Is your motorcycle engine running hot? Hotter than usual? Hotter as in “lots-of-smoke-seeping-out-from-the-engine-block” hot? Then you might have an engine overheating problem. But what are some common reasons why this happens – and what can you do about them? In this blog post, you’ll discover:
  • Typical motorcycle overheating symptoms – both for air-cooled and liquid-cooled engines
  • How to solve the problem of an engine overheating
Prefer to get this information in podcast form? Listen to the 30 Minute Motorcycling Podcast episode about the 5 most common overheating problems for air-cooled and liquid-cooled engines:

Need a refresher on the differences between air-cooled vs. liquid-cooled engines? Check out the blog post about it here on the Dual Wheel Journey.

Liquid-cooled engines overheating – 4 common reasons

1. Low coolant level

image of coolant
Remember – the coolant is what cools down your engine and prevents it from overheating. Therefore, if the coolant level for your bike is too low, the problem is easy to fix. All you have to do is refill your topping up your coolant, and you’re good to go. 

2. A leak in the cooling system

image of coolant spill

Seen any puddles or drips underneath your motorcycle, and you’re positive it’s not oil?

Then there might be a leak somewhere in your cooling system.

But it’s also possible that the end of a hose isn’t attached correctly. It might even be possible that the leak is coming straight from the radiator.

Either way, check the coolant hoses and the radiator for leaks and repair them if needed.

3. Clogged coolant passages

This is similar to the point above, except, in this case, the problem isn’t a coolant leak. Instead, the problem is that the coolant won’t circulate properly due to a blockage in the system.  To solve this problem, first, flush the entire coolant system and refill it with a new coolant.

4. A faulty water pump

image of water pump
The water pump is responsible for pumping the coolant around. Therefore, if the water pump doesn’t work, the coolant isn’t going anywhere – it will just stay inside the reservoir. The best solution is to remove, inspect, and, if needed, replace the water pump.  

Air-Cooled Engines Overheating – 2 Common Reasons

One advantage of an air-cooled engine is that it doesn’t rely on coolant to cool down the engine. Therefore, you don’t have to worry about leaks, blockages, or even the fact that the coolant level is too low. But with that in mind, an air-cooled engine can still overheat

1. Blocked cooling vents

Mangan 2002, CC BY-SA 3.0, via Wikimedia Commons
Since the air needed to cool the engine enters via the cooling vents, no air can enter the engine if said vents are blocked. And as a result, the engine won’t be cooled down.  Try to clean the cooling vents out and adjust the engine cowling (i.e., the removable metal cover part of the engine) if you have to.  

2. A broken cooling fan

Some air-cooled engines rely on an engine-assisted fan to provide consistently cold air – known as “forced air-cooling.” The only problem is that if that fan should stop working, there’s no (or at the very least insufficient) engine cooling. Check the cooling fan’s fuse if you suspect you have a broken engine fanIf the fuse is broken, replace it. But if the fuse is working like it’s supposed to, there might be a problem with the fan motor. If that’s the case, you’ll need to renew the entire cooling fan.