What would cause this - slow start when cold?

[Condi]

Been having an issue with my Fireblade being very slow to start when cold. Fuel pump primes, battery has good voltage and the engine seems to turn over fast enough, but it takes a long time to fire. Then for the first few seconds it feels like it's bogging down, and after that is fine aside from a little hunting at idle. When riding it's pretty much perfect, and starting from hot is on the button.

I've replaced the fuel flow regulator, it's also had a full service fairly recently including valve clearances and injectors checked, and is running a Power Commander with the correct map. I do need to do the cam chain tensioner as you can hear that especially when cold, but any other ideas? Has air, has fuel, has spark - should go!!

Slow start;



Hunting a bit

Edited by Condi on Wednesday 7th October 17:24

[TorqueDirty]

I'm no mechanic but it sounds like it is taking ages for the fuel to be delivered to the injectors. I'm more used to carbed bikes but I could a leak in the fuel pipe supplying the injectors cause be this issue?

[trickywoo]

It would be worth testing the air temperature sensor as it seems that the ecu might not be enriching the fuelling enough on cold starts.

[Condi]

trickywoo said:

It would be worth testing the air temperature sensor as it seems that the ecu might not be enriching the fuelling enough on cold starts.

Would that be a different reading to the thermostat temperature? The coolant gauge appears to be correct.

[trickywoo]

Condi said:

trickywoo said:

It would be worth testing the air temperature sensor as it seems that the ecu might not be enriching the fuelling enough on cold starts.

Would that be a different reading to the thermostat temperature? The coolant gauge appears to be correct.

Yes. It’s a sensor in the air box. Part number 37880P05A00

[Condi]

Thank you, I'll have a look at it.