motorcycle speedometer manipulation

Discussion in 'The Projects Forum' started by Farlander, Aug 29, 2011.

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  1. Farlander

    Thread Starter Active Member

    Oct 14, 2008
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    Ok, I got a ticket going 98 in a 65 on my motorcycle. I am going to have my speedometer calibrated, but I'm pretty sure it will be found to be accurate, because whenever I pass those slow down reminders, the speeds match.
    I found out I have an electric speed sensor, and I want to know if I can insert an extra capacitor or resistor that will affect the way the speedometer interprets the signal from the speed sensor. The sensor itself is mounted to the front chain sprocket where it somehow detects rotational speed and there are three wires which connect it to the gauge. Attached is a diagram from the service manual instructing how to test the sensor after removing it from the bike. It says that once you hook this up, you can brush a screw driver across the sensor and see 12V spikes. Can somebody please help me understand how this works so I can keep myself out of jail? All I need is to get it down below 30mph over for my state to not lock me up. Thank you...
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    It's what is called a "Hall-effect" sensor. It detects the proximity (or lack thereof) of ferrous metal objects.

    If you tamper with the signal, you'll cause your speedo to malfunction.

    You need to have your speedo serviced ASAP by a certified shop. It'll be cheaper than a ticket, and far, far cheaper than a funeral.

    Other than that, we can't discuss modifications of automotive electrical stuff on the Forums; they're on the "prohibited" list. Have a look in our Terms of Service, paragraph 6.
     
  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    No resistor or capacitor will help you. The speedo makes a pulse for each revolution, then some other device counts them per second to tell the speed. If you want to keep out of jail, next time stay below the limits or go racing on a track.
     
  4. debe

    Well-Known Member

    Sep 21, 2010
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    Here in Australia there is a kit avalable that alters the timing of the sender pulses to the speedo it is wired betwean the sender & the speedo. It then is adjusted using a GPS to get the speedo acurate. Have built one for a guy that fitted a different dif ratio to his vehicle.
     
    Last edited: Aug 29, 2011
  5. Kermit2

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    Feb 5, 2010
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    My understanding is that JAIL is not usual in a case of a first offense. Have you been ticketed for high speeds before? and did you not learn of the possibility that more extreme punishments would be handed down without heeding the warnings given by the first incident?
     
  6. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Just stop being a hotdog and slow down. Your speedo is accurate. You might want to get your head calibrated though. :)
     
  7. Farlander

    Thread Starter Active Member

    Oct 14, 2008
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    Thank you Sgt. I am aware of the hall effect...

    Without going into detail on any actual speedometer manipulation, could somebody explain how the "healer" kits or "tuners"which alter the frequency of the pulses work? Could I build one? I need this done asap and a tuner box for my machine is $100 + shipping delay.
     
  8. strantor

    AAC Fanatic!

    Oct 3, 2010
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    So, you think your speedometer is fine, but you want to change the readout anyways? Fooling yourself into thinking you are going slower than you really are, won't fool the cops into thinking you are going slower than you really are. sounds like you need to play with the governor more than you need to play with the speedometer.
     
  9. kubeek

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    These tuners are basicly microcontrollers which measure the input frequency and produce altered waveform.
     
  10. kubeek

    AAC Fanatic!

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    Christ, he needs to alter the speedo so he can say it was malfunctioning and not go to jail. You and Sgt. should try reading more carefully ;)
     
  11. Farlander

    Thread Starter Active Member

    Oct 14, 2008
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    Thank you Kubeek. I had also deduced that these were some kind of microcontrollers that I would not be able to readily build so I went ahead and ordered one. Hopefully it will arrive and leave me enough time to get down to a speed shop and have the speedometer "verified". And yes if this works I will hopefully stay out of jail, this is the most legitimate way I have found to "calibrate" a motorcycle speedometer, but I should also mention that the speed I was really going was in the triple digits - I had altered it in the initial post so as to protect my identity. And yes they will lock you up for that. Not much help from the moralists but they kept the post active. Thanks for the fast replies.
     
  12. mcgyvr

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    Oct 15, 2009
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    Grow up and take your punishment like a man. Maybe a little jail time will keep you from getting killed in the future.. Or maybe not.

    This post should be locked/deleted for idiots helping an idiot commit fraud.
     
  13. t06afre

    AAC Fanatic!

    May 11, 2009
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    I think we can apply the no auto modification rule on this one.
     
  14. wayneh

    Expert

    Sep 9, 2010
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    Let him hack it. When the authorities detect that attempt at perjury, it'll be an even bigger penalty and we'll get this lame-brain off the road.
     
  15. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Doh! yeah I missed that. That may be stupid on my part, but there's something a whole lot stupider going on here.
     
  16. Farlander

    Thread Starter Active Member

    Oct 14, 2008
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    I'm glad there are so many of you do-gooders out there who have never actually gone to a detention facility and cannot possibly understand what I'm going through.

    Also, I'm glad so many people are hypocritical enough to lecture me on maturity, posting irrelevant comments with no value relative to the topic.

    Besides, idiots have rights too.
     
  17. strantor

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    Far from it. Been there, done that, paid the price. Never went to jail but I should have. When I was a teen I got into lots of pickles like this. got a ticket for going 96 in a 55. one for 85 in a 40. and several lesser tickets. Also crashed into a house trying to race in the rain with bald tires. That was the one that sent the message home; when I nearly killed an elderly couple who were inside watching TV. I was pretty big idiot back then, and in some a lot of ways I still am.

    Idiots do have rights; just like the innocent people potentially affected by their idiot actions.
     
  18. strantor

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    My advice, one idiot to another would be to take the punishment. when you try to cover things up, you're taking a risk bigger than the first risk; get caught and things will be so much worse for you.
     
  19. mcgyvr

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    A lecture on your lack of maturity is exactly what is needed here.

    Want some relative "value filled" information.. Ok. Grow up, get a lawyer, go to court, put on a nice tie and shirt, arrive on time, and beg for mercy. If this is your first penalty you will likely get a fine/license suspension instead of "detention". But attempting fraud to try to fight your obvious speeding ticket is asinine. Police officers and judges aren't stupid and have been around the block way more times that you.. You don't think anyone else has tried to play the "my speedo is out of calibration" trick before. It won't fly and you could even be adding multiple charges to your case.. Plus, No speedo calibration shop in their right mind is going to sign off on your speedo BS knowing you are attempting to trick them too. Then they are committing fraud too.
     
  20. SgtWookie

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    Jul 17, 2007
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    I'm not going to lecture you.

    However, if you can determine how many pulses your Hall-effect sensor puts out per revolution of the wheel, and what the radius or outside diameter of your tire is, we could figure out a way to determine what your actual speedometer linearity is with a fairly simple bit of circuitry.
     
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