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Discussion Starter #1 (Edited)
I've noticed my '19 Thruxton R takes few cranks to start after overnight stay in not particularly cold weather (+11C in the morning).
It usually take 2-3 seconds. Is it normal?

UPD: Recorded sound:

P.S. Sorry for stupid question. It is a new bike and I am still getting used to it.
 

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Discussion Starter #3
So one suggestion is to try lower octane gasoline? I can certainly try that.

Since this is a new bike I think the battery is OK. So my worry is anything else is needs attention...
 

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Sounds like fuel starvation to me. Seems as if the initial, first in the day attempt at starting, the ECU fails to get a signal to deliver fuel. Probably would have kept on cranking even longer. By the second attempt fuel is delivered and the engine starts. Try just a one second stab at the starter on the initial start and see if she fires up on a subsequent attempt. Probably requires a trip to the dealer to reprogram the ECU.
 

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what Bigroy said, When i asked my dealer why my TTR was not starting on the first go he stated that it was normal, which i have also read and heard by members in the Facebook groups as well as this website. My bike has done this since 2017 when i bought brand new always fires up on the second crank after a long time sitting. if the engine is warm starts right up on the first try
 

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I wouldn’t actually say it was “normal” and any dealer saying that is really just fobbing you off. It does happen quite broadly, although doesn’t effect everyone, doesn’t seem to do any harm and seems always only to occur on the first push, so perhaps is not a fault as such and not something to worry too much about, but it should not be considered normal. Rather it should be viewed as a common, albeit probably benign, problem. Quirk perhaps?
I overcame it by using lower octane petrol, which still exceeds the minimum standard for these engines. It still happens once every 100 or so cold starts and is still bloody annoying when it does. I’ve accepted it and can (now) live with it.
 

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Again, let the needles do their sweep after the key is turned to ON. Then, hold the start switch until the bike is running, not just until it kicks a few times and quits. This is the technique suggested in the owner's handbook.

It's a different bike and ECU, and almost a completely different design philosophy, but that's how my Ducati GT1000 starts itself. You touch and release the start button, and the start motor continues cranking until the engine is running. The start sequence is then terminated automatically. It's a little eerie until you get used to it. A second start attempt is never needed.
 

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Just for the record...

I use premium fuel. I turn the key to the on position, wait for the warning lights to go through their sequence, (2-3 seconds), press the start button and the engine cranks and starts within 1 -2 seconds. First time, every time for the past 4 years and 40,000 km..

That is how all the water cooled classic twins should start. I they don't, it is the ECU program that is the problem.
 

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I’m only aware of the problem occurring with the HP motor in the Thruxton and Speed Twin. I’ll try holding the button longer if/when it happens again but as it always started immediately on second push that still seems the easiest work around.

I changed to Premium fuel (from Ultimate) and that’s what fixed it.
 

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Discussion Starter #11
As I side note, as an engineer (albeit electrical one) I could not help wondering what is the physics behind using lower octane gasoline in this situation :)
 

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Your motorcycle fails to start on the first attempt because it is not receiving fuel. On the second attempt, the engine fires up without problem. Is the culprit a vapor lock caused by the use of premium fuel ? Or, more likely a software issue with the ECU ?

A vapor lock can develop when a motor is allowed to idle for a long time on a hot day, is then shut down and then attempted to be restarted shortly there after. Since the problem occurs on the first cold start of the day, it makes the likely hood of a vapor lock very unlikely.

To solve the problem, try switching to mid grade fuel. If that doesn't solve the issue, try updating the ECU program.
 

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Vapor lock might be a problem with carbureted engines, but not those with high pressure fuel pumps like the WC twins. When the key is turned ON you can hear the fuel pump run briefly while it delivers fuel at full pressure. Air (there won't be much) is purged at the same time. Wait to engage the starter until this process is complete and the needles have completed their sweeps. Fuel RON plays no part.
 

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Vapour lock as it came to be called is caused when a carbureted engine with a high intact tract volume, think an old iron 4, 6, or 8 cylinder lump with a single carby and a big lumpy manifold, gets too hot and vapourises too much fuel causing a vastly over rich mixture within the confines of the manifold, or even vaporises the fuel in the float chamber so there isn't enough fuel to get into the manifold to provide the correct proportions of fuel to oxygen. The first results in too much fuel, not enough oxygen, to fire, the second scenario produces not enough furl in the mixture to ignite. The only remedy was to take off the aircleaner, and wait for the whole shebang to cool down a bit to return the engine to within the designers heat parameters.

I don't see how that could happen on a 1200 with precisely controlled fuel injection and a very short. low volume inlet tract. Far more likely an ECU issue, and probably to do with 'Safety".
 

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Vapor lock might be a problem with carbureted engines, but not those with high pressure fuel pumps like the WC twins. When the key is turned ON you can hear the fuel pump run briefly while it delivers fuel at full pressure. Air (there won't be much) is purged at the same time. Wait to engage the starter until this process is complete and the needles have completed their sweeps. Fuel RON plays no part.

Fuel injected engines with fuel pumps located inside the fuel tank are indeed less likely to encounter vapor lock than those with external fuel pumps and carburetors - but it is not unheard of.

The higher the volatility of the fuel, the more likely it is that vapor lock will occur.

I don't believe vapor lock is the issue here, I was merely grasping at straws to explain why lowering the octane might be the cure.

I believe the problem may lie with the ECU not delivering a signal to the fuel injectors on that initial, cold start of the day. A subsequent attempt clears the problem, not unlike a PC or a modem requiring a reboot to clear a problem.

https://en.wikipedia.org/wiki/Vapor_lock
 

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I just read an article on this, it's called deadstarting I believe that's it. Many owners of new bikes are complaining about it. There are so many sensors on new engines now it takes a few revolutions for the computer to source all of it's info to start the motor. Think of it as a safety device so your motor doesn't lunch itself because one cylinder has too much fuel in it and the motor attempts to start . That computer has to figure out the temp, available fuel, spark, timing, kick stand position, etc etc. If your computer just delivered spark to a motor that wasn't ready it could have some bad results. Especially with the tolerances of a today's modern engines. Just think of the technology (both computer and mechanical) in a car that merely shuts itself off and then restarts instead of idling at a traffic light, it's mind boggling! Hopefully that tech is not coming to motorcycles.
 

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I just read an article on this, it's called deadstarting I believe that's it. Many owners of new bikes are complaining about it. There are so many sensors on new engines now it takes a few revolutions for the computer to source all of it's info to start the motor. Think of it as a safety device so your motor doesn't lunch itself because one cylinder has too much fuel in it and the motor attempts to start . That computer has to figure out the temp, available fuel, spark, timing, kick stand position, etc etc. If your computer just delivered spark to a motor that wasn't ready it could have some bad results. Especially with the tolerances of a today's modern engines. Just think of the technology (both computer and mechanical) in a car that merely shuts itself off and then restarts instead of idling at a traffic light, it's mind boggling! Hopefully that tech is not coming to motorcycles.
This is indeed a possible explanation to the problem encountered when starting for the first time from a cold engine, but it does not explain why the problem is resolved by simply lowering the octane of the fuel.

I still believe the problem lies with the electronics of the ECU and not the chemical properties of the fuel being used.
 

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Discussion Starter #18
Another thing I've noticed, is that when I press start switch when cold, it will turn the engine but it will not start no matter how long I hold it.
If I let it go and try again, it starts. Here is another video I took showing this.

 
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