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Apologies if this is a naive question, but:

I am a new rider, just got my bike a few months ago. While reading the manual, I noticed it says "Never declutch while braking at higher speeds".

English is not my native language, and so I just wanted to clearly understand what it means. Is it saying that while braking, I should NOT press the clutch? Is this related to letting engine braking aid you while braking?

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  • Welcome to Motor Vehicle Maintenance & Repair! Commented Jul 12, 2021 at 18:58
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    The word "declutch" means to RELEASE the clutch so that the engine is again connected to the transmission.
    – jwh20
    Commented Jul 12, 2021 at 19:38
  • @jwh20 and what does “double declutch” mean?
    – Solar Mike
    Commented Jul 12, 2021 at 19:43
  • @jwh20 so i should never allow the engine to connect to the wheels when braking? The answer from alephzero seems to indicate the opposite...
    – Somjit
    Commented Jul 12, 2021 at 20:05
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    @jwh20 all the dictionary definitions state the opposite of what you said.
    – HandyHowie
    Commented Jul 12, 2021 at 20:40

3 Answers 3

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There are two things to think about here.

(1) On a bike, engine braking only acts on the back wheel. If you press the clutch while you are braking hard, you change the "balance" of the braking force between the front and back wheels, which might cause problems especially if you are turning as well as braking.

(2) if you start to lose control of the bike, or you have to respond to an emergency (e.g. to avoid a collision) and you are not in gear, you can't apply any power to the bike until you have got back into gear - by which time you might be sliding along the road and not riding the bike at all.

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  • So, i should keep the clutch pressed (cutting the engine and rear wheel off) or not ?
    – Somjit
    Commented Jul 12, 2021 at 19:59
  • @Somjit So, did you read point 1? Seems clear enough...
    – Solar Mike
    Commented Jul 12, 2021 at 20:12
  • @SolarMike yeah, but jwh20 s comment kinda confused me
    – Somjit
    Commented Jul 12, 2021 at 20:13
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    @Somjit that is because jwh20 is wrong and the answer is good.
    – Solar Mike
    Commented Jul 12, 2021 at 21:05
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My previous answer was mistaken (I opted to leave the mistake visible, rather than edit it).

From Merriam-Webster

declutch intransitive verb de·​clutch | \ (ˈ)dē+ \

: to disengage a clutch

: to put out of action by releasing a clutch

"releasing a clutch" is the place I got confused. Although we release a lever on the handlebars, the releasing of the lever actually engages the clutch.

So, the answers to your question are:

  1. (What is it saying?) The manual is recommending that you never PULL the lever (disengage the clutch) at high speeds while braking.
  2. (Why?) Doing so could suddenly change your braking situation, in a way that could be difficult to deal with.

With this definition, the recommendation makes a lot more sense: Once you've already started braking, you should not also pull the clutch, as this would change the profile of your braking situation. Doing so suddenly, and at high speeds could introduce all kinds of instability that could be difficult to manage.

Now I certainly don't think it's recommending as an alternative "leave the clutch engaged while you brake," that would clearly not work. I think the implied recommendation is to clutch first, then brake.

Are there ways to declutch while braking and not die? Probably. But the manual is interested in helping riders operate the motorcycle in the MOST safe manner, and this maneuver is not MORE safe than other options, such as releasing the brake, THEN declutching, then resuming the brake (not rapidly).

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  • It is saying to leave the clutch engaged while you brake at high speeds. Only when you get down to a slow speed should you declutch. This is exactly what you would do in a manual transmission car, you only press the clutch when you are going to drop down a gear or are about to stop.
    – HandyHowie
    Commented Jul 13, 2021 at 14:41
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"Declutching" refers to releasing the clutch lever... aka ENGAGING the clutch.

In layman's terms: it's recommending that you NOT use engine braking AND mechanical braking at the same time, especially at high speeds.

There are a number of reasons you might want to avoid this, not the least of which is that it makes it easier to drop the engine speed too low, and kill the engine. Doing this at high speeds is not immediately life-threatening, nor immediately engine-threatening, but it does introduce more problems rather than solving problems.

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    If to 'declutch' meant 'enage' the clutch, why would you have been free-wheeling at high speed? That is certainly not recommended. Commented Jul 12, 2021 at 22:59
  • As to your question, there are a number of reasons you might be free-wheeling at speed, not the least of which is shifting. But, I got mixed up in the clutch lingo again, Merriam-Webster says that "declutch" means to DIS-engage the clutch, so my answer is mistaken. I'll provide an alternate answer.
    – Matt
    Commented Jul 13, 2021 at 13:06

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