Cold motor

[esege]

My ST have 1.400 km and it seems to have problems with cold motor. The motor starts well in cold days in the morning but the idle RPMs are very unstable, make some missfires and “coughs”…… after several minutes over 70 or 80degrees Celsius all goes better but the idle RPMs are still a little unstable. Its normal???
Tks and regards.

 

[20valves]

That's not normal in my experience. On cold start up, I get a high idle for a bit, say 1,400~1,500 rpm, then it settles to about 1,050 when it reaches operating temp and it stays there. I'd have your EFI balanced and make sure your oxygen sensor and other EFI components are all working correctly. Good luck.

 

[Don in Lodi]

::026:: Not normal.

 

[esege]

The problem was very simple but very difficult to solve. By error the oxygen sensors where plugged wrong ie sensor 1 to imput 2 of the ECU and vice versa. The connectors are of the same color and the cables also. Learned lesson.

tks for all

SG

 

[Don in Lodi]

::008::

 

[Karson]

The problem was very simple but very difficult to solve. By error the oxygen sensors where plugged wrong ie sensor 1 to imput 2 of the ECU and vice versa. The connectors are of the same color and the cables also. Learned lesson.

tks for all

SG

The were flip flopped incorrectly from the day you bought it?

 

[esege]

No. Was my mistake while installing a Shift Light :'( and cost to me USD 400 for 8 hours at the yamaha workshop.



I addmit my mistakes, both plugs are almost equal, only a small difference in one wire.

Regards

 

[snakebitten]

Well, we all thank you for a lesson we ALL now learned. Thanks for funding it. You're a giver!

 

[Bombman]

Definately not NORMAL. All modern bikes with ECU and fuel injection are setup to run on a closed loop which raises the RPM until it reaches a pre-set operating temperature, hense why when you first start up it is running around 1400-1500 RPM, then peters off to around 1350. Carbeurated bikes do not have this, which is why they have a air control valve.