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Thread: Why am I getting only 25mpg?

  1. #46
    Registered User bluehole's Avatar
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    YOU HAVEN'T BEEN EMASCULATED TILL YOU PICK UP A RED VESPA AT A HARLEY DEALERSHIP FULL OF HARD CORE BIKERS!!!


    Stop it. You're killing me.
    2000 R1100RS
    1972 R75/5

  2. #47
    Left Coast Rider
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    Quote Originally Posted by wineguyd View Post
    On a side note...I had a Vespa GTS250 that I bought from a different HD dealership that picked up Vespa as a sideline.
    I'm giving you points for even admitting you own/owned a Vespa.

  3. #48
    WineGuyD wineguyd's Avatar
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    Quote Originally Posted by bluehole View Post


    Stop it. You're killing me.
    True story, and to make things worse, I was hoping to get the scooter from their garage in the back, but no, they insisted on wheeling it out the front door and plopped it in front of a dozen Hulk Hogan types and gave me the key.
    Purveyor of fine wines & spirits
    Rides a 1996 R1100R

  4. #49
    WineGuyD wineguyd's Avatar
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    Quote Originally Posted by BC1100S View Post
    I'm giving you points for even admitting you own/owned a Vespa.
    I actually loved that scooter! Did 85mph on the highway and got 65mpg...the Italians call it "sprezzatura".

    I sold if after almost getting killed by a deep pot hole, realized I needed bigger wheels.
    Purveyor of fine wines & spirits
    Rides a 1996 R1100R

  5. #50
    Registered User bluehole's Avatar
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    Don't get me wrong. I like scooters, but the visual is killing me.




    they insisted on wheeling it out the front door and plopped it in front of a dozen Hulk Hogan types and gave me the key.
    Attached Images Attached Images
    2000 R1100RS
    1972 R75/5

  6. #51
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    There are signs the shop is not top notch but its the guy with the wrenches that counts, not the service manager.

    Dieselyoda has given you the best advice in this thread- stick to basics to get a direction.

    But you need to understand this complaint is often a red herring from a customer who hasn't even measured the mileage accurately and the shop is probably used to seeing some of that. If you did it over a whole tank with accurate measure of miles that's good but a gallon or two with "maybe miles" is worthless...If it is real, the proper first suspects are any stuff touched or impacted by last service.

    My first thoughts went to vacuum issues and dragging brakes...either could have been impacted by work done BUT not necessarily the fault of the mechanic. The idea of jumping to cat code plugs as a cause is silly- it was never touched during a normal service and whatever state it went in is how it came out, so cannot explain any sudden change.

    If your master cylinder had serious corrosion at the seal it indicates serious brake system neglect and perhaps a poorly sealed m/c allowing moisture into the system. Both old dead rubber hoses and gum formed at the pistons (will not be removed by a normal service- takes a caliper rebuild or replace) can cause brake drag. Brakes drag a small amount anyway when in good shape- the diagnostic is simple- raise the front or rear wheel in N and rotate- if it turns easily by hand with no more than modest brushing of the rotor its fine- if its really hard to turn its hung...Another sign is a badly blued or discolored rotor- showing rotor temps exceeded about 1050 F (takes serious track duty or stuck pistons to get there). Absent one of those, its not your brakes..Rear calipers can stick for other reasons and rarely pads can be put in wrong or stick due to manufacturing issues- but this is more often the mistake of a home mechanic than a shop..

    Failure to put plugs back on throttle bodies after a synch is common. If synch wasn't checked or done they wouldn't have been touched at last service.

    Failure to use all 6 gears can certainly cause crappy mileage but if you're a regular rider that ought to be off the list of likely cause.

    So can a hung injector from sitting too long with crappy fuel but that ought to be seen as smoke, dumping raw gas after start or similar..Not a visible leak but an obvious sight or smell. A rule well known to real mechanics is a whole lot of things idiots think somewhere in the fuel system are really simple electrical or vacuum issues easily found by those who understand...always suspect those who want to start with the fuel system without a real justification.

    An so can a bad ignition but the crappy starting and running ought to be obvious if its disrupting mileage that much- at least to any experienced test rider..(The HES on oilheads is infamous for wire failures, for example)

    Any good shop saves old parts to show customer- both as education for customer and to show they've done decent work- they are after all the customers property...That parts guy is worthless and you should remember that- but using his time so you can go elsewhere isn't exactly fair play either and that's your fault. The Max parts fiche will get you anything you need- learn to use it. Save the "help me but I want to buy elsewhere" stuff until you're a well established customer and known at the dealership- then you might be surprised how much you can learn from those guys. Good parts guys can show you how to save some coin and will- and they're proud of their knowledge that let's them do that- its not in textbooks and comes from experience.

  7. #52
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by racer7 View Post
    ... The idea of jumping to cat code plugs as a cause is silly- it was never touched during a normal service and whatever state it went in is how it came out, so cannot explain any sudden change.

    Just FYI, CAT code plugs were not jumped to as a cause. Just part of the configuration that should be known on an R1100 since it is unique with the Open Loop map, also, many R1100s have been altered with Techlusions and TPS adjustments looking for a "cure" for surging ... I should have thought to ask about Blue paint on the TPS screws.

    I have no disagreement with Dieselyoda's suggestion for a systematic approach.

    Here's what the OP said, "With the bike back and tuned I've done two tanks and averaged 25mpg per tank." That's an awfully big drop and poor mileage, don't you think? The brakes dragging thing is interesting, I'm curious how this turns out.

  8. #53
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    Well...An earlier comment brought to mind a known problem - the oil temp sensor. I have seen several threads here, there, and everywhere that have pointed to the oil temp sensor (from Paul Glaves, maybe??).
    If the temp sensor is bad, it signals the motronic to run rich. You can get one through Max BMW. Easy repair.
    Also - irt the master cylinder. The mechanic is correct - if there is more than light pitting they cannot be rebuilt.
    BTW - my '98 RS gets 41 mpg at sustained improper, but entertaining, speeds (i.e. a speed that would be 15 over the speed limit on that new toll road in Texas).

  9. #54
    WineGuyD wineguyd's Avatar
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    Quote Originally Posted by racer7 View Post
    There are signs the shop is not top notch but its the guy with the wrenches that counts, not the service manager.

    Dieselyoda has given you the best advice in this thread- stick to basics to get a direction.

    But you need to understand this complaint is often a red herring from a customer who hasn't even measured the mileage accurately and the shop is probably used to seeing some of that. If you did it over a whole tank with accurate measure of miles that's good but a gallon or two with "maybe miles" is worthless...If it is real, the proper first suspects are any stuff touched or impacted by last service.

    My first thoughts went to vacuum issues and dragging brakes...either could have been impacted by work done BUT not necessarily the fault of the mechanic. The idea of jumping to cat code plugs as a cause is silly- it was never touched during a normal service and whatever state it went in is how it came out, so cannot explain any sudden change.

    If your master cylinder had serious corrosion at the seal it indicates serious brake system neglect and perhaps a poorly sealed m/c allowing moisture into the system. Both old dead rubber hoses and gum formed at the pistons (will not be removed by a normal service- takes a caliper rebuild or replace) can cause brake drag. Brakes drag a small amount anyway when in good shape- the diagnostic is simple- raise the front or rear wheel in N and rotate- if it turns easily by hand with no more than modest brushing of the rotor its fine- if its really hard to turn its hung...Another sign is a badly blued or discolored rotor- showing rotor temps exceeded about 1050 F (takes serious track duty or stuck pistons to get there). Absent one of those, its not your brakes..Rear calipers can stick for other reasons and rarely pads can be put in wrong or stick due to manufacturing issues- but this is more often the mistake of a home mechanic than a shop..

    Failure to put plugs back on throttle bodies after a synch is common. If synch wasn't checked or done they wouldn't have been touched at last service.

    Failure to use all 6 gears can certainly cause crappy mileage but if you're a regular rider that ought to be off the list of likely cause.

    So can a hung injector from sitting too long with crappy fuel but that ought to be seen as smoke, dumping raw gas after start or similar..Not a visible leak but an obvious sight or smell. A rule well known to real mechanics is a whole lot of things idiots think somewhere in the fuel system are really simple electrical or vacuum issues easily found by those who understand...always suspect those who want to start with the fuel system without a real justification.

    An so can a bad ignition but the crappy starting and running ought to be obvious if its disrupting mileage that much- at least to any experienced test rider..(The HES on oilheads is infamous for wire failures, for example)

    Any good shop saves old parts to show customer- both as education for customer and to show they've done decent work- they are after all the customers property...That parts guy is worthless and you should remember that- but using his time so you can go elsewhere isn't exactly fair play either and that's your fault. The Max parts fiche will get you anything you need- learn to use it. Save the "help me but I want to buy elsewhere" stuff until you're a well established customer and known at the dealership- then you might be surprised how much you can learn from those guys. Good parts guys can show you how to save some coin and will- and they're proud of their knowledge that let's them do that- its not in textbooks and comes from experience.
    Some good points but....

    -Mileage was calculated on three full tanks before and three full tanks after.
    -TB's were synced by them.
    -they were paid a grand to check, tune, adjust, and replace everything possible. If they overlooked something...fine...it happens...but they are already hitting me for more money when I think this return diagnostic should not be something I pay for. If they find something else went wrong afterward then we'll deal with that cost but to tell me they want $100 to find out why my mileage dropped 30% after getting it back AND why the bike wouldn't start after they took it in the shop to run some test is dead wrong in my book.
    Purveyor of fine wines & spirits
    Rides a 1996 R1100R

  10. #55
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    The shop should of course wave the charge if what is found was their fault.
    But there is no reason they should do the diagnosis for free if it simply is one of the things that can happen without their intervention- like brake hoses (written up by several over the history of these bikes and one of the reasons BMW now uses lined, covered stainless for all new bikes) or gummed piston seals.

    Lots of time turning wrenches doesn't leave me a big believer in coincidence which is why looking at last work is the place to start diagnosis but that will almost automatically cross into other areas. Whether to charge nothing, part, or all for results should depend on what is found- I'd bet you'll find them willing to cover most or all of a diagnostic charge if it traces to their work. I'd bet the outcome as about even up between it being their fault and just a "stuff happens" cause bsed on my past adventures with stuff like this.

    Sounds like you've got a solid measure of mileage so your decrease is very real and no red herring issue.
    FWIW, the lowest numbers I've ever been able to push an oilhead down to were low-mid thirties and I'd be looking if any of the ones I've maintained hit 25..Only older stuff in the fleet these days (other than a Transalp) are a R1100S and a K1200RS, the last with possibly the best motor BMW ever made..

    I would not expect tire pressure, chassis alignment or similar to cause this much of a decrease without it being very obvious to anyone not a total newb..

    I also wouldn't expect a bad temp sensor to reduce mileage that badly- that's a lot of extra fuel being pumped in...

  11. #56
    Registered User roger 04 rt's Avatar
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    Going with the numbers, 35 mpg in and 25 mpg out, and turning the numbers around, it went in using 2.85 gallons per hundred miles and now is using 4 gallons per hundred miles. That's a 40% increase in fuel.

    Just going a bit further, that's like the AFR went from 14.7:1 to 8.9:1. I don't think it would run if like that. So the brakes dragging seems like a plausible explanation and related to the work you'd had done.

    I don't know much about it but wouldn't the calipers and rotors get very hot?

    As for the bike not running after you brought it in and they returned it, I would put my money on a tech in a hurry and cockpit error.

    This will be an interesting one.

  12. #57
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    something that no one mentioned is a plugged catalytic converter or exhaust restriction. You can remove the O2 and use the hole to measure backpressure, it should read almost zero when the engine is revved. The do fail, not often but it happens.

    Rod

  13. #58
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    I haven't opened an oilhead cat to look at construction but have messed with this problem trackside when student vehicles fragged a cat.
    Always they had a ceramic brick sized and positioned in a manner so that when it broke lose it could plug the pipe. Metal mesh types don't do it.
    The fix for the ceramic bricks is simple- grab a piece of rebar and hammer it out...
    Anyone looked inside one of these oilhead cats to see how its made?? Not personally aware of any history of this in oilheads- low probability??

    Brake drag is only one possible cause and it comes in lots of degrees, I've seen psitons gum so bad they froze tyhe bike- in first gear the engine could not overpower the brake freeze. Also send moderate blocks so it was only excessive pad drag- that may or may not generate enough heat to blue a rotor. One could eat 40% more fuel without the more severe examples of brake drag. If at the rear, it might amke enough heat in extreme case to be noticed by touching the FD which normally hits only slightly hot to very warm- 130 or so...

  14. #59
    Registered User rxcrider's Avatar
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    Quote Originally Posted by racer7 View Post
    Failure to use all 6 gears can certainly cause crappy mileage
    I'm willing to bet the OP can't even shift into 6th, let alone use it.

    Humor aside, I rarely run my '95 RS below 3500 RPM and spend a lot of time in 3rd and 4th between 4000 & 7000 rpm. Despite this, I rarely get less than 35 MPG.

    Hope the shop treats you fairly

  15. #60
    Jammess jammess's Avatar
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    Quote Originally Posted by racer7 View Post
    I haven't opened an oilhead cat to look at construction but have messed with this problem trackside when student vehicles fragged a cat.
    Always they had a ceramic brick sized and positioned in a manner so that when it broke lose it could plug the pipe. Metal mesh types don't do it.
    The fix for the ceramic bricks is simple- grab a piece of rebar and hammer it out...
    Anyone looked inside one of these oilhead cats to see how its made?? Not personally aware of any history of this in oilheads- low probability??

    Brake drag is only one possible cause and it comes in lots of degrees, I've seen psitons gum so bad they froze tyhe bike- in first gear the engine could not overpower the brake freeze. Also send moderate blocks so it was only excessive pad drag- that may or may not generate enough heat to blue a rotor. One could eat 40% more fuel without the more severe examples of brake drag. If at the rear, it might amke enough heat in extreme case to be noticed by touching the FD which normally hits only slightly hot to very warm- 130 or so...
    Hello Racer,
    I had the CAT removed from the stock exhaust on my '04 1150RT shortly after purchasing the bike new in '04 and it resembles a bee's nest honey comb and is totally non-restrictive to exhaust flow, you can look right through it. I suppose the passages could become plugged over time but I think that would be a stretch, imo. I also noted no performance improvement just a somewhat throatier sounding exhaust. Cost $50 at a machine shop to have the work done.
    Reason for doing it was at the time I didn't like the heat generated by the CAT so close to the transmission. The shop cut a nice neat square piece out of the top of the CAT chamber then cut out the CAT with a grinder then welded the stainless piece back in place, nice job but probably not worth doing now that I think about it.
    Jammess

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