Tune up discovery

[DAM650]

I've owned my boxer just over a year, riding just under 4k miles, averaging-between 34 to 37
mpg.

After completing 42k service I found the bike equipped with ngk bkr7eix iridium plugs. Over many hours of studying by reading posts and watching you tube related videos I've never run across this as a recommendation for plugs.

Could this be a source for low miles per gallon?

In my gs650 the iridium works a charm and improves response and eliminates surging.

What is the plug of choice for boxer?

[kirby]

That is pretty uncommonly low unless your flogging it awful hard??? My high mileage machine will get 42/45 normal running and I use cheap gas. Cruising at 80 on the slab with a 15 mph tail wind I have seen 50+ and with no wind average 44/45'
iridium won't make much if any difference.
Air cleaner dirty?

[peels]

that is low even with funky plugs, or even fueling problems....unless you really get on it, or sit in traffic a lot.

Curious, Are you wearing out brake pads quickly? check for a sticky rear(or front) brake. Go out, make sure brakes are cool. THEN go for as long a straight line ride as you can. and try to let the bike stop on its own, minimal braking. check disc. if its boiling hot, you have a brake problem.

My 2002 was getting 27-32mpg no matter what I did Then I flushed the brake line, and detail cleaned the caliper. I also removed ABS at that time...that should be noted.

Iv'e seen as high as 49 since that on a slower backroad trip.. and when I'm on the slab, I am generally 80-90 mph, getting low-mid 40's.

good luck.

[DAM650]

new air filter, no sticky brakes, at 85 - 100 into the wind, fully loaded with at least 100lbs and bags i did see almost 39 mpg, and yes i do ride fast, but i am not whacking the throttle wide open every chance i get, seems to go fast enough with the correct gear and just a little throttle produces plenty of intoxicating torque.

Kirby, when you cruise at 80mph are you running 5th or 6th gear?
i did a little test and ran a whole tank running in sixth at around 4 - 4,5K rpm, then running in fifth at 5K - 5.5K and I got better mileage running higher rpms.

that one i cannot explain.

again do you guys have a plug that you prefer to run?

[kirby]

100 lb loaded and up to !00, that's pretty fast. Do you have ECM gear?(counter measures). Wind screen???

Well this is a deep subject for sure. I have a friend that has a dressed HD that has a 6 speed and he can get better mileage in 5th running 80.. This is because the 6th gear is so high a ratio that the engine is not running in the ideal torque range for good power and he has to use more throttle to maintain cruise speed....the same thing is happening for you at 80/85. You are most likely geared on the 1150r at .8 for the 6th gear which would mean that at 80 your probably running 4100 to 4200 rpm. My rockster is a .7 (most are) and at 80/85 I'm running 4400 to 4500 so that 80 to 85 is an ideal RPM for good economy with that gear ratio.

If you look at the calibration of the TPS (throttle position) it is set from 0 to 5 V. I won't get into the calibration techniques (beyond the scope of this discussion) TPS located on the left TB. It send a message to the ECU of the position of the throttle and the ECU schedules fuel based on parameters and throttle position. Long story short, up to about about 1/3 throttle or so the signal is liner then as you pass that point it jumps to max V which tells the ECU your at full throttle.
This equates to about 4500 rpm on my rockster w/.7 and when I am cruising with no wind at 80 or so I am below the full throttle signal to the ECU.
I have my throttle marked so I can look at it and get a good idea of what my mileage is going to be while riding. (It doesn't matter a great deal but can make a difference of up to 10 MPG when over 1/3 throttle.
Since your geared higher .8, in 6th your not running at the ideal torque/RPM area for 80/85 and it causes you to use more throttle than if you were in 5th.
Also drag (how your loaded) plays a role! Drag increases at the square of the speed so the drag at 80 AIRSPEED and at 100 AIRSPEED could be as much as double. (80 mph ground speed + 20 mph h/wind =100 airspeeds)

You won't find this info in the BMW manuals. I have done the research on mine manually with a good digital meter. I do allot of traveling back and forth CA to AR and a bunch of it on the slab and I can predict exactly where the low fuel warning light will illuminate by the throttle position.(-+10 miles).

239K and counting.

[DAM650]

All I can say is wow. That is a brilliant and detailed explanation. thank you.

I just have the stock fly screen. Speed limit is 85 out there on I10 so 100mph plus is pretty standard, but the wind always kicks your ass once you get past Sonora heading west.

Here around home I am getting the same mileage doing short runs / commuting the same 34-39mpg.

I run premium, and mid grade mix, never get any clattering from the fuel. On the F650 the bike runs stronger and better mpg running regular, it calls for mid grade. When you say cheap gas are you running regular?

[kirby]

Yes, 87oct here. Sometimes on the road if I see no e-10 I will use premium....but rare. Only time in memory that I have seen sub 40 mpg..track day.
Since I use the trip meter for fuel, I always calculate the MPG.

[peels]

are you SURE about sticky brakes? the problem can be a dirty caliper, or gunk in the line. that when you release the brakes, they either do not release because pressure cant escape, or release slowly, sot he pads are dragging on the disc.

MPG's are all over the place for me when it comes to gas quality. that best of 49 i got, was on cheap 87. heat of the summer, ive been using 91 or 93. depending on the gas station. getting 40mpg almost exactly every time. I ride pretty quick in commuting. and even do a small power wheelie every now and again. LOL

is there any engine running problems that accompany the mpg problem? rough idle, vibration..anything like that?

kirby I like the idea of the throttle marking

[kirby]

Mileage, like tires, are tied closely to how you ride. I can tear off a set of Ravens in 2500 mile riding with the sport guys for a fast pace week but if I am in normal mode and smooth on the throttle and brakes W/ few quick accelerations and heavy braking I can get 6K/8K out of them.
Practice being smooth w/ not so many jack rabbit starts if mileage is a concern.

If you look down at your throttle when cruising at 80/85 and you see that your over about a third...you MPG is going down.
Cheap gas is the FRESHEST stuff they have and I buy , if possible, from the majors(oil co) cause they tend to sell to the discount, mom and pop 7/11 type places their old stuff and the fresh in their stores. Hardly any difference between 89/91 (according to friend in the business).
87 oct has higher BTU as well so if your not running into bad pinging(rare), then maybe a bit more economy.
And of course no ethanol when you can.

FWIW

[peels]

Mileage, like tires, are tied closely to how you ride. I can tear off a set of Ravens in 2500 mile riding with the sport guys for a fast pace week but if I am in normal mode and smooth on the throttle and brakes W/ few quick accelerations and heavy braking I can get 6K/8K out of them.
Practice being smooth w/ not so many jack rabbit starts if mileage is a concern.

If you look down at your throttle when cruising at 80/85 and you see that your over about a third...you MPG is going down.
Cheap gas is the FRESHEST stuff they have and I buy , if possible, from the majors(oil co) cause they tend to sell to the discount, mom and pop 7/11 type places their old stuff and the fresh in their stores. Hardly any difference between 89/91 (according to friend in the business).
87 oct has higher BTU as well so if your not running into bad pinging(rare), then maybe a bit more economy.
And of course no ethanol when you can.

FWIW

yep dont use ethanol in machines that sit. my boat and bike.... dont care in cars though lol agree, on the freshness comment.....

I can tell when the MPG drops by vibe change. Load vs torque. My bike has a happy spot mid 70's to low 80's in 6th. Depending on temp, hills, load, i can feel in the bars when the engine goes from working hard to where its in comfort zone, then back again above 90. hard to explain... but you give it throttle, get above that speed, feel the vibe change, then drop throttle, and speed doesn't drop at all. I'm a sport shield, always with system cases. In a tail wind once, with ZERO load, empty cases, that speed was +90.

I generally don't worry about it unless i'm on a long ride, when thats part of the fun for me. I really love these engines...I got another "how can you tell its running?" comment the other day lol

[DAM650]

Hey Peels.

i tested the wheels sticking and no issues.

After I this talk I am thinking about TPS now? And gonna throw a new set of plugs in there, and gonna run some tanks of 87 and see what I get.

I appreciate you folks taking your time to discuss with me.

thanks again

DAM

[DAM650]

much the same mileage running 87 octane and new plugs since the last posting above

[towerworker]

I think you guys need to flush the radiators and put some new antifreeze in. Bike's not running at the correct temp.

[DAM650]

the gift that keeps on giving. just copy and paste

[sykospain]

For sure, kirby is a gem - what expertise !

On my UK Rockster I get an average fuel consumption of circa 50 mpg, riding like an old git. I never select 6th gear at any speed less than 90 mph - and those are English miles, not US.

DAM650, your steed needs a good coat of cleaning, stroking, brushing-down and polishing.

Coz there's summat up with it.

"Britain and America- 2 countries divided by a common language..." Winston Churchill, 1940.

[DAM650]

syko

throttle tps reset mileage update coming after i burn up a tank of cheap gas

[skylarmav1]

As part of my ongoing learning on this forum, I changed to the Autolite AP3923 spark plugs on my 02 Beakster. Not only did it virtually eliminate the infamous suge between 2,200-3,000 rpm, but millage gained some 15%.

Just a little nugget thay may help.

Best of luck...
Skylarmav

[Hyja1]

Hey Skylarmav, were those autolites the standard copper plugs? Or are they platinum, iridium etc...

[skylarmav1]

They were standard. Nothing special.

[sykospain]

Hi skylarmav,
I'm intruiged by your preference for those Autolites; for a one-spark bike obviously, not a twin-spark like my '04 Rockster.
The plugs are available here in Europe from a dealer in France at six euro each ( about 8 of your bucks ), says the infamous no-tax-paying Google monster.
So I wonder if it'd be worth my while trying a pair in the top holes, in view of the improvements you claim.
AL in s.e. Spain