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Don’t have a clue about what “RPMs” is or why your rev counter (or “tachometer”) has a redline on it?

Then this is the episode for you.

Tune in to discover:

  • What “RPMs” are 
  • Why your motorcycle or scooter has a redline
  • The basics of how a rev limiter works


Hello, and welcome to another episode of 30-minute motorcycling – a podcast for those riders who are at the beginning of their own Dual Wheel Journey, where you’ll discover something new about how your motorcycle, moped, or scooter works – in less than 30 minutes.


Be honest – do you really know what “RPMs” are? Probably not – that’s probably why you’re listening to this episode right now, isn’t it?


Furthermore, perhaps you’ve noticed that your motorcycle or scooter has a dial with a red part or a “redline” if you will near the right end. What’s that all about?


That’s what we’re about to dive deeper into for this episode – we’re going to demystify not only RPMs, but also what the redline is, and why it’s there. 


There’s a lot to cover, so dive right in.


RPMs stands for “Revolutions Per Minute” and refers to how many times the crankshaft (i.e. the thing that converts the linear energy from the engine pistons into rotary energy for the engine) rotates each minute.


Don’t worry – it’s not rocket science – think of RPMs as how fast your engine is working. Because it might surprise you, but while the engine is on, it runs – even if you’re standing completely still.


Because of this, many motorcycles or scooters have a gauge that shows you the engine rotations, and this gauge is called the “tachometer.” 


Sometimes, the tachometer is integrated with the main speedometer – other times, it has its own separate gauge.


While we’re on the topic of the tachometer, let’s talk about the redline.


As I mentioned before, if you look closely at your tachometer, you’ll notice an area on the far right end of the gauge which is colored red. 


This is the “redline” – and the important thing to keep in mind is that your tachometer should stay as far away from this area as possible. 


Why? Because if the engine works at the speeds indicated in the redline, the engine runs REALLY fast – so fast in fact that you might cause irreversible damage to it


If you’d like to know more about the redline, check out the episode description – I’ve put a link there to a brilliant video from RevZilla that goes into further detail. 


So, to summarize, the redline is a no-go area. So how do you avoid it? The best way is to keep the revs as low as possible by selecting the highest possible gear.


To give you extra safety margin, many modern motorcycles are equipped with so-called “rev limiters” that limit the RPMs to avoid causing unnecessary engine wear and tear if you over-rev it either accidentally or deliberately. 


But how do these rev limiters actually work?


If you overrev your engine, the rev limiter steps in and shuts off one of the components that control the combustion process, such as the ignition timing, the spark plugs, or the fuel injectors.


And there you have it – we’ve demystified not only RPMs and the redline – but rev limiters as well. 


If you’d like to read more about the topic, check out the podcast episode description, where I’ve included a link to a blog post on The Dual Wheel Journey about it


Until next time, keep your helmet on and your eyes on the road. Bye!