RSTD + Windscreen + Superslab = Brutal MPG

[Sunman]

I had a real shock today. I have a 2006 RSTD and I do 95% of my riding with no windshield. That was one of the reasons I got it. I like the bare cruiser look most of the time. Today I knew I was going to be doing a straight highway run, so I thought I would put the shield on, and take a nice easy ride. Well, I have put almost 1000 K on the bike in the last 3 days, and just like last year, I was getting about 280 - 300 KM out of a tank. Well, today on my ride I filled up, reset my fuel odometer on my Garmin 550 as usual and reset my low fuel indicator. 170 KM later, my Garmin shows just under half tank, and my fuel gauge on the bike is on low fuel indicator again. This is the worst fuel economy I have had since the bike was new. Now, I was also going faster than my normal rides, where I generally stick to the back roads, and keep it between 80 and 90 KM/H. I had the cruise set at 114 (by garmin, 122 by speedo) my first thought was that the windscreen caused this horrible mileage. I will have to check it again, with the windscreen off. I know that I rode with the windscreen on last year to North bay, which is about 5 hours, and I do not recall the mileage being that bad, but again, most of the highways are 80 KM/h limit, where I do 90ish. Anyone else found this kind of bad mileage with the windscreen?

[Guest tx2sturgis]

 

 

If I tried to convert all those facts and figures to something I can understand, my head would explode. I was under the impression there would be no homework on this website. Sure seems like some kind of algebra/trig/geometry/long division math problem in high school. No sirree...not gonna tackle this one fer ya.

 

Good luck!

[Monsta]

Brian, if you change your mind just multiply all his numbers by .621 to covert them to miles.

 

*****

 

I figure you were getting around 21-25 MPG (US). That's pretty bad. Not sure if the windshield is totally at fault here since my heavily faired RSV has the gianormous windshield from Yamaha's catalog PLUS I pull my trailer 90% of the time and I still average 32 pulling.

 

Might have just been headwinds??

[midnightventure]

There is a big difference between running 70mph and running 60. But less than 30 on these bikes is terrible.

[stardbog]

Bad gas, Bad Spark plug, wire or coil? Did you ever take bike for service? Have you sinc a carbs?

 

That's really bad LPK (Liters Per Kilometer) And no its not windshield related. Only other think is wrist disorder

[flb_78]

I've been getting around 27mpg this year out of my Venture. Most of my 17 mile commute to work is open highway where I run 80mph, and this is a speedohealed true 80mph.

 

I don't know how folks are claiming 40mpg on these big bikes unless they never get the machine into the power band and never go over 60mph and haven't speedohealed it.

 

Best I ever had was 37mpg and that was running 65mph with a 40mph tailwind. My buddy on his BMW was getting over 60mpg on that leg of the trip.

[Dave77459]

I run with the windscreen on all the time. Doing 115kph/70mph with any headwind, I will frequently see the low fuel indicator at 170km/105miles. On backroads doing 95kph/60mph, I will see the low fuel indicator at 195km/120miles.

 

I do know that resistance increases with the square of velocity, so going from 95-115kph/60-70mph will have a huge effect. The windscreen does increase the surface area, so that too will have a big effect.

 

I always marvel at the folks who see 77kpg/48mpg because I have never come close to that. 55kpg/35mpg is about the best I've ever managed, even with a fresh tune-up. I figured I was hard on the throttle, and I am.

[V7Goose]

I've been getting around 27mpg this year out of my Venture. Most of my 17 mile commute to work is open highway where I run 80mph, and this is a speedohealed true 80mph.

Even at the speed you state, you have something wrong with the bike if you are under 30 MPG. I would expect 32 - 34 under those conditions on a fully loaded RSV (without significant head or cross winds).

Goose

[Brake Pad]

43 one up,

41 two up

& 34-35 pulling a loaded trailer

[GeorgeS]

I would start by pulling the plugs, and see what they look like.

 

Run a can of sea foam, drain the carb bowls a couple times, new set of plugs,

and do a Carb Sync.

 

Also, check the Choke linkage to all 4 carbs, make sure no problem there.

 

Air filters ??? are they clean

 

Way to low on the MPG.

[Scooter Bob]

I don't know how folks are claiming 40mpg on these big bikes unless they never get the machine into the power band and never go over 60mph and haven't speedohealed it.

 

If we stay on the backroads, 2 up loaded with camping gear, we were getting 45-46mpg day after day. Put 500 on last weekend, mostly interstate at 65-70mph, and got 41-43mpg.

 

How many miles on your scoots?? Ours didn't start getting above 40 mpg until around 40k miles, yours might not be broken in good yet.

 

Scooter Bob

[RandyR]

on my new RSTD (1 up, w factory windshield) riding north on hwy 441 along the west side of the Okefenokee swamp. ie: flat, straight highway with few stops at an average speed of 65 mph (using cruise control), I got 44 mpg. So I'm guessing that is best case for my bike with the windshield on.

[midnightventure]

I get better mileage 2up than by myself. That is probably because I ride safer when I have my wife with me.

[ManWithAVision]

I ride some of the same areas as you do. I took my windshield off for the first time on Friday and ran up the 427 early in the morning, around town during the day, and along the QEW in the afternoon. It was a bit breezey and I have to say I felt like I had an elephant on my chest on the highways from all that wind pressure at 120 KM / HR. Got behind a couple of large transports on the QEW and along with a head wind and their backwash I had to keep a firm grip on the grips. Don't know how those Harley chopper guys can do it all the time and continue to look so cool and relaxed.

 

Based on my windshieldless experiences I would think that your upper body probably provides more wind resistance than a smooth curved windshield when it comes right down to it.

 

I only have 1,450 KM's on my new engine so far, so I'm not even going to think (or worry) about gas milage at this point, but my wife and I did a two up ride to the Forks of the Credit and Erin yesterday (mostly at 80 - 100 KM / HR) and I did set the trip meter. We topped up the tank before we left and we put just over 100 KM on the trip meter. Upon our return my gas guage had lost one bar. So overall, I don't think we did too badly.

[MAINEAC]

On my way to CA from GA I hit some serious headwind through NM & AZ... I could barely maintain 70 MPH (actual with GPS) with almost full throttle... This was riding solo and pulling my Piggybacker trailer... When I tried to pass big trucks I'g get about at the driver's door and the wind coming off his truck was like hitting a wall and a few times I got stuck there and would have to downshift to 4th and give it full throttle and when I'd finally break through it was like being shot out of a cannon... Never seen wind like that before... That 450 mile stretch I was only getting 20 MPG... I hope I get a tailwind on my way back to FL..

[BobanVal]

I got 50 mpg on a trip from Nova Scotia to Huntsville Ontario and back. Two up and both saddlebags loaded and a tailbag. I stuck to the speed limit.

I generally get 43 mpg "around town".

[ABean]

I've got a 05rstd I got better mileage as it got broke in 25000km and better at35000km I get around 40 to 43mpg with 1 up I also reset the carbs at about 5000 km.

[5bikes]

Brutal spring winds in the desert Southwest are a norm. Though this year has not been near as windy as prior years, 20-50 mph is not unusual for months. Last year started mid Feb, ended in early JUNE. With the dust blowing it can be hard too see across the street. Paint and windshields get pitted bad in just a few years. I avoid those days outside but then I can being retired.

But then again we ride year around....

Maineac I bet you do too

 

Oh by the way I get ticked if any of my 5 bikes don't get 45 mpg!!!

Edited April 21, 2009 by 5bikes
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[Marcy]

 

 

If I tried to convert all those facts and figures to something I can understand, my head would explode. I was under the impression there would be no homework on this website. Sure seems like some kind of algebra/trig/geometry/long division math problem in high school. No sirree...not gonna tackle this one fer ya.

 

Good luck!

 

I'm laughing so hard my stomach hurts.

[flb_78]

Even at the speed you state, you have something wrong with the bike if you are under 30 MPG. I would expect 32 - 34 under those conditions on a fully loaded RSV (without significant head or cross winds).

Goose

 

I weigh around 400lbs, usually have 50lbs of crap in the bike and usually get 6-8000 miles on a rear motorcycle tire.

 

My throttle is an off/on switch.

[mraf]

The math conversions are a pain but what sends me over the top is the electrical wizards talking shop talk. Whew, to much information, overload, eminent brain shutdown!:rotfl:

[BradT]

Well, I have put almost 1000 K (600 miles) on the bike in the last 3 days, and just like last year, I was getting about 280 - 300 KM (175-188miles) out of a tank. Well, today on my ride I filled up, reset my fuel odometer on my Garmin 550 as usual and reset my low fuel indicator. 170 KM (106 miles) later, my Garmin shows just under half tank, and my fuel gauge on the bike is on low fuel indicator again. This is the worst fuel economy I have had since the bike was new. Now, I was also going faster than my normal rides, where I generally stick to the back roads, and keep it between 80 and 90 KM/H (50-56 MPH). I had the cruise set at 114 (71 MPH) by garmin, (122 (76 MPH) by speedo) my first thought was that the windscreen caused this horrible mileage. I will have to check it again, with the windscreen off. I know that I rode with the windscreen on last year to North bay, which is about 5 hours, and I do not recall the mileage being that bad, but again, most of the highways are 80 KM/h limit, where I do 90ish (50-56 MPH). Anyone else found this kind of bad mileage with the windscreen?

 

How much fuel in Liters or gallons did you put in, that is needed to determine your mileage (remember Cdn gallons are biggger than the US ones)

 

Higher speeds change the mileage quite drastically,

 

Brad

[bj66]

went on a ride yesterday with 2 H-D street glides, and 1 gold wing. approximately 90 miles round trip. rode into a 25 mph wind on way out, when we got back we all filled up our tanks together. My rstd used almost a half gallon more gas than the others. We rode pretty hard on the way back, but everybody rode the same.

[Sunman]

How much fuel in Liters or gallons did you put in, that is needed to determine your mileage (remember Cdn gallons are biggger than the US ones)

 

Higher speeds change the mileage quite drastically,

 

Brad

 

Thanks for all the conversions Brad. I just checked my receipt, and when I filled up, I added 17.142 Litres of regular gas. (4.528 US Gallons) So if my calculations are correct, that would mean that I got about 23 MPG. However, when I filled up, I was at almost empty, my low fuel (2 bar) indicator has just come on, so I probably have about a gallon more fuel left in my tank than I did when I filled up. So, adjusting for that gallon (give or take) I would estimate my MPG to be 30.1. I still think it sucks. I am used to 275-300 out of a full tank. so 170 makes me mad. I really want to test this at my normal speeds. If I can get my regular mileage back, I will attribute the poor fuel economy to a combination of my windscreen and my speed.

[Midrsv]

On my RSV I rarely get above 35 to 37 MPG and a lot of times I'm in the 32 MPG range and that is with a speedohealer corrected odometer. I ride with Gold Wings and Harleys and they all get much better mileage. I typically use at least 1/2 gallon more at fillups, with or without wind. If you are running a RSTD or RSV without a corrected odometer/speedometer you should keep in mind that you are actually getting 7% to 8% less mpg than you think.

 

DT

 

PS. Last summer riding across Kansas in the wind I got down to about 22 mpg and it was brutal.