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wrong speedo e(a)ffects KMs?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by tonee, Oct 9, 2010.

  1. Gday,

    My speedo displayers higher than I'm actually going, and someone has told me it will clock up the kms faster than it actually is too. Can someone please confirm.

    Thanks
    Tony


     
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  2. Makes logical sense to me. Also makes you believe your getting better fuel consumption than you really are.
     
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  3. Sounds good to me
     
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  4. My clock is fast and sometimes I get to where I'm going before I leave home.

    Its not uncommon for bike speedo's to be 5% - 8% optimistic but the odo's seem to me much more accurate. It all helps with the pissing contest at the pub so dont sweat.
     
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  5. Think I read somewhere that speedo's are made to over read while odo's are set quite accurately. Having said that, I know the odo on our mirage overreads by about 25m pre kilometre, but that could just be tyre diameter variation
     
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  6. Unless it's all electronic, speedos that have a mechanical odometer should be fairly accurate, based on correct tyre, gearing and so on. In cable driven speedos it's a direct relationship. Whereas, with the speedo itself, it's a meter that's driven electrically or via spinning magnets to drag the needle around against a spring.

    You'd think that one, like say on the later model Blackbirds, which are totally electronic, would be accurate. But no, they're not. One of the favorite mods is a gadget called a "Speedo Healer" which when installed, allows you to correct the signal going to the speedo and when calibrated against a GPS, for example, will give an accurate speedo.

    Me, I'd rather spend $40 on a cycle computer than $200 on a Speedo Healer. Does the same job (gives you a spot on speedo) and a mini-trip computer into the bargain.
     
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  7. a bicycle speedo on a motorbike, now there's an idea
     
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  8. Sometimes, on these forums, it's difficult to tell whether someone's being a smartarse, ignorant or genuine...
     
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  9. From personal experience, the triumph street triple (so it applies to the daytona too), have the speedo overread programmed into the ECU so that it reads around 6.5% over. The odometer is very accurate (I have checked and confirmed this). I suspect this is the case with most late model bikes these days.

    I have also installed a speedo-healer as I want to know -exactly- what speed I'm doing.
     
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  10. Depends on why the speedo is reading wrong. If it's because the chain sprockets (or wheels, tyres) have been changed, then it will affect the odo.
    If it's because the speedo unit itself is calibrated inaccurately it probably won't. Odos usually have a separate system but use the same info coming in.
     
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  11. Most bikes are set up with a reasonably accurate odometer and a speedo that overreads 5-10%. Its counter-intuitive, but the fact that the speedo is wrong doesn't mean the odo will be. Both will be affected by changes in tyre rolling radius and may be affected by sprocket size changes, depending on whether the speedo drive comes from the gearbox or the front wheel.
     
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  12. Very soon after I got my gs500f, I new there was something wrong with the speedo reading.
    Did a few tests to see what was going on like got my wife to sit on speed limits on different roads and attached a gps and I now know that my correct speed is 10% less than my speedo is indicating.

    Then did tests on the odo.
    Marked out 1K using the car and my bicycle (it's speedo is calibrated and accurate) and found the the odo on the gs is perfect.
    Also on the way to Sydney, there are places where they have marks on side of road where you can test your distances.
    Once again odo was perfect.

    I believe the over indicating speedo is set diliberately like that from the manufacturers for whatever reason.

    Oh by the way, putting bicycle computers on motorcycles is a common practice which I've seen many times by riders who know there's something wrong with their speedos.

    Although I use the speed on the gps most of the time, I would really prefer speedos to be correct in the first place.
     
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  13. It's an in-built 'hero' factor. It helps stop people from getting speeding tickets and also gives them a large margin of error because speedos can't legally UNDER read.
     
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  14. Got a small speedo issue
    My stock gearing on sprokets is front 15 rear 44. I was after more of a touring oriented setup to lower the revs at higher speeds so changed the rear to 42 and have a 16 front which I have yet to put on. The reduction of 2 teeth has obviously effected the speedo. To compensate for this I had also ordered a speedo healer along with the sprockets from overseas to compensate the offset and correct the speedo.

    I bought below speedodrd calibrator
    http://www.sprocketcenter.com/p/1119299/speedodrd-speedometer-calibrator---honda.html
    The problem we came across was the attachment on the calibrator didn't match the one on my bike. Have been in talk with 12 oclock labs who is the manufacturer of the calibrator and they want photos of the attachment on my bike which is meant to connect to the unit. I have sent them photos but they want more detailed photos which will require pretty much stripping things down which will cost time and money. Just spoke to my mechanic and he said he will try and change either end to make it match. The healer has an old attachment compared to my bike.
    IMG_0162.
    IMG_0163.

    Any suggestions?
     
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  15. You can check it easy enough. I know there's plenty of places near me where they mark out 5kms on a freeway for motorists to check there odometers. If you can't find one of these just use google maps to measure a journey and see if it matches what your bike says.
     
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  16. Get the right plugs & modify the speedo healer, leave the bikes plugs alone, that way you can remove it if you need to.

    If you're not worried about removing it in the future, just splice it into the wiring loom.
     
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  17. I have done that already a few times as well as asking somebody in a car/bike to cruise at 100km/h while I ride beside them to gauge the offset. It's not accurate. Speedos are not accurate to begin with for various reasons but now mine is a bit off which is why I don't want to change the gearing on the front sprocket as yet as that will further offset it so I would like to get the healer put on it.
    Hmm where would I get the right plugs from? Agree on the rest.
     
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  18. Oh and also the most cost effective way to fix a speedo is with a bright coloured permanent marker. Work out what speed = what and mark it infront of your spedometer. Not the prettiest way but cheap as chips and you can wash it off with some alcohol if you want something a little less cheap looking.

    And Resmen, I was talking about checking the odometer not the speedo.
     
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  19. Haven't tried checking the odometer it's an idea but if I was to check against other variables I wouldn't have bought the healer that's why I'm looking at ways of implementing the healer on to the bike despite the connectors not matching.
     
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  20. Bursons, Repco, etc, but it may a proprietary plug from Honda...

    Actually, you could replace the plugs on your bike & the speedo healer with some good Narva ones, that way you could still remove the healer if necessary, but you're bike plugs would be different to OEM...

    Not recommended, but it may be your only option if the plugs are proprietary.
     
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