What to do: When your drive belt snaps

Prevention, symptoms, and replacement

With the growing number of riders now, many of whom are on automatic scooters, a growing concern is the lifespan of the drive belt. Having your drive belt snap on you is possibly one of the most frustrating things that can possibly happen. It instantly disables your motorcycle and is difficult to repair on the roadside. When this happens, you're left with little recourse but to leave your bike or walk it to the nearest shop.

Drive belt failure is a relatively rare occurrence. After all, these belts are meant to last tens of thousands of kilometers. 

Thankfully, if you pay enough attention, there are many ways to tell if your belt drive is about to fail.

Regular Inspection

The best way to prevent this is with regular inspection. Your motorcycle's owner's manual will have details on how often to replace the belt, and what size belt to replace it with. The belt is usually checked with regular service intervals at your motorcycle service center.

Some brands recommend changing the drive belt every 2 years, or every 10,000 kilometers or so, some every 20,000 kilometers, while others can be as long as 100,000 kilometers.

If you are doing your own maintenance, it's best to at least have a look at the belt every time you change the engine's oil. Simply prop up the bike on the center stand (or side stand) and unscrew the bolts to remove the transmission cover. From here, you'll be able to see the condition of the belt.

Symptoms

Worn belts will sometimes slip. This is pretty easy to detect as the way the motorcycle accelerates won't be in sync with your throttle.

Another good indicator is a noticeable loss in power, or a lower top speed. Worn belts tend to sink deeper into the pulleys, effectively changing your gear ratios and reducing the power transmitted.

Sometimes however, it can suddenly snap with little warning. This can happen in particularly dusty or debris-filled environments. It can also happen if the belt replacement is overdue. Finally, there are rare occurrences when rocks or other debris can penetrate the transmission housing and damage the belt.

Symptoms on the belt

First, rotate the rear pulley and check the inside and outside surfaces, looking for cracks, missing teeth, tears, or holes on the belt itself. A few hairline cracks, nicks in teeth, or minor fraying along the edges is normal and nothing to worry about.

Check for more serious damage like sidewall wear (tears in the top corner), wear on the top outside surface, long deep cracks along the length or width, or missing teeth. These are signs of more serious problems. Schedule a session with your preferred service center to replace the belt and diagnose the problem.

Next, take a look at the pulleys. If they’re chromed, make sure that the material isn’t flaking. These can damage the belt, and also could be a sign of temperature or wear problems.

Another good indicator is the transmission casing itself. Rubbing marks on these surfaces may indicate that the belt has lost tension and is hitting the edges of the transmission casing on some occasions.

Finally, use a ruler to measure the width of the belt. The owner's manual will tell you how wide it should be when new, and how wide it should be when it's time to replace it.

Replacing a belt

If a belt has already snapped on you, then your best bet is to walk the bike to the nearest repair shop and have them replace the belt for you. We do recommend bringing a spare with you (in the correct manufacturer specified size) to make it easier for any nearby shop to replace.

It is possible to replace the belt yourself if you have the right tools with you and a replacement belt. However, this is not something easily done on the roadside. It requires large and specialist tools, involves some disassembly, and may need the help of another person. Even after replacing the belt, other tools are needed to check its deflection, and if it is seated properly in the pulleys. This is a repair job we recommend you leave to the experts.

Instead, it might be a better idea to keep the number of a towing service or a friend with a pickup handy. This will make it easier to recover your bike and bring it to your trusted repair shop if the inevitable belt snap does happen.