Well, that didn't work...

It lasted about 3/10 of a mile...

I dont understand. I can't pinpoint a speed, a direction, etc. It just seems to break randomly.

What else could cause this? A bad/too long key? A weak key? A bad speedo? Something internal? Those electric speedos keep sounding better and better...

 

If you're using the correct #3280165 key,the adapter spins freely,not wobbly internally,then the only things left are the cable and the speedo housing itself. The cable is 16 bucks,the price of two keys.If that doesn't solve it,then the Vapor is starting to look good on this old 22 year old machine..

 

Can you elaborate on "wobbly internally?" I'm not exactly sure what you're referring to or how to check this...

I think I'll go ahead and order a couple more keys and a cable regardless, but yeah, a digital speedo keeps sounding better and better...

(On that note, are there any newer fuel tanks that have sending units in them that will interchange??? Wishful thinking obviously, but what's the worst you can say, "No?")

 

When you spin the adapter at the end going to the speedo slowly does the insert that holds the key turns straight,not loose and wobbles.This can break keys also. They can wear out over the years.Just one thing to make sure of. Just try it with a new cable and key. If it breaks it again then something in the speedo housing may be at fault.

 

I had an older 350L that had an issue similar to yours. I couldn't keep a key in it and the head unit (speedometer) turned freely with out jumping if I spun it at the speedometer itself but if I spun it with the cable attached the needle was a little erratic. I took the cable completely off and sprayed it with wd 40 and it seemed to turn smooth. The casing of the cable was fine also. I found an oem cable and replaced it and my problem went away. When I pulled the old cable apart, it had a bad spot in the core that was rusty and a little frayed. My assumption was that it would turn fine by hand or drill but once installed the cable had enough pressure on it to cause it to bind when the cable turned and heated up.

good luck,
Mike