I have a 1998 FLHTC-I.

This past fall my presumably stock speedometer cable and drive unit failed each other with the odometer at about 75k.

Long story short i work at the parts department of my local dealership and our service team does most of my repairs and replaced the cable with an OEM H-D replacement but since H-D no longer offers an OEM drive unit we have been using aftermarket ones and i have now broken my 5th aftermarket drive unit (3 from Drag, 2 from Custom Chrome) along with my original one.

With the cable attached to the drive unit but unattached to the speedometer the drive unit seems to spin freely without problem, but as soon as you hook it up to the speedometer and hand spin the wheel the tension binds the drive unit up and it ultimately fails when driven with the tab bending, slipping out of the rotor slot and wedging into the drive unit body destroying the gear inside...

We have tested the speedometer and are completely out of ideas.

Tomorrow i will be ordering one from V-Twin as they are the only company left that offer a replacement drive unit.

I do not want to replace the transmission for one with a sensor so i have been tossing around 2 ideas.

The first being a Dakota Digital Gauge swap but the Mechanical Speedometer Cable Adaptor uses a drive unit so we would have to adapt the Rear Wheel Speed Sensor or the Universal Inductive Speed Sensor but that option is clearly not cost effective.

The second idea is to remove the drive unit completely, replace it with a proper spacer and install a self canceling turn signal module but that option is perilous.

Currently there are 3 OEM salvaged drive units on eBay which i am also contemplating picking up.

I cannot locate any NOS units and my dealer network is completely dry.

Any help is appreciated, Thanks!

 

Dude you seriously need to go back and put paragraphs in that mess!!!!
One big block of text is very hard to follow!!!!

 

I went through the same issue when I had the wrong speedo drive for the specific wheel I had

 

Is the Cable binding when you hook it to speedometer maybe? Have you tried Hooking cable to speedo and either twisting drive end with finger first and if free maybe hook a drill to it and see if it binds?

 

Try re-routing the cable differently through the frame members.

Try not tightening down the ends to tightly.

Make sure there is grease in the housing, make sure the housing (for the drive cable) has a smooth bore. You didn't specify if you replaced the cable and housing besides the drive unit on the wheel.

Make sure the width of the drive unit matches the old unit, after all it is part of the spacer pack for the front wheel.

 

Sounds like the drive unit it not the correct one for the speedometer. There are different ratio drives.
http://www.jpcycles.com/1998-harley-...dometer-drives

 

26699: Speedo drive unit for FLHT 1996-98. Replaces Harley 67101-96 (OEM: 51-006)

 

When you are putting the new drive unit on, make sure that the tab that fits into the rotor is not longer than the rotor is wide. If the front wheel is torqued and the tab is too long, it will bend back. You may have to trim the tab a bit to make sure that everything stays nice and square when the front wheel is torqed

 

You've got something else going on there. It's not the drive unit causing the problems. What is the length of the cable?

 

Just replaced the speedo drive unit and cable on my 1984 FLHTC. It's tricky to put in with all the chrome covers this scoot has (disc brake covers, caliper covers). Here's what I learned in doing this.
1. snug the axle nut and spin the wheel to ensure the tab from the drive is engaged in the slot. Sounds easy, but if not centered the drive is ruined the 1st time you ride.
2. proper axle nut torque - 55 ft-lbs is important. Don't over tighten.
3. Greasing your new cable is fine....but don't use heavy grease. I did and the thing howled like a pig stuck under a fence. After cleaning and using lithium grease, it is now quiet.
4. Since the cable housing has to screw into the speedo drive unit, mount the other end on the speedo, leave it slightly loose, route the cable and install the other end, then tighten the speedo end and install the instrument panel. Don't screw the cable housing into the drive unit too tight.