High speed, HIGH fuel consumption

[Hyde]

Hey guys had some questions about high speed fuel mileage, because mine is horrendous.

Just finished my first 1k in a day (saddlesore) ride last night, it was my first big ride of the year and I'm getting much worse mileage than last year.

Bike background: 1999 Tourer, batwing fairing and big GL1200 bags, I know it's as aerodynamic as a brick. Austone taxi tire, Pingel petcock, Dan-marc fuel shutoff, ECT mod. The bike has 19,200 miles now, I got it last fall with 12,000.

The things I did this winter: Added the GL1200 bags instead of the small eBay bags that were on it, 18" glasspacks with 4" stacks, and an R&M belly tank. Also changed to an Avon Cobra front from last year's Metzler but I don't think that could do it.

My first leg of the trip I got a bit over 26mpg, which I find acceptable the way I ride and was close enough to last year's 27-28mpg average. After that things went down hill, I ran out of fuel at around 150 miles (with 8 gallons on board!) And that set the pace for about 20mpg or less for the rest of the trip. We rode at 80-85mph most of the time, sometimes slightly more. Before you say "slow down!" That's not really an option. The guys I ride with are on an ST1100 and a BMW k1200r and the speed limits on most of our stomping grounds is 80mph. I know I'm probably on the wrong bike for this group but I usually enjoy pushing the Valk to keep up and until this fuel mileage debacle I could push it hard enough to do so.

Anybody see anything I changed that could cause such a drastic difference or might I have a problem? Or maybe that's just the milage she gets at those speeds but not according to last years riding

[Led]

Not much you can do about that!!!

The faster you wish to go, the more fuel you will use.  And  it does not equate to double the speed, half the mileage either......

You start getting up to 85 MPH......you may use over THREE times the fuel, than just cruising along at 45 MPH.......

The faster you go, the more energy it takes.......just the law of physic's!

One would NOT think that the mods you made would make that much of a difference, but apparently so?     ???

[Bone]

The girls get thirsty at 85 mph. My 98 Tourer used it's tank in approximately 110 miles. Mine had a stock windshield. I will have to find my old post to be accurate with the numbers.
Going through New Mexico around 85 mph mine stumbled at about 85 or 90 miles on the full tank no way was it wanting to go on reserve. I switched it and she had the fuel she needed. I was in shock I guess not thinking I had a gallon left soon she stumbled, out of gas.  The thermometer on my bike was at 101 degrees.
Well I posted my story it wasn't really news to these Valk riders. Started walking I was lucky to have a young man stop and give me a 1 mile ride to a gas station where he worked. He took me and a can of gas back to my bike waiting for the bike to start.

[Lyle Laun]

How was the wind ? That's dropped me below 20mpg at an honest 85mph (gps) sustained running

Lyle

[Bone]

My situation it was very windy forgot to mention that your post triggered my memory.

[old2soon]

I have had my I/S git low 20s when twisting her tail and makin her scream. Full tank on my I/S got onto I-55 south outa Il. cranked her UP and went to reserve bout 122  126 miles later. Course I DID cover that distance rather Quickly!   RIDE SAFE.  bout 6 gals to r.

[Hyde]

The wind was brutal a few times which I would expect to impact it pretty significantly. The first leg was 163 miles at 80mph, I got 26. After that we were in the desert and it was 85 most of the time but I don't think I was bucking that bad of a headwind the whole time

[Hyde]

Makes me wish the big gal had OD that's for sure! Love the bike it fits me perfectly I just can't slow down quite yet 

[bassman]

Couple of very small things to check....added new/larger bags last winter????.....how much "stuff" are you carrying in the bags (weight wise).....double check the tire pressure - at least 40-42 # in the front?  I was very guilty of overstuffing my saddlebags with heavy items and probably didn't impact MPG much but perhaps a little.....never ran a car tire but tire pressure would cause a 3-4 mpg decrease if the front and rear were below 40-42 front and 42-44 rear.  NOT saying this is your problem but might be worth a little look to make sure - cheap to check.

Good luck.......

[Hyde]

I did have quite a bit in the bags but I wouldn't think it's excessive, my tool/emergency kit isn't light though. I run 41 front and 43 rear which oddly is right in the middle of what you posted. I'm still pretty beat from the ride but I'm going to make sure none of my vacuum caps came off or anything (desmogged)

[The emperor has no clothes]

I've run at 95-100, 2up, pulling a trailer. Never got that bad of mileage. There is something going on in my opinion. What's your air filter look like ?

[Hyde]

I've run at 95-100, 2up, pulling a trailer. Never got that bad of mileage. There is something going on in my opinion. What's your air filter look like ?

I haven't checked it since this winter when it looked new, I should probably make sure there isn't a mouse home in there!

[Motodad71]

Those 6 carbs get thirsty, and I too wish this amazing engine/bike had a 6 speed.

[Kokomo Kevin]

Hyde,
          I have ridden a few times out in your neck of the country and the last time I was out there
with my son on his 98 Tour and me on my 98 tour we noticed the same thing as well. Both of us run hot set ups on the dyna Tek ignition modules and are also jetted as well. We really noticed it during high speed runs through New Mexico and Arizona. Mileage really dropped above 85  MPH, another big factor was the grade/quality of the gasoline out west. Lots of high % gasohol, which also eats of gas mileage. What are you running for fuel?

[Hyde]

Hyde,
          I have ridden a few times out in your neck of the country and the last time I was out there
with my son on his 98 Tour and me on my 98 tour we noticed the same thing as well. Both of us run hot set ups on the dyna Tek ignition modules and are also jetted as well. We really noticed it during high speed runs through New Mexico and Arizona. Mileage really dropped above 85  MPH, another big factor was the grade/quality of the gasoline out west. Lots of high % gasohol, which also eats of gas mileage. What are you running for fuel?

I run premium but it is still 10% ethanol at most stations in this part of the world.

[MarkT]

I get 3500rpm at 85 indicated with an Austone tire - and at that rpm, I still get 34mpg.  Now 85 indicated is a touch below 80 actual per GPS.  The key is the rpm.  You should be getting better mileage if your rpm isn't above 3500.  Might want to have BigBF do a tuning job on it.  Couldn't hurt; he's good with carbs and I'm thinking the carbs are the problem.

[Cracker Jack]

 "You should be getting better mileage if your rpm isn't above 3500."


I've been reading all these years on this board that 3000 RPM is where the mileage goes down. Are you sure about the 3500?

[Hyde]

Now that is strange, I'm pretty certain I'm over 4000rpm at 85 indicated with the Austone at 43psi, going from memory I'll have to go confirm tomorrow

[rockbobmel]

Those 6 carbs get thirsty, and I too wish this amazing engine/bike had a 6 speed.

+1,   I rode my VT1100 on Sunday on a slab and I was surprised how the gears differ.  (engine RPM vs speed) They could have made 4 speeds out of the 5 we have and added an overdrive.

[Chrisj CMA]

Now that is strange, I'm pretty certain I'm over 4000rpm at 85 indicated with the Austone at 43psi, going from memory I'll have to go confirm tomorrow

Shift to fifth
 

Sorry, couldn't help it.   Hehe hehe

[cookiedough]

IMO,  running 85 mph which I do not do often should yield around 30 mpg, not 26 or so even loaded down with strong winds.  Seem a touch low to me.  What does your bike get running 60-65 mph should be mid 30's say 35-36 roughly?  Give that 60-65 mph speed a test run and report back if mid 30's then nothing to worry about. 

I keep mine 95% of the time between 65-70 mph near 3000 rpms on tach/speedo and get consistently 35-36 avg mpg. 

[Skinhead]

Any fuel smell?  May be hard to tell at 85 mph, but I'd double check for a small leak in the belly tank system, you could be dumping some fuel on the ground.

[Jims99]

My 99 tourer gets around 32 mpg at 65 mph. Goes down from there, at 85 mph I get about 21 mpg. I usually cruse around 70-75 and get around 26 mpg.

[MarkT]

"You should be getting better mileage if your rpm isn't above 3500."


I've been reading all these years on this board that 3000 RPM is where the mileage goes down. Are you sure about the 3500?

I consistently get 34mpg on Deerslayer and Jade in mixed riding, this for 21 years now (Deerslayer). On the open road, on trips when not pulling a trailer, I'll hold it at 3500 rpm at 85 indicated since installing an Austone - nearly 20k miles now.  Still get 34mpg on those segments. If I get much above that for any distance - the mileage drops fast.  Now that I have a Rostra electronic cruise - I expect to see the same if not better.  But I hold the speed pretty steady manually so it may not matter much.  On the Inzane ride, the bets are off since I will be pulling a trailer with a couple hundred pounds load.  IMHO, the back tire matters a lot for what mileage you get at road speeds.  Of course smaller diameter tires are the worst.

BTW George generally does better than the other 2 daily riders.  George, the blown bobber with a 205/60 Metzler on the rear, usually 35-6mpg.  But then, I usually ride George on local rides to Palmer Lake with the wife in tow on her Magna and she caps the speed to the limit or less so no high speeds.

[Bagger John - #3785]

'99 Cali-model Tourer here.

Stock smog plumbing, stock exhaust, cams and airbox. Pilots are #38s, jet needles are Cobras with the clips in 2nd groove from top and the bike has an I/S ICM. It also has a Memphis Shades Batwing and an I/S trunk.

At 70MPH I can get a consistent 40MPG with this setup @ 1200ft ASL. 80+ MPG sees that drop into the mid 30s.

I'd start checking tuning of the carbs and air filter condition, as others have pointed out. Also look at the vacuum lines and intake runners for leaks.

[Daniel Meyer]

At those speeds, headwinds and heat are dramatic factors. I've seen 20mpg on occasion in the right (wrong) conditions...

[Paladin528]

On my Trip last year I ran one day at 35 Mpg and then the next day at 22mpg.  Frist day was nice leisurely winding roads but the second day was full out on the interstate.
Once you crack that throttle she drinks like crazy.  Day 3 we cruised the back roads and was up over 35 again.  its all in the right wrist.

[Hyde]

I'm still going to check air filter and vacuum caps today but I thought about my route, a good portion of it was 4000+ feet in elevation all the way up to 6800 across the Continental Divide, and over 80 degrees all day. My hometown is 2400 feet.

Combined with the fact I usually try to avoid freeway blasts for 1000 miles straight I could have just had a bad mileage day. Thanks for all the ideas to check though I'll post back if I find anything

[Kokomo Kevin]

Elevations make sense to me, We noticed we ran pretty rich in higher elevations when we rode our trips  on the 98's. That is kinda the rub with these older pre-computer machines, they dont take kindly to elevation changes. Now Son and I both also have matching F6B's as well, and they will be making the next trip out west and the expectation for these will be better with computer controlled fuel management.

[rocketray]

you might see it it has a non-stock trigger wheel.? ?6 degree advanced one?..I was getting 17 mpg with one....at higher RPM's the advance is too far causing pre-ignition that you cannot hear...the extra oomph at low RPM is great but running out of gas on the highway is always very dangerous

[Kokomo Kevin]

I agree about the running out of fuel issue. If you are not carrying a little back up fuel in your bag, you need to out west! Found we had to really plan fuel management and when I set up route I also followed up with latest AAA fuel availability when traveling out west. We ran really close a few times only to pull into a town out in the middle of BFE, that the only station was waiting for a fuel tanker to make delivery!

[Hyde]

I haven't checked for an aftermarket trigger wheel but I will. Are they marked obviously? The bike had a lot of small mods when I got it, the Pingel, Dan-marc, de-smog was all done. I added the belly tank this winter to help on the long hauls, didn't expect to still have a 1 gallon can strapped on my back rack 

[Kokomo Kevin]

They make those small type tanks that fill the corners of the bags, just an Emergency thing!

[Hyde]

Probably going to tear the bike apart this weekend, anyone tell me how to identify and aftermarket trigger wheel?

[Hooter]

Honestly, with your additions and the way you stated you ride, I think the bike is fine. Check the filter, sync the carbs and other areas, but to tear it down if it's running fine to me makes no sense.

[Bagger John - #3785]

Probably going to tear the bike apart this weekend, anyone tell me how to identify and aftermarket trigger wheel?

Honda's will likely have a part number such as "xxxxx-MBY-yy" stamped into it. Aftermarket units won't.

Also look at tooth shape. Both the Air-Lake version and the OEM have squared-off teeth - whereas another's was more rounded.

[Hyde]

Honestly, with your additions and the way you stated you ride, I think the bike is fine. Check the filter, sync the carbs and other areas, but to tear it down if it's running fine to me makes no sense.

Because under 20mpg and 150 mile range with 8 gallons on board is unacceptable to me. If everything is fine I may just have to find a different bike which is a proposition I don't like at all, so if there is something wrong I need to find it

[The emperor has no clothes]

Honestly, with your additions and the way you stated you ride, I think the bike is fine. Check the filter, sync the carbs and other areas, but to tear it down if it's running fine to me makes no sense.

Because under 20mpg and 150 mile range with 8 gallons on board is unacceptable to me. If everything is fine I may just have to find a different bike which is a proposition I don't like at all, so if there is something wrong I need to find it

I still think something is drastically wrong. Just did 400 miles at 80-100 mph, 27mpg. Gotta go, 600 more to do. 

[Mtn Valk]

I wonder if running regular vs premium would make a difference? It's what should be used anyway. My '97 has always ran better with regular.

[cookiedough]

My 99 tourer gets around 32 mpg at 65 mph. Goes down from there, at 85 mph I get about 21 mpg. I usually cruse around 70-75 and get around 26 mpg.

wow, that seems low mpg as well.