Correcting Speedometer Errors


Information and questions on GL1200 Goldwings (1984-1987)
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noeleo
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Location: Desha, AR
Motorcycle: 1987 GL1200 A Aspencade Sadly wrecked 2-25-12

1989 Honda GoldWing GL1500

Correcting Speedometer Errors

Post by noeleo »



On my '87 Aspencade, the speedometer works well, but the other day I added a GPS and found the speedometer reading ~5-7 MPH higher than the GPS. Is this something that can be corrected? I thought I read a post heading about this, but now I can't seem to find it. :cry: I know that an error like this will probably not get me a ticket, but I still would like for it to be closer. Thanks in advance for your help.


Ride your GoldWing no faster than your angel can fly.

Gypsy Rover
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Joined: Thu Jun 10, 2010 9:27 am
Location: Edmonton AB Canada
Motorcycle: 1983 GL1100A Aspencade

Re: Correcting Speedometer Errors

Post by Gypsy Rover »

Hi Noeleo, I posted a similar question some weeks ago regarding my 83 Aspey, it was consistently reading high. From the answers I got then it seems to be an endemic fault in all models, perhaps Honda's way of avoiding tickets?

In any event there wasn't any info forthcoming on a fix, just find out how much the error is, with a GPS as you have done and compensate for it. In mine it seems to be linear, off by 4 mph at at all speeds so I just run 5 over the posted limit.

Happy riding
Dale

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WingAdmin
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Re: Correcting Speedometer Errors

Post by WingAdmin »

You can put a slightly larger tire/wheel on the front, which will make it rotate slower, and change the speedometer reading.

Interesting that this is endemic to the 1200's...my 1100 is virtually dead on accurate, matching my GPS speed at all speeds.

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noeleo
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Motorcycle: 1987 GL1200 A Aspencade Sadly wrecked 2-25-12

1989 Honda GoldWing GL1500

Re: Correcting Speedometer Errors

Post by noeleo »

In any event there wasn't any info forthcoming on a fix, just find out how much the error is, with a GPS as you have done and compensate for it. In mine it seems to be linear, off by 4 mph at at all speeds so I just run 5 over the posted limit.
I have found that in my case it is NOT, but logarithmic. At 60 MPH GPS says 54 MPH. AT 70 MPH, GPS says 63 MPH. At 80 MPH, GPS says 72 MPH. Seems more like a percentage-almost like an even 10% versus a continuous 5 or 6 MPH. Wondered about a resistance change in the signal. But then, what about the odometer? Is it off the same 10%? We are taking a trip to Fayetteville, AR for Bikes, Blues, and BBQ this weekend. I will set up the trip meter on the GPS for the trip and see just how much error the odometer has. Will post back after the trip.

Thanks again for the assistance.
Ride your GoldWing no faster than your angel can fly.

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Mooseman
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Re: Correcting Speedometer Errors

Post by Mooseman »

I have noticed on my prior 85A and my 86A that the speedo always read faster than I was going. I think when Honda went to the electronic speedo that the error was put there on purpose for what ever reason. Maybe to make people think they were going faster than they really were. Would be nice if they made a sensor that did the proper read out. I have also noticed that the odometer is off also. SO around town I add about 5mph and at freeway speed I add about 8mph. Seems to be close. I don't have the GPS. Guess I'll have to pull out the stop watch.
Mooseman
Enjoy the ride. They are all good, just some better than others.
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87wing
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Joined: Sun Aug 29, 2010 8:46 am
Location: Palm Bay, FL.
Motorcycle: 1987 GL1200 Aspencade

Re: Correcting Speedometer Errors

Post by 87wing »

I've had this issue on several of my Hondas from the early 80's through 2000, and not just on the wing. I just learn the difference, and compensate as already mentioned.

My 87 is about 4 low at 40, 5 at 60, and 6 at 70 +/- per the GPS.
I just learn that 76 on the highway is really 70.

Roleketu
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Re: Correcting Speedometer Errors

Post by Roleketu »

I've questioned this before also. Found it's a thing of the 1200's. My GPS shows the error is 10%.

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TDarby719
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Location: Clearwater, FL
Motorcycle: 1985 GL1200 LTD

Re: Correcting Speedometer Errors

Post by TDarby719 »

Many other forums and research has shown 10%(+/-) to be the approximate degree of the speed sensor error. Been talked about a lot with people attempting to correct the unit with no positive results. The odometer is obviously affected in the same fashion.

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noeleo
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1989 Honda GoldWing GL1500

Re: Correcting Speedometer Errors

Post by noeleo »

Yes, I, too find the 10% error to be about right. Next question then, could you put on a 10% larger front tire? That would slow down the sensor input to the speedometer, right? :? :? :?
Ride your GoldWing no faster than your angel can fly.

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DaRamblerman
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Motorcycle: 87 GL1200A. 129,600 miles

Re: Correcting Speedometer Errors

Post by DaRamblerman »

Found this. corrects speedo but not odo. It says on their site this is for Honda GL1800A (84-87). I have emailed them for a correction or confirmation but as we know the 1800 was not available in these years. http://shop.12oclocklabs.com/index.php? ... duct_id=59

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DaRamblerman
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Re: Correcting Speedometer Errors

Post by DaRamblerman »


txfireag
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Joined: Sun Jul 14, 2019 3:40 pm
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Motorcycle: 1986 GL1200A Aspencade

Re: Correcting Speedometer Errors

Post by txfireag »

That's a neat find. A little expensive for my taste but the perfectionist in me hates having an "off" speedometer. My Shadow 1100 was the same way.

To clarify, that module doesn't correct the EXIST odometer reading but any additional miles you put on your bike after install will be true miles, not 10% wrong miles.



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