Topic: 2 speedometers buggered in less than 6 months, what gives?

[manjisann]

I have a 1980 cb650 custom. The original speedometer that came with the bike would bounce so badly that you couldn't tell the speed you were traveling at. I bought a replacement off of ebay and it has worked for a thousand or so miles over the course of 3 or 4 months. I took a 150 mile trip yesterday and on the way back the gauge face cracked up near the odometer, and I started to hear a funny whirring noise that I believe to have been the speedometer cable and the speedometer needle is bouncing badly as well as not telling the speed I am traveling at. I greased the cable with white lithium grease last night, which is what i used the last time it started making this whirring noise. The cable is routed correctly, there's no sharp bends in it or anything and I'm fairly certain the part where it connects into the back of the speedometer isn't rounded out. The cable is a motion pro cable which isn't as long as the stock cable, could this somehow be causing the problem?

So my question is, what on earth am I doing wrong? Why would the gauges face plate crack, and why is the needle suddenly bouncing like an overcaffeinated child on a pogo stick? I'd just buy a replacement, but I don't really want to buy a new gauge every 4 months.

Thoughts?

Thanks,

Brandon

[cb650]

You must just be lucky.   Cant say I've ever had a problem with a 650 speedo.  Sounds like you have everything covered.

[manjisann]

I'm thinking of just replacing it and buying an OEM cable and see if that fixes the issue.

Brandon

[Don R]

I think someone posted a similar deal before and it was the drive gear at the wheel. Maybe a search would turn it up.

[Slams77]

Just a thought but it could be that when the forks extended (uneven pavement) the cable retracts in the housing causing it to temporarily disengage from the speedometer or even the speedometer gear.  Does it happen more on bumpy roads instead of smooth roads, or is it happening all the time?

[manjisann]

Slams77, that's a good thought but doesn't appear to be the case.

DonR I did do a search, which brought me to where I am now.

So as DonR suggested, I did do a search. I actually did it prior to posting this, but was confused by the fact I had 2 buggered speedometers in less than 6 months. The search turned up only a couple of articles, but one of them suggested pouring Denatured Alcohol into the speedometer, swirling it around and dumping it out. Sounds simple enough, and the execution was simple, but the end result was one step forward, and a step back sorta. The Alcohol got rid of the jumpyness, the needle is pretty smooth now with at most a 5mph bounce. The step back is what it did to the gauge face, the paint has ran so badly now that it's very hard to see the numbers.

Brandon