Speedo is WAY off

[Guest]

I found a replacement speedo for my "G" model to replace the damaged original. Looks great and the odometer is accurate but the speedo at an indicated 75 mph is only doing an actual 63, almost 15% error. Anybody had any luck adjusting these. I have seen threads regarding different ideas on how to get into the instrument but nothing on fixing the innards.

[cowboyup3371]

Basscliff's site has a link about cleaning them up. I'm unable to connect to his page right now but it's in your welcome package he gave you awhile back

[bbjumper]

I'm lookin for it, thanks

[cowboyup3371]

Actually it's not on his site. Do a search on repair speedo and you'll get a few threads about it.

[chuck hahn]

And just how did you determine this?? Know any cops..have them radar you at a few different speeds to see what the gun says. Or maybe a school pitching coach with a gun??

[sedelen]

I know the speedometer in the GS1000E's are way off. It was mentioned in several of the test reports when the bike made it's debut. I once topped out my skunk with an "indicated" 140, but more than likely I probably wasn't even going 130. One of the tests gave the amount of the error but I can't remember what it was, but the indicated speed was pretty optimistic.
So, how can you correct it? The only way I know is a larger diameter front tire.

[trevor]

Speedo error must have been common back in the day. I have a test from an 80 mag. that compares a kz750 a cb750 and a gs750 in they say the speedo speed indicated against radar and all 3 bikes were out at least a few mph at 60mph. And they always did these tests on other bikes too. My question is if the speedo is not right how can the miles indicater be right? My guess is is a bike that has 56 or 57000 mi on it is really closer to 60000mi.

[sedelen]

Speedo error must have been common back in the day. I have a test from an 80 mag. that compares a kz750 a cb750 and a gs750 in they say the speedo speed indicated against radar and all 3 bikes were out at least a few mph at 60mph. And they always did these tests on other bikes too. My question is if the speedo is not right how can the miles indicater be right? My guess is is a bike that has 56 or 57000 mi on it is really closer to 60000mi.

On my 1000's the speed indicated is higher, I don't know if that would effect the odometers accuracy since the outputs (speed, distance) are indicated in two different places, most likely with different physical gearing, but if those ratios are the same, it would have the same effect, and I would think that your 57K indicated would be less instead of more.

[bbjumper]

And just how did you determine this?? Know any cops..have them radar you at a few different speeds to see what the gun says. Or maybe a school pitching coach with a gun??

I carried my GPS on the tank bag to verify speed and have done several trips to my GF house, which by the way is exactly 31.4 miles door to door, she's geographically challenged but we won't go there.

[hampshirehog]

The speed readout is governed by the magnet and I don't think there is anything you can do to adjust this other than make the magnet stronger (or in your case weaker) using another magnet - and that would be pot luck doing it at home. The mileometer is a direct drive so that should stay accurate.

Have you checked the error at lower speeds? You could try moving the needle round by the 15mph and you would be accurate at 63 but when you are doing 20 you might only be showing 5.

[rustybronco]

In addition to what HH said, changing the tension on the hairspring or, the friction on the needle dampener should effect a change in the indicated speed. but that would require one to do a bit of surgery on the speedo.

**this is what the tach mechanism looks like when taken apart. it should give you some idea what I'm taking about.

http://thegsresources.com/_forum/attachment.php?attachmentid=15439&d=1327023783

***the dampener is the silver cylinder to the right of the hair spring.

****considering the OP's speedo has a needle rest (pin), you might want to try and lift the needle over the pin, note it's resting position then remove the needle and replace it in a position slightly anti-clockwise.

[bbjumper]

Have you checked the error at lower speeds? You could try moving the needle round by the 15mph and you would be accurate at 63 but when you are doing 20 you might only be showing 5.[/QUOTE]

Yes, I have checked, at an indicated 40 I'm doing about 35, so its not linear. I am sure this speedo spent decades on a shelf somewhere and may be suffering from lack of lubrication. Would excess friction cause it to indicate fast? I can live with it the way it is and judge my speed via the tach but it's always in my face and begging to be fixed. Thanks Guys

[rustybronco]

I am sure this speedo spent decades on a shelf somewhere and may be suffering from lack of lubrication. Would excess friction cause it to indicate fast?

Excessive friction should make it read lower.

[hampshirehog]

Excessive friction should make it read lower.

And very often you will be doing 20-50, 20-50, 20-50 as the needle wobbles about.

[rustybronco]

Other than a damaged drive cable, another thing that may cause the needle to oscillate, is a worn needle dampener.