Odometer / speedometer jump: 5k extra miles!

[qwerty123]

Hi all,

Long time member, frequent lurker here.

I recently did some beginning-of-season service on my '84 R65 (changed oil + filter, flushed brake fluid, etc.). I note work I've done in the manual, and I noted a mileage of 49,XXX miles when doing that.

About 50 miles into a weekend trip, I noticed the odo was reading 55,XXX! I reset the trip odo and watched. It counts up, but very slowly. It seems like it's not successfully rolling over the last digit, FWIW.

I'm thinking maybe some cable was functioning like a spring and had a bunch of twist in it, which let go all at once?

Speedo seems to be working fine, although noticeably optimistic (I read this is common) and it wavers a tiny bit at higher speeds. Little rubber hat on reset button is gone (has been for maybe 6 mo.); the bike is stored under a cover outside. It's on my list....

Does anyone in the group have any thoughts as to what could be causing this and how it might be addressed? Background reading suggests fixes are difficult but possible, and many people send them to professionals.

Thanks much,

Matt, near Boston

[montmil]

Worn plastic gears in the odo. Perhaps. Not an uncommon occurance. Rebuild would correct the issue but at a pricey cost.

[Bob_Roller]

No parts are available to repair a speedometer if a part is worn out, usually you need a donor speedometer to rob parts from .

I believe one of our members here, repairs speedometers, I think it's wilcom .

[wilcom]

Re: Odometer / speedometer jump: 5k extra miles!
Reply #2 - Today at 17:46:56 Alert Board Moderator about this Post! Mark & Quote Quote


I believe one of our members here, repairs speedometers, I think it's wilcom  

NOT ME......"Wirespokes" is the fellow and I hear is has a trusted following

[Bob_Roller]

My mistake !!!!

[wilcom]

My mistake !!!! Shocked

I'd like it to be me, but I just checked and I don't have any hammers labeled "SPEDO"

[Bob_Roller]

I was close, the name started with a W !!

[Tony Smith]

You can make your own new gears, all you need is the outside diameter, a blank gear with the right spindle hole(able to be purchased from model car racing places), the number of teeth needed, a small vice, steady hands and patience.

lets say you need 20 teeth, that means that there will be a tooth every  360/20 = 18 degrees. or 90/18 =  5.

So mark off a 90 degree segment on your gear blank and then divide that arc visually into 5 equal segments.  If you are uncomfortable with 5 segments you could  try a 45 degree arc 45/18= 2.5 teeth, but htis then creates the problem of carrying the remainder.


Remember that pinpoint accuracy is not needed for an odometer, if you have the right number of teeth and it meshes reasonably well with its mate, it will be OK.

[Tony Smith]

Further to my last

Here are some people who will make the gear for you (and approach it a little more scientifically than i did.

http://makezine.com/2010/06/28/make-your-own-gears/


and another diy method

http://www.wikihow.com/Make-Metal-Gears-With-Minimal-Hardware

[montmil]

Re: Odometer / speedometer jump: 5k extra miles!
Reply #2 - Today at 17:46:56 Alert Board Moderator about this Post! Mark & Quote Quote


I believe one of our members here, repairs speedometers, I think it's wilcom  

NOT ME......"Wirespokes" is the fellow and I hear is has a trusted following

I also once referred speedo repairs to Joe, aka Wilcom "Don't call me Wirespokes".
I see financial opportunities... [ch129297]

[wilcom]

I see financial opportunities.

Once my first repair came back to you and the bezel looked like it was opened up with a P-38 I'd probably be in court LOL

[Warbucks]

The odometer has smashed gears and it's possible that your speedo cable caused the damage. The trip meter on my bike was suffering from the same problem that yours has. If the issue is not addressed, it won't be long before the odometer will start displaying ludicrous speed. Shortly after that you will witness the death of the instrument. It is still repairable at that point. You can still use your tachometer to determine your speed until the odometer is repaired. As an example, in 5th gear at 3250 RPM my speed is 70 kph (43.5 mph).

The chances are that all of the gears will need replacing. If one gear is completely smashed, it is likely that there are others that are not too far behind it. You can try to repair the odometer yourself as Tony has suggested; or you could part with a considerable amount of cash to have it rebuilt. I recently did the latter and it cost $250.00 AUD. I'm not concerned about the price because it shouldn't be an issue for many years to come.

When you get the odometer working correctly and calibrated, it would be advisable to purchase and fit a brand new cable. I bought an aftermarket cable from England which cost another $50.00 AUD. Apparently the rubber seal which stops moisture from entering at the reset button is no longer available for a 1985 model. I assume the same applies to earlier models.

[qwerty123]

Well just wanted to close the loop here guys.

The problem ended up being exactly the problem described here:
https://secure2.pbase.com/dwerbil/1978_r1007_odometer_repair
(click on each picture and look at the subtitles for procedure).

There's a small gray cast gear on the same shaft as the odo numbers (visible in the photos attached) that starts slipping on its shaft. Degreased the shaft as best I could, and a drop of CA seems to have secured it. All the gears appear to be in excellent shape. I've added a dab of grease here and there, and it's a good opportunity to replace the failed little rubber hat over the trip reset button, too.

Thanks again for all the help!

Matt