Time To Loosen Your Belt

Nothing will ruin a good time like you’re rubber band breaking half way through your ride. Here are a few tips on maintenance for belts and pulleys.

First off, the rear belt isn’t actually a belt as in fan belt. It is a poly-chain; therefore you tighten it like a chain and not like a fan belt. The specification book calls for about 1/4-inch to 3/8-inch travel with about 10 ft-lbs of upward pressure from the bottom side of the belt. The ft-lb tensioning device also has to be fairly centralized between the front and rear pulleys. I noticed that the new twin-cam FL models have a little gauged window in the bottom belt guard that has notches to make this easy. Each notch is a 1/8-inch increment.

Things that can cause premature wear on belts are over tightening, sand, dirt, rocks etc. You guys that think it looks cool running an open rear belt are in for more headaches down the road, because that guard does a pretty good job of keeping most of the trash out from between the belt and rear pulley. We’ve had a pretty wet year in North Central Texas, and it kind of puts me in mind of a farmhouse I lived in during the early 90’s. It was a very monsoon season and the driveway was dirt. The bike was my only transportation so I rode to work and back in all kinds of weather. I would mud-dog that bike out of the driveway (about the length of 2 football fields) at 5:30 in the morning to head to work.

The point is, that even that stock bottom belt guard would only peel off only so much of that gumbo mud. Some of it got lodged it between my belt and pulleys. At first the mud would mash out evenly so I didn’t notice what was happening, but after the mud got hard-packed in the pulley teeth, some of it flew out, and some of it didn’t. It kind of felt like the tranny was stripping a gear with the back and forth jerking. You get the same sensation when some of the teeth start peeling loose from the inside of the belt, except that is more intermittent.

It was raining hard, so I rode it like that for the 48 miles to work. After work, I spent about 2hrs with a screwdriver digging out hard-packed mud from the teeth of both pulleys. After that, the belt only lasted a few more weeks. Changing the belt involves a helluva lot of work. Ya have to remove the inner and outer primary and either a shock on the drive side, of the centerpiece of the swing arm on softail models. I have it down to just around 4hrs on my ’88 Softail. Eventually I learned that the trick is to keep the back wheel spinning fast enough to keep the mud slung off of the rear wheel.

Another thing poly-chains don’t like is extreme cold weather. Like I said, I had to ride to work in all kinds of weather. It seems the when the temperature reached below 20 degrees Fahrenheit, the belt teeth would tend to get brittle. Then comes that intermittent jerking sensation that I spoke of earlier.

Running your belt too loose will also cause the pulley teeth to wear faster. Most aftermarket pulleys have hard chrome plating over the aluminum, and once that wears off, the softer aluminum wears even faster. All it takes is on piece of gravel getting embedded in the pulley to chip out some of the chrome, and from there, it’s going to progress faster.

Every time you change out your rear tire, you should always inspect the pulleys for wear, along with checking the brake pads and repacking the wheel bearings. Checking the pulleys is easy. First, visually inspect the pulley for anything obvious. Then feel the inside valleys of the teeth to see if a ridge is starting to form on the side where the belt is putting the most pressure on when your riding. If you can feel that it’s starting to wallow out a little, you can either change it out, or keep this in mind and keep a closer eye on it.

Inspect the belt to make sure there isn’t any debris embedded in the belt teeth. This will turn the belt into a kind of grindston