CB650R Throttle stuck at 4000rpm when applied following cold start

[ellinara]

Hi everyone first post on the 650 community.

I have had the pleasure of owning 2 CB650R (2022 and 2023) which following a cold start and application of the throttle can get stuck at 4000rpm. I doubt it is a mechanical issue as both bikes have done this and have both been examined by my dealer while under warranty. I had one Honda tech tell me to check my coolant reservoir to ensure that the coolant temperature sensor is submerged.

Alternatively, could this be ECU strategy where once the throttle is applied following a cold start the ECU holds it there to warm up the engine?

Thank you for your time

 

[miweber929]

Both have done that? First I’ve heard of this issue.

 

[ellinara]

Hi Mike,

I honestly think that it might be how I use the bike where I would literally turn it on in the morning and ride off. Perhaps I am inadvertently entering some sort of test setting? Both bikes were purchased new and I am the only owner.

 

[miweber929]

Hi Mike,

I honestly think that it might be how I use the bike where I would literally turn it on in the morning and ride off. Perhaps I am inadvertently entering some sort of test setting? Both bikes were purchased new and I am the only owner.

So if both did it, I would say it's some sort of "programmed in" anti-stall thing and normal. I would suggest giving it a few moments to warm up if you can. Doesn't need to be fully warm but what I always do is start the bike, put on my gear and go.

 

[Redrocket]

My 2023 CBR650R bought new has always run at 2,000rpm on a cold start. It needs a couple of minutes at least for the revs to die down before I ride off. My car, a Mazda, is the same, though the revs die down more quickly. In the latter case there is advice in the owners handbook that this is normal and the the car should not be driven until the revs have normalised. If I do this it is a bit hairy driving out of the cul de sac.... The issue is less pronounced on both in the warmer months. I don't rev either until setting off. I can't say I like the notion of a stone cold motor starting at 2,000rpm; 4,000rpm sounds to me like something is wrong, though some older Kawasakis used to start at 4,000rpm and had camshaft wear to prove it...I wonder if it has something to do with the heating stage of the cat. I'm no expert on these bikes but in my view starting at 4,000rpm is not normal.

 

[Brammers]

On my 650f if I start the engine before the fuel system has primed and settled it runs at 4k for a little while until the ecu stops having a panic attack.

J

 

[helennasmithh]

Hi everyone first post on the 650 community.

I have had the pleasure of owning 2 CB650R (2022 and 2023) which following a cold start and application of the throttle can get stuck at 4000rpm. I doubt it is a mechanical issue as both bikes have done this and have both been examined by my dealer while under warranty. I had one Honda tech tell me to check my coolant reservoir to ensure that the coolant temperature sensor is submerged.

Alternatively, could this be ECU strategy where once the throttle is applied following a cold start the ECU holds it there to warm up the engine?

Thank you for your time

It is possible that this is an ECU strategy designed to keep the engine at a steady RPM after a cold start to warm it up efficiently, especially if both bikes behaved the same way. Checking that the coolant temperature sensor is submerged, as the Honda tech suggested, could also be key, as the ECU might rely on accurate coolant readings to manage idle RPM during warm up.

 

[Redrocket]

I still feel that 4,000 rpm is not normal for a cold start, assuming that the diagnostic self-test is allowed to complete before the engine is started and the throttle is left alone. 4,000rpm seems to me to be way too high from zero revs before the oil has begun to circulate.