MPG - A total let down!

[Jpainter187]

Even when I consistently keep it under 4k RPM on a full tank I still only get 135 miles out of it before the light comes on.

[riceburner]

Even when I consistently keep it under 4k RPM on a full tank I still only get 135 miles out of it before the light comes on.

That's probably not the engine's most fuel efficient speed though.

Although you do have to balance it against several negative factors:
1) the shorter top gear (than the R-R)
2) the total lack of any aerodynamic considerations on the bike
3) potential poor running due to failed stick coils/cheap gas?

Have you done the fuel-neck mod? That will give you an extra 2 litres of fuel in the tank and at least increase your range.

What other mods have you done? exhaust? fuel pump? air-filter?

I find a 135mile range to reserve rather odd tbh.

[riceburner]

Just a thought - what are you comparing the mileage to??

what was your last bike?

[Jpainter187]

Well, I have the BMW windscreen on my bike which provably helps the aerodynamics a bit, compared to stock, anyways. The only "mods" I've done that might effect fuel consumption is installing a K&N air filter.

And I'm not comparing the mileage I'm getting on this bike to the ones I've previously own at all, but just to other rocksters. My last bike was a '07 Yamaha FZ6, which is totally different. Plus I rode the FZ6 how it was meant to be ridden so I didn't even bother keeping track of my mileage most of the time.

[sweatmark]

Even when I consistently keep it under 4k RPM on a full tank I still only get 135 miles out of it before the light comes on.

The fuel warning light for R1150R is often pessimistic. We had topic threads about this back in the R1150R glory days.

My Rockster's fuel light LED shines (dimly) at around the same accumulated 130-140 miles on a full tank of gas. I ran the bike out of fuel one time with about 180 miles on the trip meter following fill-up. Contrast that with my old '02 R1150R Roadster - and its tall 6th gear: fuel warning lamp typically 160-180 miles, empty at 210-220 miles, which I tested unintentionally one time.

So your Rockster's MPG (and fuel warning LED actuation) are similar to mine.

If you want decent MPG, consider one of the F800 bikes. CycleRob has reported his results several times, up to 70 MPG. FWIW, I rode my wife's F800S during the Oregon BMW club rally a few weeks ago and got 51 MPG for 551 miles @ average 56 MPH; that's with crap gas 10% ethanol.

My Buell XB gets 50+ MPG for road riding, 40-45 PMG for WFO trackdays. So the Rockster is not exactly a high-tech efficient machine... even my buddy's /5 airhead gets better mileage, albeit with lower horsepower.

[eduardobelmonte]

In the city 41, 42 mpg.
Highway 47 solidly (70 to 80 mph) , but you can make up to 49; never 50 or more.

These numbers are one up for the city and two loaded for highway.

Many miles and trips gave me these numbers.

My bike, just in case R1150R 2004.

Eduardo.

[jas]

In townand on the freeway, a daily 36 mile commute returns 135 miles and then I get the reserve light. The bike is run between 4 and 5.5k, and I run E free fuel when I can. Two up journeys on the slab and I get 165 miles prior to the light. My last desert journey, dirt roads (about 200 miles) and the light came on at 170.

RS intake tubes, oem airfilter, y-pipe and no cat code plug, (did not come with one) plus steptoe jumper.

I might try the neck modification, but am afraid of fuel draining out the overflow tube (no carbon canister).

[riceburner]

I might try the neck modification, but am afraid of fuel draining out the overflow tube (no carbon canister).

I just get into the habit of filling up at the start of a journey, rather than the night before. (or not filling to the brim).

[jas]

[quote="riceburnerI just get into the habit of filling up at the start of a journey, rather than the night before. (or not filling to the brim).[/quote]

Good point. How many holes and how far below the top of the neck did you drill?

[riceburner]

I just get into the habit of filling up at the start of a journey, rather than the night before. (or not filling to the brim).

Good point. How many holes and how far below the top of the neck did you drill?

err - roughly 0.5 - 1 cm down from the top of the tube, 6 holes roughly 3 - 4mm in diameter (they only really have to let air through). I find it gives me about 2 litres more fuel capacity. (so I tend to ensure I'm travelling about 10-15 miles after filling to ensure I don't have fuel pissing on the floor!)

[River rat]

Last time I cruised for an extended stretch I averaged 40 mpg. This with the sport screen, sport exhaust, tank bag, Technic saddlebags, and 65mph driving E. into a 20 mph avg., S.E.. wind, one-up.(200#, 5'8") semi aggresive riding style, semi hilly, then flat Hoosier 2 lane roads. My '85 R80RT averaged 50 mpg, running 4ever. My '85 K100RT, 50 mpg under same conditions.

[jas]

Riceburner: did the drill trick, worked well.

All: just arrived inBig Sky, MT. From Boise to here, 500 miles, at an average of 70 mph, I pulled 52 miles per gallon. Best ever.

[NoRRmad]

I always had good mileage in Montana; I think it's the altitude.

[Airman]

Hmmm. What is your usual "cruising" RPM? When do you upshift?

Could be that you're running the bike at a higher RPM than will get you optimum gas mileage. Or you're hamfisted with the "fun stick." I''ve got a friend with a Rockster who rides pretty aggressively and gets mileage similar to yours (FWIW she has no windscreen on her Rock). For me, the low fuel light comes on at 145-155 miles on the odometer (depending on how full I fill the tank), and I usually get around 40-46 mpg.

I generally strive to run the bike between 3800 and 4200 around town. On the highway I'll usually run in 6th gear at 4500 or so (70+ mph).

P

I laughed when I first read this, then considered there might be a gearing difference from my Roadster. 4000 RPM puts me right at 80 in 6th. But as for the mileage, I did a hop over the Cascade range last Sat. and got 51mpg going over and 45mpg coming back over I-90. In town, (commuting) I got flog it most of the time and get 38 mpg. It has increased for some reason recently to about 41. I have 45k on the speedo.

[new2merockster]

I just get into the habit of filling up at the start of a journey, rather than the night before. (or not filling to the brim).

Actually, it is/would be best to fill up after each ride, longer ride at least. Especially if one lives in warm humid climates, coastal areas etc. That's what all pilots do after flight. Reason behind it is that when fuel level falls in the fuel tank it is replaced by warm, humid air. If left overnight, that air cools down, water condenses inside the tank on cooler tank walls, drips down and mixes with fuel. To prevent that from happening we top off the tanks to "drive" air out before plane is put into a hangar or parked for overnight stay.

Reg. my MPG. After valve adjustment and tb synch. I do get around 40MPG. Most of my driving is commuting to and back from work. Half city streets, half interstate.

[jas]

Riceburners recommendation is in regards to a filler neck that has been drilled. It only takes a couple minutes for expansion to push the gas through the overflow.

Unless I am going on long rides, I have to be careful to not top the tank off or money starts draining out!

[grwrockster]

I just got back from a week's touring 2-up in Brittany, with all the cases, top-box etc. fully loaded. I didn't bother working out the exact mileage (anyway what with the different UK & US Gallon acual mpg figures confuse), but instead just zeroed the tripmeter and used that in conjunction with the low fuel light to guesstimate how I was doing.

Even loaded, I was still consistently getting over 150 miles before the light came on every time, and was always getting more than 10 miles per litre checking the fuel pump display (as 10 miles per litre is near enough 45 UK mpg it keeps things simple to do it this way). From previous calcs I can be confident I was running between 45 & 50mpg throughout the trip.

FWIW, this was on 95 octane unleaded, the bike has 26,000 miles and the tyres were running 36 & 42 psi. I run GS Handlebars and Hand Guards, and a bar-mounted MRA Vario Screen which is mounted higher than the 'eyebrow' to provide better wind protection with the raised 'bars.

At one point, making up time to get the ferry I ran for 65 miles at between 90 & 100mph - even that fuel tank refill suggested I was around 10m per litre consumption. Overall, and given the fuel economy of many newer bikes (800 parallel twin Bimmers honourably excepted) I have to say I'm pretty satisfied with the economy and range afforded by this bike.

Given all the above, what I can't understand is how other posters are getting only 135 miles or so until reserve, while riding no quicker than I was on this trip and are riding solo? Is it perhaps the different fuel? Maybe the temperature/altitude differences? Riding style (I note that many on here like to run between 3500 - 4000rpm all the time, even in town - whereas I run the highest comfortable gear without slogging the motor at the lowest throttle opening in town and on slower roads/traffic. If there is no obstruction to progress, I'll often run 5th or even 6th in 30mph zones, rarely below 4th if I'm running at the speed limit with no problems, although I may well change down to accelerate once clear of the limit.)?

I don't know the answers, but I do know I'd have to rev my bike hard with lots of hard acceleration/big throttle openings to get the fuel light on at 135 miles - 'normal' riding generally sees between 150 & 165 miles before the light and generally just over 10 miles per Litre of 95 Octane.

[riceburner]

I just get into the habit of filling up at the start of a journey, rather than the night before. (or not filling to the brim).

Actually, it is/would be best to fill up after each ride, longer ride at least. Especially if one lives in warm humid climates, coastal areas etc. That's what all pilots do after flight. Reason behind it is that when fuel level falls in the fuel tank it is replaced by warm, humid air. If left overnight, that air cools down, water condenses inside the tank on cooler tank walls, drips down and mixes with fuel. To prevent that from happening we top off the tanks to "drive" air out before plane is put into a hangar or parked for overnight stay.

Reg. my MPG. After valve adjustment and tb synch. I do get around 40MPG. Most of my driving is commuting to and back from work. Half city streets, half interstate.

Problem with filling from an underground pump though is that the fuel is several degrees cooler - so it expands after about 5-10 mins in the tank and can overflow quite easily. That's not going to be such a huge problem (I'd rationalise) with aircraft as the fuel has been in the tanker-truck for at least an hour or few (I'd guess), and will have warmed to the ambient temp. (Incidentally - I'm assuming here that fuel isn't pumped out of the underground tanks into the tanker trucks "on demand" as it were - but the tankers are topped off regularly and are used as "mobile storage").

I do take the point about humidity though.

[riceburner]

I just got back from a week's touring 2-up in Brittany, with all the cases, top-box etc. fully loaded. I didn't bother working out the exact mileage (anyway what with the different UK & US Gallon acual mpg figures confuse), but instead just zeroed the tripmeter and used that in conjunction with the low fuel light to guesstimate how I was doing.

Even loaded, I was still consistently getting over 150 miles before the light came on every time, and was always getting more than 10 miles per litre checking the fuel pump display (as 10 miles per litre is near enough 45 UK mpg it keeps things simple to do it this way). From previous calcs I can be confident I was running between 45 & 50mpg throughout the trip.

FWIW, this was on 95 octane unleaded, the bike has 26,000 miles and the tyres were running 36 & 42 psi. I run GS Handlebars and Hand Guards, and a bar-mounted MRA Vario Screen which is mounted higher than the 'eyebrow' to provide better wind protection with the raised 'bars.

At one point, making up time to get the ferry I ran for 65 miles at between 90 & 100mph - even that fuel tank refill suggested I was around 10m per litre consumption. Overall, and given the fuel economy of many newer bikes (800 parallel twin Bimmers honourably excepted) I have to say I'm pretty satisfied with the economy and range afforded by this bike.

Given all the above, what I can't understand is how other posters are getting only 135 miles or so until reserve, while riding no quicker than I was on this trip and are riding solo? Is it perhaps the different fuel? Maybe the temperature/altitude differences? Riding style (I note that many on here like to run between 3500 - 4000rpm all the time, even in town - whereas I run the highest comfortable gear without slogging the motor at the lowest throttle opening in town and on slower roads/traffic. If there is no obstruction to progress, I'll often run 5th or even 6th in 30mph zones, rarely below 4th if I'm running at the speed limit with no problems, although I may well change down to accelerate once clear of the limit.)?

I don't know the answers, but I do know I'd have to rev my bike hard with lots of hard acceleration/big throttle openings to get the fuel light on at 135 miles - 'normal' riding generally sees between 150 & 165 miles before the light and generally just over 10 miles per Litre of 95 Octane.

Interesting.

This weekend I went up to Cambridgeshire/Norfolk border from Berkshire (around 140 miles) with camping gear (panniers/topbox/tent across pillion) and with my modded tank the green light wasn't coming on before 180miles. I wasn't thrapping it - but I wasn't pootling either - was using small roads too.

[grwrockster]

This weekend I went up to Cambridgeshire/Norfolk border from Berkshire (around 140 miles) with camping gear (panniers/topbox/tent across pillion) and with my modded tank the green light wasn't coming on before 180miles. I wasn't thrapping it - but I wasn't pootling either - was using small roads too.

Hi RB! Your 180 miles to low fuel light is pretty decent (though I know you say you're getting another couple of litres in the tank as you've done the filler neck mod, that's still good going fully loaded on minor roads with lots of stop/start, gearchanges, overtakes etc.). I've only bettered that distance once, and that was solo but loaded cruising from Maidstone Services to near Bridgend on the Motorwayat 85-ish. Allowing for your claimed extra 2 litres that should be about 18 litres used (allowing approx. 4 litres left after the light comes on)? if so, you're on similar fuel consumption (45mpg-ish UK, or 10 miles per Litre) as I was getting?

I too have done the fuel filler mod, but I only drilled 3 small holes - so it's still a pain to fill and I don't think I cram as much in as you manage. I think that it's not displacing the air fast enough and hasn't made much difference - I have to fill the last part of the tank really slowly once it gets near the neck. I plan to add a few more before Austria trip next month to make filling easier and faster with less opportunity for the expensive stuff to spurt out and splash all over the tank!

In any case - I automatically check the miles before I zero the trip and check the amount of fuel put in every time - it's a habit now. So I always have a good idea of how much fuel/distance I have left at any time, and the fuel consumption. FYI - most of my 1500-ish miles last week were on French 'D' roads - just the short blast from Bridgend to Cirencester and back, and the blast down the N12 to catch the Cherbourg Ferry from Vire were high-speed stuff (90+ mph).