GL1500 Speedo shows very high inaccurate readings


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riderken61@gmail.com
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GL1500 Speedo shows very high inaccurate readings

Post by riderken61@gmail.com »



Today on the way home from a friends house I looked down at my speedo and it was buried fully while I was driving at normal highway speed and as I slowed down on the ramp the speedo slowly dropped to zero.. so when I started up again and was driving at 70 km/hr (40 mph) the speedo showed 160 and 180 kmh (100 mph). Are not these mechanical? How can this be happening, what can be the cause and how do I fix it? Thanks in advance.


Last edited by riderken61@gmail.com on Sun Oct 16, 2022 6:04 pm, edited 1 time in total.
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Rambozo
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Re: GL1500 Speedo shows very high inaccurate readings

Post by Rambozo »

Speedo needs service. Dried lube inside can cause issues like that.
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Re: GL1500 Speedo shows very high inaccurate readings

Post by riderken61@gmail.com »

I can see how a needed service could slow down the cable and cause slower indicated readings than actual speed but it seems odd it would cause bizarrely high readings…. Is the needle gear driven or is there an electronic interface between where the speedo cable entered the device and the needle’s movements?
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Re: GL1500 Speedo shows very high inaccurate readings

Post by Rambozo »

Typically there is a spinning disc with a magnet or a drag clutch that mates with the part that drives the needle. These two have a controlled slip. If debris or sticky oil gets between them they don't slip as much so the needle reads high. If it gets bad enough it will destroy the speedo as the needle will start spinning around and rip out the springs and stops and such. So if you can't fix it right away, disconnect the speedometer cable to protect it until you can.
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Re: GL1500 Speedo shows very high inaccurate readings

Post by riderken61@gmail.com »

Thanks for the explanation of that. Will disconnect for now and see what’s what this winter.

Is the unit serviceable, should I plan on removing the speedometer and somehow taking it apart to clean?
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Re: GL1500 Speedo shows very high inaccurate readings

Post by Rambozo »

Unless you've done it before or are fine with replacing it if things go wrong, have at it. It's much like watch repair, in that too much oil is as bad as not enough. Now that everything is electronic, speedo shops are few and far between, so you may not have many options. The hairspring is the part to be careful with.
Someone here just was able to get theirs working without taking everything apart, by using a spray cleaner and lube. You will still have to at least remove it from the dash.
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Re: GL1500 Speedo shows very high inaccurate readings

Post by offcenter »

There is al good speedometer repair place in California that I used for my CT-90 speedo. They were good. The speedo came back looking and working like new.
Maybe someone here can remember the name and location of the place.
George in Jersey.
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Re: GL1500 Speedo shows very high inaccurate readings

Post by Limpy45 »

If you have ever had a older automobile speedometer head apart it is quite easy. Of course it may take some careful tinkering to get it exact again. I timed my 99 1500 over measured mile posts and then calculated actual speed and compared that to indicated plus GPS speed. Mine was reading about 4 mph fast at 60 actual and very close to that percentage all across the speed. I had done some on my cars over the years and so was prepared to tinker to get it very close to exact. Also cleaned and lubed it lightly while apart. I did remove the speedo head from the instrument panel so it was easier to work on. Now it indicates very close to my GPS unit.
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Re: GL1500 Speedo shows very high inaccurate readings

Post by riderken61@gmail.com »

I have been thinking about this and also the excellent info and responses from you all so far…. When I did the front wheel bearings and rebuilt the calipers etc etc Ai serviced the Speedo drive at the front wheel…. I cleaned it thoroughly but did pack a whack of grease into it….

Would too much grease in the Speedo drive at the hub possibly work it’s way un the cable and into the actual Speedo unit?

Anyway I found a rebuild place in Canada as one option but an assessment costs a minimum of $150….

Whereas I found a used unit with 90,000 miles on it on ebay for around $120 including shipping…. So I got a decision to make…. Would just have to take a photo of the old Speedo and the new at the changeover and calculate the tru mileage when I sell the bike in a few years….
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Re: GL1500 Speedo shows very high inaccurate readings

Post by Rambozo »

Not likely you could get grease up the cable unless you greased it everyday for a month or so.
You have a third option. Just take apart the speedo you have and see if anything obvious is wrong. You can still send it out for repair, or replace it if you can't figure it out. You can run it on the bench with a drill to see how it works.
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Re: GL1500 Speedo shows very high inaccurate readings

Post by Swagonmaster »

While this won't really help here because the speedo is running very fast, as Rambozo said, if you use an electric drill (the speed is predictable and consistent) and a short length of old speedo cable you can run the speedo (remember, counterclockwise!) to see what speed is shown before taking the unit apart. That makes calibration a lot easier since you have a benchmark to set it to. In this case, it might be interesting to turn the speedo backwards to see if that would free up the drive mechanism and that could be done down at the wheel without taking everything apart. If that manages to free up the drive mechanism then you can decide if you want to disassemble the head to clean it properly.


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