For the most part, control cable woes are a result of dirt/water intrusion, failed lubrication, and/or improper routing. Take care of these three things and your control cables will provide a long life of effort-free service. Problem is, few riders pay any attention to their control cables until the actuation effort becomes unbearable or the cable snaps.

A control cable is an assembly of simple parts, basically consisting of a cable housing and inner cable core. The housing is made from a flat spring steel coil wound to form a flexible tube. Some OEM and aftermarket cable manufactures line the inside of the housing with a Teflon or nylon inner liner that greatly reduces friction and lubrication requirements. All cable housings have a plastic outer sheath or skin that insulates the cable core from dirt and water. The cable core itself is a piece of multi-strand wire rope with soldered-on ends. Two types of control cable ends are common, a barrel type end, typically used for levers or external clutch actuation arms, and a bullet type end.

Clutch cable cores are inherently more heavy duty (read: girthier) than control cables used for throttle actuation. Some OEM cables (e.g., KTM) and aftermarket offerings from Motion Pro use a trick two-piece swiveling barrel end which contributes to significantly better cable life by reducing stresses and associated failures due to unlubricated barrel sockets seizing in the lever. These are comprised of a bullet type cable end used in conjunction with a floating barrel (read: a barrel end drilled to accept the bullet cable end). Some OEM Japanese cables use a similar approach, a nylon bushing that fits around the barrel to improve barrel lubrication, although this is not nearly effective as the swiveling barrel. The reason to dwell on this is that, surprisingly, most cable failures are due to lack of lubrication at the lever (or throttle actuator) rather than problems with the cable itself. It turns out that even a shiny new cable will fail in quick order if the barrel end is insufficiently lubricated and not able to rotate within the lever. This results in an uneven pull on the barrel end that quickly fatigues the cable strands where they enter the barrel, forcing a premature failure. The swiveling barrel counteracts this effect by allowing the cable bullet end to rotate within the barrel, as well as the barrel within the lever, thus reducing angular stresses and eliminating this hazard.

Maintenance

Cable maintenance is a three part drill; essentially cleaning, lubrication and repair. Nearly all maintenance is most easily accomplished with the cable removed from the bike. This allows a more complete inspection of the cable and allows gravity to work for you during cleaning and lubrication efforts. Obviously, the cable exterior is best kept as clean as possible, facilitating identification of any nicks or burrs in the cable outer sheath. We mentioned control cable repair, and while there’s not much that can be done with a broken cable core, the plastic sheath that covers the cable housing should be checked regularly for nicks, cuts and abrasion and repaired as necessary. Repairs may be made using electrical tape or, better yet, shrink tubing. The object here is to retain a water and dirt proof barrier on the cable housing to prevent future damage to the cable core.

Once removed from the bike, the cable core should easily slide within the cable housing. If the cable binds in any way then solvent must be used in order to break things free. To accomplish this, there are several approaches. The cable could be submerged in a pan of kerosene or diesel fuel for several days, while alternately working the cable core in the housing. Similarly, an aerosol type spray solvent/lubricant like WD40 or CRC could be used in conjunction with a cable lubing tool (manufactured by Motion Pro, Terry Cable, et. al., and available from your dealer). These trick little devices fit onto the end of a cable to be lubed/cleaned and permit spraying of aerosol driven solvents/lubes directly into the cable housing with no muss or fuss. Another approach is to fashion a "funnel" around one end of the cable housing, pour in solvent and allow it to "drain" through the cable housing. The effectiveness of all of each these methods is enhanced by physically working the cable core through the housing so as to dislodge accumulated crud and work it out the end of the cable housing. Holding the cable vertical helps here too. Some cables, like the OEM Husky cables on our ‘85 WR and perhaps some aftermarket offerings, actually come with lubrication ports built right into the cable housing. This greatly eases application of solvents/lubricants and does away with the need for specific cable lubrication tools.

Once things are clean and the cable core moves smoothly through the cable housing, its time to take actions to keep them that way. Depending upon the solvent used for cleaning, a flushing with brake cleaner or carb cleaner might be in order prior to lubrication. Certainly any hydrocarbon solvents (read: kerosene or diesel fuel) must be flushed, otherwise they’ll break down your fresh lubricant. Regarding lubricants, several options exist here as well, each of which offer their own particular benefits and drawbacks.

Surprisingly, the first option is none at all. Many mechanics feel that any and all lubricants attract and hold dirt, thus causing more harm than good. This is especially true of cables manufactured with Teflon or nylon inner inserts, as the slippery nature of those inner liners really need no additional lube. If you’re starting with a fresh new cable that’s never been lubed, this is perhaps a worthy option.

When using a cable that has no inner liner, then continued lubrication will be necessary. Many of the aerosol products used for cleaning (e.g., WD40, et. al.) also lubricate just fine. Silicon based spray-on lubricants are also effective (as a lubricant), and like other aerosol cleaners and lubricants, are most easily applied by holding the cable vertically and using your cable lubrication tool, spraying lube into one end until it drips out the other. While we personally prefer the aforementioned aerosol type lubricants, some mechanics stick with more traditional oil-based lubes, which might actually have a longer staying power once applied. The drawback here is that left unattended for long periods they tend to attract more dirt than the silicon based aerosol lubricants and can leave hard deposits as they aerate. If this is your preference, a light weight machine oil (like 2.5 wt.) works best and pours easily enough so that its not too difficult to get into the cable housing. As a practical application, those couple of ounces of suspension fluid left over after your last fork oil change will do the trick as well. We’ve seen a syringe type oil pump with a thin needle outlet, small enough to fit down inside the cable housing, that’s the trick setup for applying liquid cable lubricants. We mentioned earlier that some cable housings have integral lubrication fittings, which help getting liquid lubes into the housing and might also accept the end of a grease gun, permitting lubrication with bearing grease. While grease is fine for wheels, linkage, etc., we’d generally recommend against using it for control cables on dirt mounts. Where a dab of grease is really needed though, is in the clutch lever socket that accepts your clutch cable barrel end. Lubrication of this pivot point is the most important thing you can do to extend the life of your cables. While you’re at it, you might as well clean and lube the lever base pivot and cable adjuster nuts as well. When buttoning things up, be sure to reinstall or replace rubber cable end/lever boots used at the various cable ends or lever pivots. These go a long way in the battle to keep dirt and water out. Zip or wire tie boot and cable ends where they enter your throttle housing, carburetor, etc. to further seal things up. Finally, pay close attention to cable routing when reinstalling the cable onto the frame. Generally speaking, avoid sharp bends, binding and beware of cables becoming pinched as the steering head is turned or when reinstalling other hardware (e.g., radiators). If you really want to be sure, model specific OEM factory cable routing is often illustrated in your shop or owners manual. However, this really shouldn’t be necessary as common sense rules. Once completed, adjust your cable free-play and rotate your handlebars lock to lock, checking for proper control operation without any hitches or hanging up. With that, fire her up and hit the trail.