1981 R65 Speedo Question

[flongr65]

Speedo works fine at lower speeds but once you exceed 65MPH or so it begins to bounce all over the place. Odometer works fine. Any ideas on a fix short of sending off to North Hollywood Speedometers? (which I believe runs about $175-$200.)

[larstorders]

Why not replace both speedo and rev counter with an aftermarket digital unit. Save in the long term because sods law states, the tachometer will probably break soon after the speedo has been fixed.
I wish I had considered this alternative before buying a new speedo recently.

[Bob_Roller]

Why don't you try a good cleaning and lubrication of the speedometer drive cable.

Chances are good, that it's never been lubed since it left the factory .

My speedometer needle  was bouncing around until I did this .

I used alcohol as a cleaning agent, and a light air tool oil as the lubricant .

The method I used to clean the drive cable, was to remove the cable from the speedometer, get a heavy grade plastic bag, cut a corner out of it, place the cable into the hole, fold up the bag and place a small ty-wrap around the cable to get a liquid proof seal.

Get a paper clamp type 'paper clip' fold one corner of the bag over, I use a popsicle stick to get a bit of stiffness to the area, and hang it with a piece of string from something overhead in the garage .

Remove the cable from the transmission, chuck the drive cable into a cordless drill.

Fill the plastic bag with a few ounces of alcohol, and turn the drill motor on, with a drip pan underneath, and let the alcohol flow down the cable.

Usually takes 4-5 times to get the cable clean .

Put a few ounces of light oil in the plastic bag, and turn the drill on until the oil comes out the lower end .

[Rob Valdez 79 R65]

And if Bob's suggestion works, I would replace it with a new one, if it were mine.  If it is original (hmmm... a new acronym? IIIO???), anyway, it wouldn't hurt.  And you get a fresh transmission-entry boot in the process.  (they get old & hard and let water in the transmission...)


Myself - I converted to GPS a long time ago.  And I was just looking at that speedo cable that I don't really need, or use, because it so grossly inaccurate, and thinking about removing it, altogether.

To plug the hole, I would need to get one of these made up....





_{photos courtesy of Stephen Bottcher}


Justin???  

[Bob_Roller]

I was considering replacing the speedometer cable, current cost is around $45US .

As far as accuracy is concerned, here in the southeast suburbs of the Phoenix area, we have informational only radar speed signs on the sides of major arterial streets.

Both the airhead , and oilhead speedometers indicate 2 mph high.

There's a mobile speed sign at the entrance to Phoenix Sky Harbor airport, and on weekends, I routinely check the speedometer to the radar indicator, and from 30 mph to 70 mph, both bikes are still reading 2 mph high.

So I know the 85 mph speedometer on the R65, is about as accurate as you're probably going to get with a 29 year old mechanical speedometer .

When I had my odometer repaired in 1998, the shop owner said a dry drive cable will cause needle bouncing, and it will eventually damage the speedometer innards .

Usually the calibrated 'hair' spring that connects to the magnetic drag cup is the first to be damaged .

[flongr65]

Thanks for the suggestions guys. I like to keep the bike fairly original so I'll stick with the speedo and likely buy a new cable. Its surely original and the boot is dried out as well.

Thanks, Frank

[Bob_Roller]

You can get the rubber boot, without buying an entire cable assembly .

[Justin B.]

Rob, shouldn't be a problem...  Although I'd probably leave off the nipple (maybe glue on a roundel)  and stick with a ventilated retaining bolt like this one...

[Rob Valdez 79 R65]

Rob, shouldn't be a problem...  Although I'd probably leave off the nipple (maybe glue on a roundel)  and stick with a ventilated retaining bolt like this one...

I hadn't thought of that.  Stephen did that for his river crossings!

I suppose I could get by with a standard vent/fastener.  
That is a pretty one you have there.  I assume you have part of a box of them on the shelf?  

I'm going to relocate my ground wire while I am putting the bike back together.  
Grounding the diode board, too...

[Justin B.]

I keep a couple made up, too lazy to churn out a box of 'em!  

[Ed Miller]

I would like something like that.  I can't remember what Monte (was it, with the Vapor?  Sorry if I'm mixing people up.) did for that area.  

[Rob Valdez 79 R65]

I keep a couple made up, too lazy to churn out a box of 'em!  

So you modified a store-bought fastener.
That makes sense.
I'm happy with the one I have, in that case.

[montmil]

Yep. It be Monte with the Vapor digital. So much info stored insuch a small package. No mechanical drive cables, either. I plugged the speedo drive hole with a tapered, rubber bung plug. Tighter'n a tick.

[flongr65]

When your rplacing the speedo cable how do you remove the end that goes into the transmission?

[Bob_Roller]

The bolt that secures the negative battery cable to the transmission, also holds the speedometer drive cable to the transmission .

Completely remove the bolt, and then pull the cable out, a black plastic bushing will also probably come out with the cable .

When you get the bolt out, check to see if you can see through a small hole drilled through it, this hole is the vent for the transmission .