Hello and welcome to 30 Minute Motorcycling – the podcast where we’re talking two-wheelers – from motorcycles, to scooters, and other things on two wheels – in under 30 minutes.

Do you know what 85cc dirt bikes, large cruisers, and 1000+cc sport bikes have in common? Not much – except one thing – they all use chain drive as their drivetrain.

In fact, did you know that 60% of all motorcycles are chain driven?

Are you also familiar with the phrase “the chain is only as strong as its weakest link?” That applies to the trusty chain-drive too – even it can have problems.

And in this episode, we’re going to talk more in detail about 5 common problems you might encounter with a chain-driven motorcycle. 

The first one is improper chain tension. Chain tension is just like your tire pressure – absolutely crucial.

If the chain is too loose, it will slap around all over the place, and eventually ruin your swingarm. But if it’s too tight, it will strain the bearings, and might even snap. 

And that can spell disaster if it happen when you’re going 100 per hour – whether you measure your speed in kilometers or miles. 

To avoid this, the chain must have enough “chain slack,” to engage and disengage with the front and rear sprockets smoothly.

If you’d like to know more about chain sprockets and chain sizing, please check out episode 49 of 30 Minute Motorcycling. 

And the predictable answer to the question “how much chain slack should I have?” is “it depends on the bike you’ve got” – but as a rough estimate, most street bikes have a chain slack between 20-35mm. Bear in mind though, that is a rough estimate, so remember to check your owner’s manual for more exact specs.

But even if your chain has enough tension, is it lubed up properly?

The chain might be more exposed to the elements than your piston, your crankshaft, or any other moving engine parts – but it’s still part of the engine. 

As such, the chain needs to be lubricated regularly to run smoothly.

Just think about all the rain and mud (especially if you love a bit of off-roading) that your bike soaks up on a regular basis.

All that junk will eventually wear out vital O-ring seals, rollers, and side plates if it stays on your chain for too long.

That’s why lubricating and cleaning your drive chain is one of the most regular parts of regular motorcycle maintenance.

Fortunately, lubricating your drive chain is one of the easiest maintenance jobs to learn.

Also, since it only takes 15 minutes at most, it’s a maintenance job that is as quick as it is easy.

For the third common chain drive issue, I have some bad news for you. No matter how good the chain tension might be and how well-oiled your chain is, there's one inevitable thing.

Over time, chains will start to stretch. It's a slow but steady process, like many other mechanical components.

As your chain wears out, the pitch between the pins and bushes increases, causing sloppy engagement with the sprocket teeth. This accelerates wear even further.

Put it off too long, and it might snap one of these days. 

Excessive chain slack is the most obvious indicator of a worn chain. 

However, a visual inspection revealing cracked seals, stiff links, and discolored metal signifies replacement time.

Measure your chain periodically with a chain wear tool indicator. Please don't wait until it snaps to replace it!

Moving on to the forth common chain drive issue, we have a worn-out sprocket.

But wait a minute – wasn’t this about chains? What do sprockets have to do with chains?

Well, remember, the chain is just one part of the chain drive. Also, do you remember what I said earlier about how “the chain is only as strong as the weakest link?”

In the case of the chain, the sprocket is the weakest link, among other things.

If you've discovered that your chain is worn out, before you replace it, make sure to inspect the rear sprocket, too.

Putting a shiny new chain on a worn sprocket leads to rapid chain stretch and wear, since the teeth will chew through chain side plates.

Damaged and uneven teeth also produce vibration and noise issues.

So how can you tell that your sprocket is worn out? Have you checked your teeth? The teeth on your sprocket, that is.

The most obvious sign that your sprocket needs replacing is the shape of its teeth. If several of them have the shape of a shark fin, it’s time to get a new one.

Apart from that, look for teeth that are either too long or even missing altogether.

Finally, we have the fifth common chain drive issue – the misaligned wheel.

Perhaps it might seem like we’ve wandered off on a completely different topic now, but just like the a worn-out sprocket, having a misaligned wheel might not seem like directly related to issues with the chain.

But it is – remember that the chain wraps around the rear sprocket, which, in turn, is located at the rear wheel.

And a misaligned rear wheel can be a real hidden chain-killer.

The rear sprocket might be fine, but if you’ve got a misaligned wheel, you’ll notice that the chain will start to wear out abnormally.

So what makes it different from the previous one? Well, in this case, the abnormal wear will happen on only one side of the chain.

This is because the sprocket teeth will start to grind down the chain side plates much quicker on the tight side.

And those are the 5 common issues with chain-drive – so remember to tension your chain, lube it up, check the sprockets every now and then, and replace the chain and sprockets when you need to.

Thank you for tuning in, and until next time – happy trails – no matter what or where you ride!