Advice required R1100RT speedo not working

[Ian]

Speedo sitting at zero when riding. Please advise on procedure to check whether sensor or gauge problem?

 

Ian

[BigArn]

It's cable driven. Check for a broken cable.

[John Dickens]

They seem to break about 6" away from the front wheel connection.

They are easy to change. You can do it without removing any of the bodywork. Just leave the old one connected at the top as a guide till you feed the new one up there.

[OoPEZoO]

You need to figure out what broke.....its usually either the cable or the pickup on the front wheel. Its a simple cable system. You can disconnect it from the under side of the speedo (unscrews by hand or pliers), and from the wheel pickup on the clutch side of the front wheel (one phillips head screw).

 

You can also pull the cable from the front wheel pickup and then attach it to a power drill to make sure that speedo still works.

 

I had the pickup on mine fail after about 65k miles. I disconnected the cable from the speedo and spun the front wheel, but the cable wouldn't spin. Then I reconnected it to the speedo and disconnected the cable from the pickup. Then spun the front wheel again. I could see the pickup spinning inside the hub, so I assumed I had a broken cable. After a little more investigation I figured out that the pickup would spin until there was some resistance applied. Then it would stop. Turns out they have a nylon worm gear inside the pickup, and mine had stripped out.

[Ken H.]

It's also not unusual for the cable to simply vibrate loose from the back of the speedo. Check the easy stuff first!

[Steve_Witmer]

Concur you should check cable first. They seem to get dry inside eventually and will fail thereafter. It's not only an easy repair, but by BMW standards it's cheap.

 

If it's not the cable, but this thread makes you think about lubing yours while you are working on the issue, exercise restraint with the lubricant. You don't want any working its way into the speedometer head nor do you want any dripping out the lower end after it gets warm.

[flars]

Here's what I posted over on the RS forum:

Sorry if this sounds pedantic, but here is the basic troubleshooting stuff:

1. The cable could have come loose from the back of the speedometer (not unusual). You can get your hand up in there to see it the knurled knob is still screwed onto the back of the speedo. Re-attaching it can often be done in situ (i.e. without removing any fairing parts) if you can get a pair of pliers up in there, but sometimes you have to remove the speedo/tacho unit to reattach them...depends on how big your hands are.

2. The inner cable could have broken (common). Remove the screw that holds the cable to the back of the speedo drive down at the front wheel, pull the cable sheath off the hub, and pull the inner cable out. If you have two pieces of inner cable, or if it ain't long enuff it's broke. Buy a new speedo cable. (I am pretty sure you can't buy just the inner cable anywhere so you will have to get a new cable assembly from BMW, but what do I know?)

3. The drive dogs in the speedo hub down at the front wheel could be eaten up. With the bike on the center stand, remove the screw that holds the cable to the speedo hub. The speedo cable is driven by a little blade sticking out of the hub. Spin the front wheel, and watch the little blade spin around. If the blade spins, grab it with a pair of needle nose pliers and slowly spin the wheel to make sure it REALLY wants to spin. Sometimes it will spin with no load, but won't if it meets with any resistance. If it isn't spinning under both these conditions, the problem is in that speedo drive mechanism.

 

Part II - the speedo hub.

Pull the front axle out of the front wheel (you don't need to roll the wheel away so you don't need to pull the calipers or anything - just get the axle out). The speedo hub will fall off into the dirt. Left inside the wheel behind a grease seal will be a drive dog (looks like a big washer, with two teeth sticking out) The grease seal just pushes into the wheel hub. Pull it out (I use a paint can opener to hook it out with). The drive dog will be laying right there - take it out, it's not held in in any way. It should have two ears sticking out radially, and two sticking out vertically. The radial ears engage two notches in the wheel, and the vertical ears engage the speedo hub. On my bike, the two radial ears had been eaten completely off. Costs 80 cents to replace. Put a little grease inside the speedo hub to lubricate the worm gear. Put the bike back together...done.

If the radial drive dog ears are still there, look at the speedo hub. Pull the plastic insert out of the hub. The two vertical ears on the drive dog engage those little plastic ears that stick out of that plastic piece. The drive dog ears sometimes (as in always) get bent slightly so they don't engage the plastic ears completely. You will probably see a little damage to the plastic where the metal ears have spun inside the plastic ears. If this is the case, and the plastic isn't too badly chewed up, bend the drive dog ears out slightly so they engage the plastic ears more completely. Put a little grease inside the speedo hub to lubricate the worm gear. Put the bike back together.

If the plastic is really eaten up, you can add a little contact area for the ears with JB Weld. Clean the plastic piece thoroughly with brake or electrical contact cleaner and use JB Weld and a file to beef the plastic contact area up. Put a little grease inside the speedo hub to lubricate the worm gear. Put the bike back together.

If you don't believe in JB Weld, buy a new speedo hub (the plastic piece is not available seperately). Put a little grease inside the speedo hub to lubricate the worm gear. Put the bike back together.

Ride.

[Mark K]

It's also not unusual for the cable to simply vibrate loose from the back of the speedo. Check the easy stuff first!

 

Happened to me twice!

[John Montoya]

Mine came loose from the back of the speedo as well. I went ahead and pulled mine out, cleaned and lubed it. Also when you take the front wheel off you need to look at the drive gear, it may need greasing.

[Charles Elms]

Quote:

It's also not unusual for the cable to simply vibrate loose from the back of the speedo. Check the easy stuff first!

 

 

 

Happened to me twice!

Me too.

Also had to replace cable later. Easy job if you have small hands. If large hands you might have to keep re-attaching cable to back of speedo on regular basis until you can get a pair of pliars up there to tighten it.

[Clive Liddell]

1. I would not lube the cable since all the cable sheaths seem to have the teflon? inner and thus why would the speedo cable be different?

 

2. Someone years ago someone wrote here that RT riders should try and avoid a sharp left angle of the steering because is does give the lower section of cable quite a sharp bend. I have, ever since then, only locked my steering to the RH side. No cable problems (yet).

[Steve_Witmer]

Unlike the control cables which slide relatively slowly and for brief periods of time, the inner shaft of the speedo cable spins at a fairly good speed whenever the bike is in motion. It is a lubricated cable, and very similar in design to the extension cable on a Dremel rotary tool. If it is unlubricated it will rapidly fail because of excessive heat generated during operation.