MPG questions.

[Bolle]

Hey all. So I am getting horrible gas mileage. I was hoping for 42 mpg since most people seem to be getting that, but so far its as follows:

87: 32 mpg (and knocks)
89: 32.2 mpg
92: 32.7 mpg

Now I have switched to synthetic oil

89: 32.3 mpg

I saw some of you guys got 36 mpg, but this 32 crap needs to stop.

I cleaned the air filter and will be checking if that makes a difference. It turned out my bike came with a K&N filter on it, which was a pleasant surprise (Only had this thing about 600 miles now.) But the filter didn't seem horribly dirty (Albeit its half the size of my former 650cc rice rocket.)

So on to the questions I have. I noticed in other posts a lot of talk about grades of gas used. Here in the states premium is 92, but I believe some of you mentioned running higher octanes then that.

Also, does cold have as large an effect as some of you have mentioned? I have been riding in around 40F weather this whole time. But I have never seen huge effect in any other vehicle I have ever owned.

Granted, I have seen maybe a 5% change, but I thought that was just a result of winterized gasoline.

The activated carbon canister was removed at some point, and the pipes are just kinda hanging there. I am kinda curious about that. I don't know what it does exactly and therefore cannot speculate as to what its removal would do. But could this be leaking gasoline?(or allowing vapor to escape)

The bike has stock exhaust, with cat. Stupid little things that can shave mileage like tire pressure and spark plugs have been checked. Most miles are from my 55 mile highway commute, the last tank was after the switch to synthetic and an enjoyment ride being a little harder on the throttle.

Thanks all.

[bill pierce]

I average about 48-50 mpg highway if I keep it under 70. That is with 92 oct. Remas exhaust and K&N filter, synthetic oil in engine, trans and final drive.

carbon can removal will have no effect, unless you over fill the tank and dump fuel on the ground.

I would say adjust the valves and sync. the throttle bodies and see if that helps.

[Bolle]

Hmm, the 55 mile commute is on roads with posted speed of 55 mph (I end up at around 65 most of the way.) I fill it up to the brass on fill up. Use the bottom of the brass as my gauge so I fill it to the same level every time. That's not "over filled" is it?

Did the valve adjust. There is very little vibration, so I didn't feel I needed to sync. But I'll give it a shot.

I don't know how it could possibly be related but there is an issue with the low fuel light being just flat out quirky. Turns on and off when ever it damn well pleases after about a gallon has gone by. I don't know what that could do with it.

Think maybe it would be worth while putting a balloon on those fuel lines just to see if there is any significant leakage?

There is no excuse for a 25% difference in mpg. I mean, something has to be wrong, right?

[timbox2]

And I think my 38-39 average is crap, though I have seen mid 40's on the highway. Funny thing is Air filter would have normally been my first thought, until I changed mine from a really dirty nasty stock one to a K&N, bike definately ran better,plug colour changed from sooty to a nice grey, but MPG, hardly any difference???


Only other thought is has bike been chipped and had a stock exhaust put back on to sell to you?? Or has the motronic coding plug( In left fuse box) been removed or played with, I believe that can have quite dramatic results on fueling.

[timbox2]

Just had another thought, your not physically losing it are you? I know that if I fill mine right to the top I get a fair bit drip out of the overflow, now I assume that on the carbon can bikes those pipes go to the canister? Or do you still have an overflow pipe down by the swingarm?

Just a thought and if you are filling up again after a 55 mile commute the ratio of fuel lost might bring the MPG down, have you run it nearly dry and checked MPG over a full tank?

[throttlemeister]

Tim, are you comparing US mpg with UK mpg?

Bolle: Mine did 32mpg (37mpg UK) too when I got it. Didn't matter one bit how I rode the thing, always 32mpg. I then did a few things. I got a Staintune exhaust, a chip from Fobert Foster (NY) and a proper throttlebody sync.

Now I get an average of 40mpg (47mpg UK), while having much more power, dramatic faster acceleration, much less vibration and drooling sound. When just cruising, I can get up to 50mpg (59mpg UK).

Sounds counter intuitive, but proper fueling (stock is VERY lean) really makes the bike run good and a lot more economical.

[r550s]

always managed 145 miles (just) between fill-ups - which was four heavy-handed return journeys to work on motorway & a-roads. Worsened rapidly one winter and I found myself pushing it with just 132 miles showing. That worked out at 33mpg. Took the beermat-sized K&N out & it had become very blocked very quickly - winter crap.

[Bolle]

Great point, Meister. I have been paying attention to people's claimed locations because I knew there was some difference between imperial and US gallons. But I actually wasn't sure about how much. (Guess I should have googled it, I mean the computer is right in front of me.)

I like the can change idea downside is though, I really really really desperately want to avoid a loud can. I LOVE loud cans, but already in the first 600 miles I can tell that the pigs loved my old bikes loud can too. I was very close to losing my license with my old bike and I very rarely went 5 over the limit. I think I got their attention, jap v-twin was louder then most Harley's

But I'll keep a lookout for a new comp on ebay. I had just missed out on one for cheap not to long ago. So I'm sure I'll see another.

Tim, I don't think the guy had a different exhaust on it. He was shocked to when I pointed out his missing charcoal canister. Plus I see no signs of it being removed at anypoint. And, yeah since the fuel gauge is all outta wack I just fill up at 140 miles so I am getting about a full tank.

But I will put a jimmy hat on those tubes and throw it through some twisties and see if any gas starts flowing out.

Curious, anyone know if there is a decent way to flash the bios. Hell any cheap ways to emulate the code reading unit?

[r550s]

if you're on about reading the fault codes - try googling 'rob lentini' - he's put together some useful info which includes using a voltmeter to read the fault codes.

[throttlemeister]

Bolle, the Staintune with the spuds in is only slightly louder than stock but it sounds much darker and throatier. It definitely doesn't attract attention from the law. It is one of the best exhausts out there for the S, albeit an expensive one. I bought mine from a member here. If you can find one used, that'd be a good option.

[Lars1974]

hi guys,

i am getting between 35 and 40mpg. i keep track of it ever since i got the bike. mpg seems to be best when fully loaded and going on motorways at steady speed. i got up to 55mpg when touring....

i on my own normally 38-40mpg...

thx Lars

[Bolle]

Alright, air filter cleaning helped quite a bit. Horrible engineering on the how to get to it. What a pain in the rump. Now I get about 38 mpg so that sounds more like what I would expect considering the miles on it. Another thing I have started doing is leaving it on its center stand ALL the time. I don't smell nearly as much gas vapor in my shed anymore and it no longer smokes at startup.

Anyone know if any bells or whistles go off if the cat starts breaking down? I was thinking about its probably going south. Might want to get it in a burlap sack and chuck it in the river soon.

[moon]

I'm assuming that your valve clearances, cables, sync are all up to snuff.

I am usually getting 40-42 commuting in traffic but sometimes a little worse when getting "enthusiastic" with the right hand.

Touring 2 up usually about 44-47 as I can't go errrrr too slow but up at altitude (Wyo, Colo etc) I have had as much as 55+ going over 220 miles before stopping to fill.

Stock pipe, no canister

[Blackal]

A safe average for the boxer engine is 10 miles per litre. I know it is mixed units, but since you have an 18 ltr tank and fill up in ltrs - it makes sense.

I liked the US sports commentators, who remarked on the judges at the javelin-throwing contest:

"The judges have their yardstick out Bill"

"Yeah Fred - but you gotta remember.......... they're using a metric yardstick"


Al

[Bolle]

So all the maintenance (filter, sync, valves) where done and good and I was still getting 35 mpg (American) average.

Side note, Don't trust my local dealer anymore, all the maintenance was supposed to be done at 12k I bought it at 14k. Have the receipt from the former owner. The sync was WAY off, the valves where horrible, and the airbox was full of crud. So if you near Maryland, Don't go to Bob's BMW.

Anyways, So I thought about it, the former owner told me that the bike was a tester bike at BMW America headquarters till he bought it in 2005 (so 3 years) and the sales receipt says it only had about 2k miles on it. So it had to have sat alot.

With my new knowledge I set off to find a solution to 3 years of gasoline varnish and carbon cement that probably formed in that poor old engine.

Most fuel injector cleaners are crap. Just octane boosters with maybe a hint of detergent. Makes the engine run real well, till the octane booster is out of the tank.

Tried a couple of different things like seafoam to see if it would help. No dice. I was coming to terms with the fact that I was gonna have to rebuild the engine to get it running well when I came across the reason for this post.

Found this stuff called Lucas Oil Fuel Treatment. I had heard of Lucas Oil before and knew they had a good rep, but what got me about it, it was literally oil looking. I thought "Wow, thats weird. If I'm gonna rebuild what would hurt to poor a little oil in my tank."

Taking off the cap, the stuff has absolutely no octane smell to it. It really is just like a very lightweight oil Poured a bunch in the tank and let it rip.

First 30 miles or so I had a bit of knocking, then the deep vibration in the engine went away, giving way to a more "tinny" vibration. By 50 miles I felt more throttle response and (I shit you not) it felt like 10 ponies getting restored. Literally scared me a little at first. I then spent the next 90 miles riding like a total jackass cause I was so thrilled to have the damned thing running like that.

The next shock came at the pump, After spending the better portion of the tank either waiting at a light or slamming the throttle to get to the next one I got 40 mpg on the tank.

Fresh gas made the "tinny" vibration go away and left it feeling smooth as silk (well as smooth as you can expect from an R engine) Down side I now know what that "power surge" everyone always bitches about is. I guess I didn't generate enough power before to feel it surge.

The fresh tank made 40 MPG as well, and I am officially a Lucas Oil fanboy now.

This weekend I'm gonna change all my fluids since I think I probably have some gunk in the oil now, and want to get my gearbox and shaft on synthetic, so I'll try some other lucas stuff and tell you guys how that goes.

Also I bought a crazy oil filter that is washable, I'll review that now that I'm gonna be breaking it apart and seeing what it caught and how big of a pain it is to clean.