I realize that the nature of the engine in terms of having get up and go, is to keep it above 3,000 rpm or it can't pull the skin off a banana.

I like my FD swap, and because I run higher speeds on the interstate it makes sense in terms of overall lower rpm and associated wear and tear, along with a couple mpg increase at those speeds.

BUT I am coming around to realize the FD swap does make the most sense if you want that "overdrive" gear for the open road. Otherwise, it would seem to be a non-benefit.

[strom]

1979 XS 1.1 (european standard), stock headers, without an H pipe, Louis universal long mufflers (www.louis.de), free flowing air filter (just the steel mesh):
- Cruising like a grandpa, in a group and watching the scenery: 47 mpg
- Cruising: 38 mpg
- Touring pace (quite fast, scaring some crotch rockets): 31 mpg

1978 XS 1100 (78E in the US), home-made headers with same exhaust as above, same air filter:
- Slow, fast, stupid, no matter how you ride, with or without full Vetter setup: 26 mpg

This bike really REALLY needs new carbs. Cannot be set up due to damage to the carb bodies while extracting broken idle jet needles.

[Flyman32]

???

Color me stupid. What's FD Swap?

[XS1100 Newbie]

The final drive, or rear differential.

[jetmechmarty]

Do a search. The FD subject has been covered extensively.