speedometer reading off?

[airportcop]

I have a 1980 GS 550L and have replaced the speedo cable with a new one but it seems that it reads 10 MPH slow. Any ideas? Thanks.


Kevin

[duaneage]

Oversized Front tire?

How about spraying a little silicone spray into the speedometer and see if that clears it up.

[IanFrancisco]

Usually these speedos are off the other way. Indicated 60mph = actual 55mph or so. It would take a MUCH larger front tire or incorrect parts in the speedo drive in the front hub to cause the error you're getting. I second the lube suggestion but don't do what I did, which was to use chain wax on the old XL175 speedo. Steadied up the needle which had a pronounced oscillation before but would cause the needle to stick at 0mph when the bike sat a while. Took a healthy slap to free it up until I used contact cleaner with silicone. That did the trick but be sure to use stuff that is safe on plastic.

[duaneage]

The silicone spray leaves a dry lubrication that cleans parts well. WD-40 has solvents that attack some plastics and wash the grease away from the gears for the odometer, causing trouble there.

Do you have the correct speedo drive on the bike? are there any part numbers on it? I understand that most japanese bies use a standard ratio of 2.6 - 1. I can check this with my spare this weekend and let you know.