28 mpg

[thuffman]

Hi everyone, I'd like your input on appropriate mpg for my bike. It's an '81 Midnight Special, around 22,000 miles. Recently, I've paid to have all four carb insulators replaced, all four carb dipraghms as well (3 of 4 had leaks). Got the "puddle of gas" dealt with (Properly routed gas lines-also lowered floats to 1/4" below bowl). Man, it's got power enough for my fat a** now! Problem is, I can't get better than 28mpg even if I ride sanely.
Anyone else in this range or has a clue for me? Thanks alot.
Tim.

[Czekus21]

I was getting about 33 mpg avg. before I adjusted the valves, floats, and resunk the carbs on my 79sf. Now I'm in the same range as yours but more power and alot smoother acceleration.
There were a few threads posted about this issue, I think about a month or so ago. I think the threads were titled " Fuel Consumshun. Boy, It looks like I went to the billy bob school of spelling. That's what I get for not Gadgiating High School.

[thuffman]

Thanks, I'll look for those posts.
Tim.

[Bubba1954]

After carb sync, valve adjustment, new plugs, timming set correctly and a timming chain adjustment, I'm getting 35MPG consistantly with my full dress 1979 XS1100 STD.

That's while averaging 70 MPH too! I'm not very diaponted since that's what my 1988 1500 Goldwing would do on a good day at the same speeds!

I'm sure it would likely get 40 MPG if I wanted to just ride it at 55 MPH as the Hwy speed limit was back when it was introduced.

[wildbill]

My bike a 78E when I first got it got around 40 mpg.Then the mileage dropped into the 20s.I have since done quite a bit of work to it to restore it back to where it was.The first XS I owned averaged 45mpg.There is a lot of little things that can cause a drop in gas mileage.These can be dragging brakes,bad plugwires,carbs not to mention the wires that hookup to the coils.I know there are some things I have left out but the above gives you a idea.

[stal871]

I don't feel so bad now. My 81 special impresses me everytime I drive it, with its tremendous power and smoothe accelleration all the way thru the tachometer, but I've never been able to pull more than 25-28 mpg no matter how soft on the throttle I am. It also has just over 23,000 miles, about the same as yours. I'm not gonna mess with a good thing just to try and save a couple bucks each summer.

[thuffman]

Took a 120 round trip yesterday, finally got over 30mpg. A couple days ago, I checked my plugs, found one quite fouled. Testing revealed one resistor cap not resisting (bad). I may replace the other three just based on age. Every thing's gotta fail some time.
Sure was good to take the bike over some passes, kinda burns everything else out of your head 'cept the kamikaze insects aimed at your teeth. (You gotta be smilin' !)

[tfm3]

35 mpg consistently on '81 11H full dress. 90 mph max on mostly open roads at average 6000' el. I'll check again when I spend all day at 9-12000' el. next week. I hear premium [91 oct.] will be close to 3 bucks/gal in the mountains by the end of the month. Seriously looking at that rear aux tank idea.

[noeleo]

Re: 28 mpg

Originally posted by thuffman
Hi everyone, I'd like your input on appropriate mpg for my bike. It's an '81 Midnight Special, around 22,000 miles. Recently, I've paid to have all four carb insulators replaced, all four carb dipraghms as well (3 of 4 had leaks). Got the "puddle of gas" dealt with (Properly routed gas lines-also lowered floats to 1/4" below bowl). Man, it's got power enough for my fat a** now! Problem is, I can't get better than 28mpg even if I ride sanely.
Anyone else in this range or has a clue for me? Thanks alot.
Tim.

thuffman,

I ride a 1980 Midnight Special with under 300 miles (see my post about diagnostic nightmare). I rode last Saturday 200 of these 300 miles with it running poor (just couldn't stand it), and got 35-36 mpg. Of course, the speeds were limited to under 70 MPH. I'm not a large person (195 lbs.), and I realize that could make a difference, but I felt really good about my mileage. I'm hoping that after I fix the running problem, it will get better. It just has to. Anyway, just my .02!!!

[rover]

My F with over 63,000 gets from 37-42. My SF, it had 6,000 when I got it, now has over 97,000 always ran about 30-32. I just got the F last winter. Both are full dress. I run about 10 MPH over the speed limits, most of the time.

[Materi]

"The Breeze" seems to do about 26-28, but runs like a dream. Starts great, great acceleration.... hauls acid etc. Like Stal87, I'm not going to start jacking around with it to save a couple of bucks. BTW, I weigh about 185 dressed out, and my brakes in fact probably do drag a little, but that is slated for rebuild when the snow is flying.

Keith

[Bubba1954]

Originally posted by tfm3
35 mpg consistently on '81 11H full dress. 90 mph max on mostly open roads at average 6000' el. I'll check again when I spend all day at 9-12000' el. next week. I hear premium [91 oct.] will be close to 3 bucks/gal in the mountains by the end of the month. Seriously looking at that rear aux tank idea.

Save your money and buy regular gas when ridding in higher altitudes. Engines that require higher octain will run fine on lower octain at higher altitudes. My auto tech instructor tought me this back in the 70's when I drove a high performance big-block street racer while going to school in Denver. I tryed his theory out and he was right. never used premium again. I visit Colorado by bike from time to time and always switch back to regular when mountain touring.

[Upright]

My '79 F with a Windjammer SS gets a consistent 35 mpg in town.

[tfm3]

You're absolutely correct,Bubba1954. Ran a little lean in the wallet last week so I filled the tank with what was left of my lawnmower fill can, cheapest fuel around. No performance difference whatsoever. Ten years ago my '79sf would only run on premium,when it ran at all. That was at sea level.Drop us a post next time you're in the neighborhood!

[Geezer]

Originally posted by thuffman
Took a 120 round trip yesterday, finally got over 30mpg. A couple days ago, I checked my plugs, found one quite fouled. Testing revealed one resistor cap not resisting (bad). I may replace the other three just based on age. Every thing's gotta fail some time.
Sure was good to take the bike over some passes, kinda burns everything else out of your head 'cept the kamikaze insects aimed at your teeth. (You gotta be smilin' !)

Toss the resister caps and buy a full set of non resister-caps. You'll be better off in the long run.

Geezer