/

7701 Aurora Ave. N., Seattle, WA98103USA

phone: 206-297-3822 fax: 206-297-3828

e-mail:

INSTALLING SPEEDO & TACH CABLES

We’re often asked why these cables break so frequently. For lack of a better answer we like to say that Moto Guzzis are so reliable they had to make one fragile part so dealers would have something to sell. We don’t know the actual fault but have noticed that many cables fail close to the lower end and that they usually appear rusty.

Before going into our suggestions for longer cable life here’s a brief description of how the cable is supposed to work. All inner cables have a brass ring crimped to the top end that keeps it from falling through the outer cable. The lower end of all tach cables and the speedo cables on big twins have a removable end nut that fits into a rubber sleeve plus a barrel-shaped ferrule. The nut and sleeve slip over the outer cable’s lower end, then the ferrule is installed over the protruding bare outer cable. The tapered shape of the nut compresses the ferrule which holds the cable to the engine or transmission. These small pieces do not come attached to the cable and are usually in the same bag with the cable or packaged separately.

Speedo cables for small twins have their own unique end fittings. The lower nut is held in place by a horseshoe-shaped brass clip. Again, the two small pieces may be packaged with the cable or separately.

Our advice for longer cable life consists of the following:

  • Try to keep water out of the cable. The newest lower cable ends have a rubber cap that is longer and seals better. A little silicone sealer between the outer cable and the rubber sleeve might also help keep out water.
  • You may want to grease the entire length of the inner cable. This is fine but keep in mind that the cable usually comes pre-lubed and that too much thick grease can actually cause excessive drag. We suggest coating the bottom end of the combined inner and outer cable in grease before installing it. This will also help keep water away from the cable.
  • Allow a little space between the lower end of the outer cable and the drive receptacle so that heat expansion doesn’t cause a bind. In other words, don’t hold the outer cable tightly into its receptacle while tightening the lower nut. We really don’t know if this will help but it sounds good in theory and is a more convincing fix than telling you to hold your tongue in the right side of your mouth.
  • Since there are no known gremlins in North America that sneak into garages in the dark of night and attempt to pull out speedo and tach cables, we suggest that you only tighten the nut enough to keep the cable from falling out. Any more may constrict the rotating inner cable and lead to an early failure.

One other important point we would like to make: don’t remove the drive worm gear from the engine’s front cover or the transmission unless you really have to in order to dig out an old broken cable. Even then, please make note that there is a small thrust washer on either side of the worm gear. If you do not make sure the lower washer is in position before refitting the worm gear, you may have the washer fall into the workings, so to speak. This has proven especially detrimental on transmissions where the washer can ruin the speedo drive gear and output bearing.

CHS SPED