Cold vs Hot start.

[PeterSX]

This may all be a figment of my imagination.... but .....

I've noticed that in the current cold weather my bike doesn't seem quite so responsive and doesn't pull as well at low revs. But today I had to stop off at an ATM on the way to work, and when I restarted it, it felt like it was running better.

So on the way home I did a similar "stop" and again after the restart it felt to be running better with crisper throttle reaction and less vibration.

Am I imagining this or is there something that could be going wrong when starting it up form cold ?

PeterO

 

[B4ndit]

Some people say bikes run better in the cold.

For me dry roads do it. Never mind if its cold or hot.

 

[Lighty]

Maybe there is an underlying problem with your bike, I deal with cars, and the ecu generally resets after a switch off, so perhaps you start with a clean slate "so to speak"
Might be worth getting it plugged in to see if there are any fault codes in the ecu.

 

[stolzy]

Maybe there is an underlying problem with your bike, I deal with cars, and the ecu generally resets after a switch off, so perhaps you start with a clean slate "so to speak"
Might be worth getting it plugged in to see if there are any fault codes in the ecu.

I had a similar issue in an oldish BMW 5 series. Sometimes the heater would come on full hot until you stopped and turned it off for a few moments

 

[Pukmeister]

This may all be a figment of my imagination.... but .....

I've noticed that in the current cold weather my bike doesn't seem quite so responsive and doesn't pull as well at low revs. But today I had to stop off at an ATM on the way to work, and when I restarted it, it felt like it was running better.

So on the way home I did a similar "stop" and again after the restart it felt to be running better with crisper throttle reaction and less vibration.

Am I imagining this or is there something that could be going wrong when starting it up form cold ?

PeterO

Both my 1200's have behaved exactly the same, for no logical reason. After a brief stop and restart they always run much smoother ??

 

[mark2jag]

This may all be a figment of my imagination.... but .....

I've noticed that in the current cold weather my bike doesn't seem quite so responsive and doesn't pull as well at low revs. But today I had to stop off at an ATM on the way to work, and when I restarted it, it felt like it was running better.

So on the way home I did a similar "stop" and again after the restart it felt to be running better with crisper throttle reaction and less vibration.

Am I imagining this or is there something that could be going wrong when starting it up form cold ?

PeterO

maybe its haunted!!! I'm like that in the mornings too especially if they are cold. i always work better after a short break. preferably not an arm or leg though...


Seriously though it may just be a consequence of getting a bit warmer engine wise.


Mark

 

[PeterSX]

Thanks for the replies. I've just been out on it again, and now I'm sure it isn't my imagination.

Lets imagine for a moment that it has a face....

After a cold start it has a grumpy face.
From a hot start it has a smile on it's face. It just feels like it is a happier engine.

The grumpy face doesn't turn into a smile even when it has warmed up. It needs a stop and restart to get its smiley face.

Any engine gurus got any ideas on possible causes ?

I'll have to get it to the dealer and leave it overnight or something so they can ride it cold./

PeterO

 

[trainman]

Thanks for the replies. I've just been out on it again, and now I'm sure it isn't my imagination.

Lets imagine for a moment that it has a face....

After a cold start it has a grumpy face.
From a hot start it has a smile on it's face. It just feels like it is a happier engine.

The grumpy face doesn't turn into a smile even when it has warmed up. It needs a stop and restart to get its smiley face.

Any engine gurus got any ideas on possible causes ?

I'll have to get it to the dealer and leave it overnight or something so they can ride it cold./

PeterO

an educated guess - there are sensors for air intake, oil and cylinder head temps, these all feed the ECU and help determine fuel maps
i imagine that any time spent with the engine off will cause one,2 or all of these to change quite a lot, it maybe that then on start up, even with a warm engine, you get a bit more fuel than when fully hot, hence the feeling of a difference?

 

[rml]

I think I can add mine to the grumpy/haunted list.

I've recently been experiencing similar behaviour, if started cold (5 deg C or less)
the engine feels as if it is laboured/misfiring, the smooth power from
the mid range is gone and the bike is hesitant to accelerate. After a restart
all is fine.

I'd thought possibly the flappy exhaust thing or the ecu is getting it's
knickers in a twist.

Be interested to hear what the dealer says.

Oh mine is a 2011 twin-cam.
Cheers
rml

 

[PeterSX]

I think I can add mine to the grumpy/haunted list.

I've recently been experiencing similar behaviour, if started cold (5 deg C or less)
the engine feels as if it is laboured/misfiring, the smooth power from
the mid range is gone and the bike is hesitant to accelerate. After a restart
all is fine.

I'd thought possibly the flappy exhaust thing or the ecu is getting it's
knickers in a twist.

Be interested to hear what the dealer says.

Oh mine is a 2011 twin-cam.
Cheers
rml

Sounds very similar symptoms.
Mines about 14 months old now.
Peter

 

[davedyer]

an educated guess - there are sensors for air intake, oil and cylinder head temps, these all feed the ECU and help determine fuel maps
i imagine that any time spent with the engine off will cause one,2 or all of these to change quite a lot, it maybe that then on start up, even with a warm engine, you get a bit more fuel than when fully hot, hence the feeling of a difference?

There may be an element of heat soak going on. When the engine starts from very cold, although the engine warms up, the sensors my continue to lag behind and never catch up. They fail to reflect the true running temperature when the engine is operating in the very cold temps, hence the rough running. The time stopped allows heat to soak into them and when the engine restarts they give the ECU a more accurate picture of the temperature map and the engine runs more sweetly.




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[PeterSX]

There may be an element of heat soak going on. When the engine starts from very cold, although the engine warms up, the sensors my continue to lag behind and never catch up. They fail to reflect the true running temperature when the engine is operating in the very cold temps, hence the rough running. The time stopped allows heat to soak into them and when the engine restarts they give the ECU a more accurate picture of the temperature map and the engine runs more sweetly.
Sent from my iPad using Tapatalk HD

In which case should sitting stationary for a while have the same effect ? Or is the oil cooling going to keep the temp down ?

PeterO