Gas mileage

[Paul Kelley]

Hi everyone,I have A stock 79XS-11that I get 35 mpg with,Is there anything I can do to improve that number? Thanks Paul;

[CatatonicBug]

I'd say you're doin' pretty good there! I average 30-32mpg, but I'm not tuned up as good as I could be. I've heard of some that get up to 40 or so, but I'd be rather happy with what you're getting!

[Bigfoot]

For a 79 that doesn't sound too bad. There are some modifications that can be made such as swapping out the final drive for one off of a 750 or 850 xs. How you ride also seems to make a big difference in mileage. On mine it seems if I keep it under 70 I get in the high 30's - low 40's. Bump it up to 80 and I lose about 5mpg.

And welcome to the site.

[Ivan]

Hi everyone,I have A stock 79XS-11that I get 35 mpg with,Is there anything I can do to improve that number? Thanks Paul;

There sure is. Ride it faster and keep the throttle pinned as much as possible, then you'll get it back to the normal 25-28 it should be!

Seriously though, that is about right, some do better some to worse.

Welcome to the sight.

[Poprock]

850 FD, full bagger and fairing, running 1 oz per 5 gal. of gas, getting 46.4 mpg. I drive on the coast, 55 mpg speed limit, slower than that a lot, due to traffic (trucks, tourists, etc.) Speed kills -- mpg!
(BTW) the bike loves the acetone. It's cleaning the carbs for me as I drive. Idle gets smoother by the day, low end torque is picking way up, and I'm 3 mpg up over plain gas.

[Crazcnuk]

Derwat dropped his needles one notch (79SF) and went from low to mid 30's to high 30's low 40's.

His best, so far was 43mpg at 65-70mph.

I am just slightly lower, but i have played with my carbs a lot.

[Paul Kelley]

Thx.

Thank you for the info so far. I have been trying to find information since I found this bike. The former owner had it in his garage since 1988, I bought it in 08. The bike has A vetter fareing and I drive 100 miles daily. I was also wondering if A 4-into-1 header would help. This is A realy great site and thanks again. Paul

[TopCatGr58]

Hey Paul,

Stock pipes provide the best all around performance, good low rpm power, and midrange, and decent top end. The 4-1 pipes are usually tuned more for providing more power in the mid/upper rpm ranges, but sacrifice a little bit in the low rpm range. They don't necessarily provide any more mileage!

What rpm are you running those 100 miles at?? What MPH? The 4k range is the sweet spot for these engines. You are pushing a large windshield/fairing thru the wind, the faster you try to go, the more wind resistance you'll encounter.

Some folks have leaned their machines out a bit by raising the floats(upside down point of view), can give a slight loss of power in the upper rpm range, but if you don't run there, then not necessarily a loss if you gain a few more MPGs.

Hotter spark may help burn the fuel more efficiently, if you are running the old stock coils, an upgrade to the MIKESXS type "might" help. What type of tires are you running, and what pressures? Using touring type harder compounds can reduce road resistance.
But has already been said, 35 mpg is pretty good/normal.
T.C.

[xschop]

42!!!!!!!

Went thru an entire tank from the last 6-7 days of riding. I reset the digital speedo and got 211 miles out of 5 gallons with the new FD 3:1 ratio.
I did city and hiway miles mixed throughout. I am really liking this new gearing. It has 750FD characteristics on the Hiway and a very nice launch starting in 1st. Can't wait for the next long trek.

[dbeardslee]

Paul - I average 28-32 mpg in city driving with fairly aggressive throttle twisting. On the highway at a constant speed I get around 44. If you want to see what kind of mileage your capable of fill your gas tank and take a long all-highway ride at a constant speed. Gas up again immediately and check your mileage. Riding style seems to have more of an impact on mpg's than anything.

[Paul Kelley]

More info

Hi ya'll,I ride 50 miles on the freeway @4500rpm 68 to 73 with donlop202 tires @ 40psi. If I keep up with trafic i'm at 5200 rpm (to fast for me).I've been using 91 oct. and staying in the right lane and i'm easy on the throttle.Sounds like the 750 or 850FD is the ticket, I really want to keep the bike stock.I love the sound and feel of the bike.I was having carb trouble so I bought A set of Keihns, really didn't like them, and found A parts bike with A good set of '81 carbs on it, so went back to stock.
Once again THNX Paul,
My next question might be on the final drive swap after I do more research.

[cywelchjr]

Hi ya'll,I ride 50 miles on the freeway @4500rpm 68 to 73 with donlop202 tires @ 40psi. If I keep up with trafic i'm at 5200 rpm (to fast for me).I've been using 91 oct. and staying in the right lane and i'm easy on the throttle.Sounds like the 750 or 850FD is the ticket, I really want to keep the bike stock.I love the sound and feel of the bike.I was having carb trouble so I bought A set of Keihns, really didn't like them, and found A parts bike with A good set of '81 carbs on it, so went back to stock.
Once again THNX Paul,
My next question might be on the final drive swap after I do more research.

My personal experience with both my XS11 and my XS400 is that I get better gas milage with 87 octane than with 91 and I can't tell any difference in how it runs.

[TADracer]

I also use only 87 octane mainly because I think the refining process is much more accruate than it was in 1978-1981. Last time I checked milage accurately I got a shade over 41 MPG in mixed driving. IMHO, the keys to getting that kind of milage is to tune, tune, tune until you get it right then ride with the tach in the sweet spot as much as you can. Milage sucks if you are putting around at 35 in 5th. While these are no longer considered high RPM bikes, keep that tach needle ariound 3500-4000 and you should get pretty good milage.

[CatatonicBug]

Yeah - using anything more than Regular unleaded is just a waste in these engines. We don't have the hardware required to take advantage of the higher octane, so you're just throwing away your money on the more expensive fuel. However, if it makes you feel better to do that, it won't hurt anything.

[tarzan]

I got 38-42 with the special.I usaually drive about 5-10 miles over the limit with moderate hotrodding around.