Hello all,
Been working on my '85 K100RT, getting my odometer up and running. Thanks to this forum and the wealth of knowledge contained here, I disassembled my instrument cluster and discovered the gears were missing teeth (the three which usually break - 12T motor gear, 16/44 drive gear, and 28/40 drive gear). After a few web and forum searches, I found a couple of really helpful sites, which I wanted to pass along:

hampspeedometer.com - Hamp's is located north of Atlanta. I spoke with "Hamp" himself. Very knowledgeable and helpful. Fast shipping, but cost me a bit more.

speedometergears.com - a bit less expensive and takes PayPal Don't know much about this site, but you can purchase gears individually.

Hope this helps!

Now, I'm looking for an o-ring gasket to reassemble my gauges. Anybody have a source in the states?

Thanks for the tip on speedo gear sources. Here's the part number for the instrument cluster O-ring, 62 11 1 459 232 and it's only about $6.86 at a US dealer. Cheap enough to throw 'em a bone, eh.

Thanks for the tip on the gears supplier. (I hope that I will not have to use them).

CF

Two Wheels Better wrote:Thanks for the tip on speedo gear sources. Here's the part number for the instrument cluster O-ring, 62 11 1 459 232 and it's only about $6.86 at a US dealer. Cheap enough to throw 'em a bone, eh.

Yes, definitely, if only I had a dealer in Alabama! I'll have to contact the dealer in Atlanta, or find one in Florida. Thanks very much!

Tks kg4miq, I have same problem. Can you explain to me, when you say 12T motor gear, 16/44 drive gear and 28/40 drive gear is that referring to the teeth number and diameter? my smallest gear is completely stripped so I have no idea how many teeth or diameter it was and I am hoping to order them without dismantling my speedo first (again)
Tks RT

I have used that second site for an older BMW 528 that I restored. I would recommend them (speedometergears.com). kg, can you modify the hotlink to also show the website name?

RT, just be aware that the tooth count will be different for miles and kilometers. I think the speedometergears site may be able to tell you which one you need, he was able to do that for me on the 528.

The numbers simply refer to the quantity of teeth on the gear. Almost all gear-driven odometers have a 12T primary (the small gear which is completely stripped). DO NOT try and completely remove the brass bushing from the motor shaft...simply clean the old plastic material from the bushing. When you get the new 12-tooth gear, if necessary, ream the inside of it with a small reamer or drill bit until it fits snugly on the shaft. Per "Hamp" himself, at Hamp's speedo repair, most of the difficulties are with people attempting a repair and damaging the motor trying to get the brass bushing off the shaft. It ends up pulling the shaft from the motor end.

As for the 16/44 and 28/40, these are the two colored gears (mine are orange and green), which have a gear on each side - the 44-tooth gear is the obverse, the 16-tooth gear is the reverse. Likewise with the 28T/40T. You can see a photo in the second link above. (I would have ordered set #10-062 for my bike...yours may be different.)

As for the diameter, this is determined solely by the larger number of teeth a gear has.

These gears are not unique to BMW motorcycles, and therefore, they are still current for many models of automobile and motorcyle. However, the sizing is critical. I'm having to return a gear because they sent the incorrect one (22/40). You'll need to make certain you get the correct combination for your speedo (year, make, and model - e.g. KPH vs. MPH).

Hope this helps!

Excellent info, I can approach my local supplier sounding at least
edumacated a bit.Thanks for the tip club_c, I just naturally assume klm .
One more thing to add to the list of "to do's"
Cheers RT

TWB, called BMW Motorcycles of Atlanta in Mariettta and ordered the instrument cluster gasket today. $5.72, shipped to my house! Nice! Thanks for the part number!

No worries, mate. That's what we're here for.

Got everything reassembled this evening and took 'er out for a spin! Works flawlessly. Put on about 24 miles. Many thanks to all for the help! Now, if I can just find that thread about calibrating the speedo...

Don't know if you have found it and I can't find it now but Bert (our resident crazy frog) came up with a small program to use on the computer to calibrate the speedo. The idea is that you plug the speaker outlet on the computer into the speedo just under the right battery cover and it sends out pulses that replicate the pulses from the pickup. It can be set at 30 50 60 Kph right up to 240kph but you can convert to mph. I dare say some one will come along and find it in a flash for you. I haven't used it yet but what a great idea.

Aye, Karamba!

Downloaded the program and I understand the principle behind calibrating the speedo, but I don't know if I recall seeing the calibration adjustment pot in the instrument cluster the other day. Does anyone happen to have a picture of it?

kg4miq, have a look here.

There is a link to a photo showing you where the adjustment pot is.

Thanks very much! That's exactly the information I need. Now, back to disassembling the instrument cluster...

I've grown tired of having a fully functioning speedo but inactive odometer. I must have put on an additional 35000 kms over the past eighteen months with my daily travels, the trip to Victoria, up to Cape York, and last year's Long Ride Round OZ. So, I've got my speedometer apart on the bench in front of me right now and have stripped it down to the essentials.

Using a strong magnifying glass I was able to spot part numbers and teeth count on the back of each cog. I've verified the teeth count by marking them, and I've taken pictures of the disassembly through the various stages and will post them with descriptions when I reassemble the cluster.

This is the tooth count and gear colour for Km/h speedo heads:

(My 'bike is a 1986 K100RS, and this might differ for yours.)

Part number 236 is white with 11/33 teeth (The pink colour has blended onto this cog from the other one)
Part number 237 is pink with 23 teeth
Part number 238 is brown/orange with 34/40 teeth (this is the one that's totally stuffed)
Part number 239 is red/orange with 16/44 teeth
The primary gear is brown with 12 teeth

(Warning, I am mildly colour blind, as most blokes are!)



The 34/40 tooth cog is stripped of half its teeth and the rest of the cogs are in good nick. Fragments of the teeth were spread throughout the cluster. The bits had jammed the odometer completely. Once cleaned out the cluster spun freely.

It turns out the recently discovered Redcliffe, Queensland seller (by the name of Parts Lunacy on eBay) DOES NOT have any Motometer gear sets for BMW motorbikes. I am now hot on the trail of the nearest seller who does supply them in Australia. Ray Peake BMW repair of Canungra has the set but he's two hours away by road, and a tad expensive. I might have to mail order them from him if my rock-turning-over session turns up nothing locally. I'll keep ya's posted. Cheers!

Update: I'm taking a spin down to Otto's in Salisbury (on the southside of Brissy) tomorrow. I rang him and although he was reluctant to sell the gears separately (says he only repairs the units) he agreed that if I was in that far he'd let me have 'em. Bonus.

Here's another US site in Virginia with some useful information:

http://www.odometergears.com/products/BMW/R+%26+K+Motorcycles/42

Click the link then select the drop-down at the bottom of the page for replacement single gears. I hope this helps someone. Cheers!

You are a champion, that is exactly the info I need mate. Now I can put this job on my ever expanding to do list.
Cheers RT

All in a day's work, RT! No worries. Cheers!

One more thing I forgot to mention earlier...Hamp said the three gears which usually break are the 12T motor gear and the two dual-tooth drive gears closest to the motor (MM1, MM2 in the link to the site in Virginia). He said the other two (P/N 236 and 237 respectively, in your post above, TWB) rarely ever break, since they're normally made of a different material. I think that's why the replacement sets usually only come with 3 or 4 gears, rather than an entire set of 5.

I've just picked up two cogs from Otto's in Salisbury, south of Brisbane. The 34/40 tooth (AU$33.00) is now black and the 12T primary (AU$16.50) on the motor shaft is now red. I'd thought I didn't need a new one until he showed me how they crumble under pressure like NSW at the State of Origin. The other three are as new and he reckons two of them had been replaced at some stage. John was helpful and offered me some tips on reassembly, warned me not to use any sort of lube, and told me what to use to free up the number rollers if they're binding, which he says is often what 'eats' these gears prematurely - that is contact cleaner in small blasts, then allow it to 'dry' or dissipate. Now to reassemble the mess and set the speedo using aye, Karamba!



Talk to John @
Lionel Otto Instruments
124 Evans Road
Salisbury Queensland 4107

07 3277 3888 phone
07 3277 8520 fax

Update: The odometer now ticks over like an old straight-six Chevrolet. Everything else works too. It's my first time using the Deoxit cleaner and Gold sealant and the multi pins came up shiny and like-new on the back of the cluster. I'm gunna celebrate with a cherry in my ginger ale... Yes! Good stuff.

Good info in this thread! Thanks for all the contributions! Sticky, maybe?

Question on these speedos, the RT speedo will run fine and then drop off slowly, or not so slowly sometimes. I tap the housing and it comes back to life. Electrical contacts need cleaning (not done yet) or gears dying. BTW, odo stops when speedo stops.

Mine had been doing this as well. Deoxit the dual connectors at the back, and while you're at it, have a go on the easily accessible connectors under the seat and behind the side covers too. It works wonders. The plastic & rubber gears are only for the trip and mileage odometres. When the gears go, they lose their teeth (which often takes out another gear that otherwise would have been OK), and the odo quits altogether or you get a hop to their rotation up until they quit altogether.

nods head ....speedo sensor connector joins up there ...look for the funny greenish colour on the one at the side cover ......grin

but also check for tight loom to connector cables at the instrument cluster.


good work on the gears twb ......yay!!!!

well got my speedo tore down and sure enough I had chewed up gears 12 is gone totally found peices everywhere lost 28/40 and 16/44 will be ordering a new set found a couple things i didnt like the 3 pin connector bracket was broke in two and i have one pin on the main connection thats loose its the bottom right pin not sure what it runs but have a feeling its my first warning light for low fuel as that was the only light I had that dont work I know could be the bulb since the second low fuel light works. and the brass peice is still on the motor shaft im going to file it down till it is to the shaft should make removal easy

Just a thought if DeoxIT is going to be used on something plastic like the odometer drum consider getting their aerosol version which is rated plastic safe it is a bit more expensive than the standard but does the contact cleaning bit just as well. I just bought two cans the G and the S in the plastic safe version specifically to go over the speedo again.
Regards,
K-BIKE