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Adding my 2 cents worth.

I doubt that the batter is the culprit here. Probably fuel supply\

If you do go the route of fuel additive, let me recommend the regular use of LUCAS fuel additive. I use it in all my vehicles constantly. On my antique BMW which the carbs weren't that good, after cleaning the system, I started using Lucas, and from then on, the fuel system stayed spotless! Never had the problem again!

Since it mixes at a 400:1 ratio, it goes a long ways. I purchase it in the gallon jug, which lasts a looooong time on all my vehicles, 2 cars, 1 riding mower, and one motorcycle.
Is that stuff kind of thick like gear oil?
 

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Thanks. I was thinking the battery as well. I tried the clutch trick this morning and it fired right up so I’m thinking maybe the battery might be weak as I believe it’s original to the bike. 7+ years
It is due to worn Neutral Sensor (it gets shaved off over time; sends off-spec signal/resistance to ECU, resulting in no ignition spark).
 

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Turns out there is no issue with battery or electrical when trying to start. I ended up putting non ethanol fuel (premium here in Canada) in my almost empty tank. I didn’t mention this before as I was out of gas and just added some of what I had in a Jerry can. I always use premium in my lawn mower and snow blower. Since using this other gas, I have had no issues with starting. So I’m assuming that all this gas sitting around since COVID has started to go bad. Anyway I will be only using premium gas in all my vehicles unless I can source non ethanol fuel in 87 octane somewhere.
 

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I have recently (about 2 weeks) been observing some starting trouble on my bike on cold start. I can crank the engine, the engine keeps cranking at ~200RPM (?) without starting. I need to open a bit of throttle for it to start. It happens when I start the engine from cold in the morning, and seems to not have trouble when it is warm enough. Note that the temperature is not too cold now a days ( around 15-20C / 60- 70F ) and has started flawlessly at close to freezing.
The cranking suggests the battery is fine
My X has been having the same troubles.

Previously, cold or warm, the bike with rev to life with just a brief touch of the button. Now, it has developed the habit that it will "whir-whir-whir-whir" for a while, the starter turning the engine over, but it just doesn't catch the spark. Usually, if the engine is warm (having just ridden for a while) the engine will start immediately. But if left for more than 8 hours or so, it won't catch.

I checked the battery. It's fine. 100%. I checked spark plugs. I took it to the service shop and they tried starting it for several days, and couldn't figure it out.

Internet rumors seem to suggest it may be related to your clutch, or engine oil. The theory is that too thick of oil, or too much tension in gearbox, or something not 100% with the electrical switch hooked up to the clutch, is not cooperating with starting.

I don't know about any of that, and perhaps this is just coincidence, but I find that the beast starts easier if I hold the clutch in while starting, yes, even with it being in Neutral.
It is due to worn Neutral Sensor (it gets shaved off over time; sends off-spec signal/resistance to ECU, resulting in no ignition spark).
Same problem here with my 2018 CB500F with 11,000 km on the clock. The starter engine makes a strong and loud "whir-whir-whir-whir", but the main engine refuses to start. This suggests the battery is good (although I have had no time nor inclination yet to either test the battery with a voltimeter or check the battery terminals for signs of corrosion).

I have yet to try the trick of pulling the clutch while pressing the start button. If that solves the problem, I think @eds might be spot on with his remark about the worn Neutral Sensor (for the problem totally looks like the ECU is not letting the spark happen because reasons...).
 

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When it comes to poor starting I always start with basics, battery,fuel,plugs, check for spark, and fuel at the plugs,delve deeper if needed.
 

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Same problem here with my 2018 CB500F with 11,000 km on the clock. The starter engine makes a strong and loud "whir-whir-whir-whir", but the main engine refuses to start. This suggests the battery is good (although I have had no time nor inclination yet to either test the battery with a voltimeter or check the battery terminals for signs of corrosion).

I have yet to try the trick of pulling the clutch while pressing the start button. If that solves the problem, I think @eds might be spot on with his remark about the worn Neutral Sensor (for the problem totally looks like the ECU is not letting the spark happen because reasons...).
So, I've been four days now starting the bike with the clutch pulled, and the engine has started perfectly on first try every single time. So the battery is good, and CERTAINLY the problem is in the Neutral Sensor, which has worn out.
I'm somewhat mystified that Honda has this problem, generally known at least since 2016, in a 2018 bike. Don't they rectify engineering problems when detected? I expected better quality.
 

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Well you would have to ask yourself how many bikes have been sold and how many develop the problem it may only be a small percentage. Its like the gear shift linkage, i had a faulty one from new, but how many folk have had this problem. Could be Honda have a percentage policy. They ain't made like they use ta.
 

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So, I've been four days now starting the bike with the clutch pulled, and the engine has started perfectly on first try every single time. So the battery is good, and CERTAINLY the problem is in the Neutral Sensor, which has worn out.
I'm somewhat mystified that Honda has this problem, generally known at least since 2016, in a 2018 bike. Don't they rectify engineering problems when detected? I expected better quality.
So do you get a neutral light on the dash with this problem ?
 

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So do you get a neutral light on the dash with this problem ?
Yes, I do get the green Neutral light in the dashboard, but it flickers when I press the start button and the engine fails to start because of this problem. But if I press the start button with the clutch pulled, the engine starts successfully on first try and there is no flicking of the Neutral light in the dashboard.
 

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It appears the neutral light is connected separately from the ECU ignition logic. So, the neutral light is not a good indication/symptom.

The Neutral Sensor outputs resistance (ohms), a variable range of ohms (depending on the physical contact of the sensor "push-pin" against the shift-drum "neutral nodge"). A new Neutral Sensor appears to produce around 25 to 150 ohms (installed). A completely worn has 400+ ohms (still good enough for the neutral light to light up).

The early symptoms are:
1. Randomly, starting takes longer (instead of immediately). This progresses to consistently taking longer and longer. And then, randomly, won't start. (No, it is not due to weak battery).
2. Randomly, won't start until kickstand up.
3. Won't start until clutch is pulled. Eventually, this workaround will also become unreliable or stop working.

With hindsight, I would now test & replace the Neutral Sensor early.
 

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It appears the neutral light is connected separately from the ECU ignition logic. So, the neutral light is not a good indication/symptom.

The Neutral Sensor outputs resistance (ohms), a variable range of ohms (depending on the physical contact of the sensor "push-pin" against the shift-drum "neutral nodge"). A new Neutral Sensor appears to produce around 25 to 150 ohms (installed). A completely worn has 400+ ohms (still good enough for the neutral light to light up).

The early symptoms are:
1. Randomly, starting takes longer (instead of immediately). This progresses to consistently taking longer and longer. And then, randomly, won't start. (No, it is not due to weak battery).
2. Randomly, won't start until kickstand up.
3. Won't start until clutch is pulled. Eventually, this workaround will also become unreliable or stop working.

With hindsight, I would now test & replace the Neutral Sensor early.
Totally agree.

Now, let me ask: Will a replaced Neutral Sensor develop the same problem, time and time again? Is there an "alternative" Neutral Sensor of better build quality which can be used to set-up-and-forget about the problem? I want to solve this annoyance once and for all, for I have too many things on my head as to add this problem as a recurring, chronic, additional problem to my life.
 

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Totally agree.

Now, let me ask: Will a replaced Neutral Sensor develop the same problem, time and time again? Is there an "alternative" Neutral Sensor of better build quality which can be used to set-up-and-forget about the problem? I want to solve this annoyance once and for all, for I have too many things on my head as to add this problem as a recurring, chronic, additional problem to my life.
No. The Neutral Sensor "push pin" appears to be brass (soft metal), pushing against the steel shift-drum; the sensor is sacrificial. It is not expensive, and easy to change (except for 2016+ R models due to the fairing).

The Neutral Sensor "push pin" gets scraped every time the gear shifts across neutral, 1st to 2nd, 2nd to 1st.
 
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