MPG and modifications poll

[Axel]

hmm

Golden ?

[Montreux_Blue]

I used to get about 42 mpg if I cruised 75 mph all day long. Mine also kinda had a hiccup under 2,000 rpm and I would notice a pop from decell about once every couple thousand miles or so. Now I have it colortuned and dynojet and get about 35 - 37 mpg cruising about 80 mph with no hiccup under 2,000 anymore. You must be running a little lean on your pilot circuit, a colortune will fix that.

[dbeardslee]

I can't substantiate this, but they say it makes a difference when you fuel up too. Evidently gas expands, so a gallon during the heat of the day isn't going to be as much as it would be at night. I can't see that making a huge difference, but you never know. I'd watch what it does over several tanks - probably give you a better idea of what it's getting. I check mine every time I gas up, and I always try to fill the tank to the same point. It seems like the less I move the throttle, the better the mileage. I usually run it around 75-80 on the highway and if I just maintain that speed it's pretty sippy with the gas. Those double down shifts are kind of like flushing a toilet though .

[STEPPENWOLF]

Well MR. Dbeardslee..if ya followed behind me I bet you would get 5 more miles per gallon

[dbeardslee]

I do tend to get my best mileage there.

[jmnjrpa]

cruising at 60/70 in 5th

Drop it to third and make like a rocket, all they see is a flash!
I don't see the point in having to convert kilometers to miles so I will stick with my 160 MPH speedo, but thanks anyway. Actually drove 40 miles on a fresh tank before stopping for topoff and could only get .8/.9 Gallons in so I made a point to check for the rest of the trip. Just put another 52 on her and almost did not get a gallon in at highway speed (75/80) on a straight run.
Mine pops on decel also. If color tune reduces the gas miliage, you can keep it. I know it will come up in three gears so I am happy with it. to the bank.

[MaximPhil]

I can't substantiate this, but they say it makes a difference when you fuel up too. Evidently gas expands, so a gallon during the heat of the day isn't going to be as much as it would be at night. I can't see that making a huge difference, but you never know. I'd watch what it does over several tanks - probably give you a better idea of what it's getting. I check mine every time I gas up, and I always try to fill the tank to the same point. It seems like the less I move the throttle, the better the mileage. I usually run it around 75-80 on the highway and if I just maintain that speed it's pretty sippy with the gas. Those double down shifts are kind of like flushing a toilet though .

Hi dbeardslee,
It is the temp of the fuel not the air temp. Use the pump in the shade and you should be OK as the fuel is stored underground.
Maxim Phil

[jmnjrpa]

Sorry,

Old wives tale. Gas expands, but not liquid in any appreciable amount with one exception (mercury). Leastwise that's the official side of the story. If it did you would have a burst tank or gas spurting out of the vent hole in the hot sun right after fillup!

[papanovember]

AvGas

I work at an airport and use my (modified) 79 XS11F for my daily commuter. I usually run a mix of unleaded and 100LL Avgas. I can get the 100LL for free, so I really never checked the milelage so much. I also have an aux 4 gallon tank on the back for touring. I fill the aux tank with 100LL and open one petcock on my main tank so they mix. I got rid of the vacuum petcocks.
On long trips(highway), I was getting around 32mpg, but I have aftermarket carbs....Anyway, these bikes were meant to run on leaded gas. I will check my mileage on the 100LL and get back...I'm in the middle of the gear fix..

[restorganize]

Stock 79 F

I just had to replace my old motor with 106k miles on it, 100k of which I rode, with a used motor that had been sitting on a shelf for eight years, of which no body knew the mileage. With the old motor I was getting about 30 mpg riding around Los Angeles, and with the new motor I am getting about the same. The new motor sounds tight and runs like a raped ape, but I am confused as to why my gas mileage didn't go up any. For reference, this is my commuter bike in LA, when I travel there for work. It doesn't have a fairing, does have hard bags, and I am 6'5" 250lbs. Any suggestions on how to improve the mileage would be appreciated.

Judson

[Winterhawk]

Got 37mpg even tonight using Johns setup for Jardine spaghetti pipes 4 into 2's. It runs so good now I have to ride it everyday now. Only had it about 6 years and I never felt this way on it before. Strange.

[dbeardslee]

restorg - This tech tip has some pretty good ideas for improving mpg's. 30's about what I get running around in city traffic, and applying the throttle pretty liberally. If I get it out on the highway and cruise at a constant 75 mph (750 FD = about 4500 rpms @ 75 IIRC) it gets around 42-44. Riding style makes a huge impact on mpg's. Have you tried checking it just on the highway?

[XS1100 Newbie]

I get 38-40 most all the time, unless i get on the freeway. Running at 70-75 MPH it tends to drop to 35. (strange) I did have a AH HA moment the other day. We took a newbie on his Sportster for a ride up to Mt St Helens. Lots of corners, and climbing the mountain, then freeway back. I got 50 MPG. WTF? Part of it i am sure is because we were going so slow in the corners, and the bad roads with the newbie. This guy has had the Hardley about 6 months with little riding, and dropped it twice allready. I think he needed a scooter.

[hamjam]

I modified mine to this and get 47 MPG
Displacement:1552.00 ccm (94.70 cubic inches)Engine type:V2, four-strokeCompression:9.0:1Bore x stroke:102.0 x 95.0 mm (4.0 x 3.7 inches)Valves per cylinder:4Fuel system:InjectionFuel control:OHVIgnition:TCBI dual plug with digital advanceCooling system:LiquidGearbox:5-speedTransmission type,
final drive:Shaft drive (cardan)Chassis, suspension, brakes and wheelsFrame type:High-tensile steel, double cradleRake (fork angle):32.0°Front suspension:41mm hydraulic fork / 5.9 in.Rear suspensionual air-assisted shocks with four-way rebound damping / 3.9 in.Front tyre dimensions:150/80-x16 Rear tyre dimensions:170/70-x16 Front brakesouble discRear brakes:Single discPhysical measures and capacitiesDry weight:350.2 kg (772.0 pounds)Seat height:719 mm (28.3 inches) If adjustable, lowest setting.Overall height:1,506 mm (59.3 inches)Overall length:2,515 mm (99.0 inches)Overall width:1,039 mm (40.9 inches)Wheelbase:1,689 mm (66.5 inches)Fuel capacity:20.06 litres (5.30 gallons)

[ManitoulinLad]

44 mpg

The Tinman905 put a set of his carbs on my bike (1179 kit) and sync it. I now get 44 MPG going to work & back on the hwy. My bike hits reserve at 190 kms went to 210kms & still only put in 13.5 litres. Had a litre & a half still in the tank. No need for the big tank now. Things work out when all is correct - getting there & having the know how is the problem. - Dan