The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Biocruiser on April 29, 2008, 11:16:41 AM

Title: speedo failure
Post by: Biocruiser on April 29, 2008, 11:16:41 AM

I was out for a nice sunday drive and... the speedo quit. Before I start tearing things apart I was wondering if there's a common failure point for the speedo assembly. I check the connections on the cable and they seem to be good and tight. Can the instrument itself fail? It went from fully functional to nada while riding...

Title: Re: speedo failure
Post by: Bob_Roller on April 29, 2008, 11:51:01 AM

I think this the first I've heard of a speedometer failing, usually it's the odometer part that fails.

There's not much to a speedometer, the cable turns a shaft with a small magnet attached to it, that rotates inside of a cup assembly, and a small 'hairspring' attaches to the shaft coming off of the cup that the needle is attached to.

If something is broke in there, there are no replacement parts available, except to remove parts from a 'donor' speedometer.

Make sure the drive cable is turning at the speedometer end, outside chance the cable has problems.

Title: Re: speedo failure
Post by: Justin B. on April 29, 2008, 12:59:18 PM

All of the instances in which I have experienced a total speed failure were caused by a broken cable.  Usually it is preceded with a "jerky" needle.

Title: Re: speedo failure
Post by: crazy_dan on April 29, 2008, 01:10:08 PM

mine did that too...got really jumpy and then dropped down to nothing.  initially i thought it was the cable, but one of the gears inside the speedo froze up and took out the drive unit down in the tranny in the end.  hopefully you don't have the same problem, it's not a cheap fix (unless you can find the stuff on ebay).

good luck

Title: Re: speedo failure
Post by: Justin B. on April 29, 2008, 03:06:09 PM

Ouch, never had that happen!  :o

Title: Re: speedo failure
Post by: Biocruiser on April 29, 2008, 05:05:21 PM

Hmm... didn't notice a "jerky" needle, but I did notice that the ODO wasn't functioning a few weeks back. I hit the reset a few times and it came back to life. I'm going to take a ride with the cable disconnected at the gage and see if it spins. Hopefully It won't!

Title: Re: speedo failure
Post by: Biocruiser on April 29, 2008, 05:12:53 PM

Just went around the block... cable no spinny. Hopefully that's all it is...

Title: Re: speedo failure
Post by: Bob_Roller on April 29, 2008, 05:45:22 PM

Speedometer drive cables are one of those often forgotten parts that need to be lubricated every once in a while.

Title: Re: speedo failure
Post by: Justin B. on April 29, 2008, 07:59:40 PM

Hmmm, I'be never lubed them as I always figgered they had a teflon/nylon/something no-lube liner like the other cables.  Maybe that's why I've had a couple go bad on me

Title: Re: speedo failure
Post by: Bob_Roller on April 29, 2008, 08:06:51 PM

I started using a light oil, like air tool oil, I clean it with running alcohol through the cable, then blow it out with compressed air, 80,000 miles, and still the original cable, and no erratic speedometer needle movement either.

Title: Re: speedo failure
Post by: Justin B. on April 29, 2008, 09:57:07 PM

I'll have to keep that in mind.  This thread has turned out better than I'd hoped when I just glamced at the subject.  I'm glad that speedo turned out to be the mechanical variety...  :P

Title: Re: speedo failure
Post by: Biocruiser on April 30, 2008, 06:43:59 PM

It was the cable...