latest mpg

[TopCatGr58]

Originally posted by nubee
Kinnda dumb question I know but here goes: How do you get an accurate MPG reading? If I fill my 80SG to the top, shake it well , that and the fuel expansion will insure I have a lap full of gas. I have a new cap that seems to fit well.

Hey Nubee,

It's best to use several tankfuls and then you get a larger sample of fuel to average. Just keep a notepad or piece of paper in your wallet and write down the gallons and mileage at every fill up. Then after several fillups, do the calculations. It will probably be a more realistic value as well since it will probably be over a wide variety of driving situations, highway, intown, WOT bursts, etc.!!

My little big bore, loaded saddlebags/trunk, extra suitcase, handlebar windscreen, mostly flat terrain, superslab to and from XS East, but I had a 30+ mph head/cross wind both up there and back , got about 32mpg on my special.
T.C.

[Del Tysdal]

MPG

I seldom ride this bike in town, 1978 XS1100. My wife does not like the ride on the 96 Sportster or the 2007 Shadow Spirit as much as she likes the smoothness of the XS. We use the XS for out of town trips just about all of the time. We have an old Susuki GS850 also in another city that we use when there. She likes it as it is so smooth.

[olebiker]

Any motorcycle I have ever had that came with a users manual always suggested that you never fill up the fuel into the filler pipe in the tank. I always bring the level just up to the bottom of the lip. Never ever had one overflow even if I fill it and park it in the sun.

[AustinPhoenix]

hmmm

Last two tankfuls I avg 29 and 31mpg. I got 31 on the high octane and 29 on the medium. I'm trying the low octane in my current tank.

No WOT, but I do have a 26 mile commute to work. Mostly highway with about 1/4 of the trip being stop and go traffic.

I would LOVE to find out any specs, settings, tips for getting closer to 40. I have a 750 fd on its way. I hope this helps!?

[Crazcnuk]

Did just over 1000kms on the weekend and averaged 26-27mpg.

Just slightly worse than a decent p/u truck.

This week I jumped up 2 jet sizes (110 to 115), and it helped a little with my high end throttle but will have to go somewhere to see if it changes the mpg.

[DJinNH]

Originally posted by Crazcnuk
Did just over 1000kms on the weekend and averaged 26-27mpg.

1000 kms....holy crap! I'd have to put my butt in traction after all those miles in one weekend. That or keep some ice packs in my chair for a few days.

Don

[olebiker]

That is 300 miles a day for 2 days.

[thewiz]

80G

with VM33 smooth bore carbs, a SuperTrapp 4/1 and K&N insert .... a solid 36 mpg on a 150 mile round trip to Planedick's cave. Astonishing, if ya' ask me ....

[81xsproject]

What I am seeing on mine with the AEM, is that from 3-6.5k rpm, my bike is very rich. I went back to stock pilots and am only running a 117.5 for mains. At WOT, 7k and above, the mixture leans back out to 12.5:1 - 13:1. So, the main is good. My personal theory is that the near 30 year old slide/diaphragm springs are a little sloppy/soft and allowing the needles to be higher than they should in the cruising rpm range. I haven't tested this theory yet, but I think it is the cause for my low 30's mpg.

[Crazcnuk]

"That is 300 miles a day for 2 days."

It was ~500kms each way. Out Friday, back on Sunday.

My speedo cable packed it in 106kms out of town, so I had to fill up everywhere Derwat filled his Special and use his trip meter to keep track!

I have 4 reciepts (where I had the kms accurate) and they were 26.3mpg, 27.5mpg, 25.2mpg and 30.3mpg.

This is US gallons, BTW.


__________________

[olebiker]

Not very good! Specially with gas were it is.

[DenyP]

I am almost afraid to clean my carbs and tune up the Timemachine. I get 39 - 43 mpg. I ride 50 miles each way to work (100 miles each day) I would hate this to drop to 25-30. At present the old beast will not idle with out the choke. Stutters above 6500rpm. I am waiting for the morgan carbtune to arrive that I ordered from California Sport Touring b/4 pulling the carbs and putting in new kits.

Deny

[xschop]

750fd mpg's

IMO, the ideal situation is to have the 750/850 FD MOD with 4-2 exhausts and properly tuned carbs you should be getting 40 mpg's at 70 mph. My naked bike got an average of 42 here in Oklahoma with it's lower elevation. The higer you are at sea level, the crappier mileage you will see....Chop

[Crazcnuk]

I have the 4-2 exhaust, but haven't put my 750 FD on, yet.

I went on a 300 mile round trip today, after going up two jet sizes (110 to 115).

Mileage averaged 28.7mpg(US). 120miles of this trip is at 40-60mph. The rest at 70.

[planedick]

Actually

You won't see much difference in mileage after the 750 mod. It takes the same amount of energy to accomplish a given task. Think about it. Lower gears mean many more bangs per minute, but less fuel per bang and higher gears mean less bangs per minute, but more fuel per bang. Physics contains lots of rules that can't be broken.