F650 GS 2004 Twin Spark "Irregular Idle"
F650GS model 2004 twin spark well maintained, 65,000 Kms, recenty
serviced Oil, both filters, spark plugs replaced, Iridium spark plugs,
K&N filter, no other modifications
During the last weeks I am facing the following problem:
1. When motorbike is started the rpm is fluctuating between 1500 rpm
and 2200 rpm (not steady up and down)
2. Sometimes when it has been stopped for about 20 minutes and then
restarted the idle rpm goes up to 3500 and then slowly –slowly to the
normal figure 1500rpm.
3. Just to mention that this is happening always at the beginning
(when it is started) and after a while (5-10minute) it reaches the
normal figure 1500rpm
4. A couple of days ago, when it was quite cold about 10 degrees
Celsius, and when moto was initially started it went up to 3000-3500
rpm reaching the normal idle rpm after 5 minutes driving .
5. Moreover when motorbike is in this phase (high rpm after starting)
and you release the clutch without increasing the throttle, the rpm
are increased automatically (like sensing that more power is required
and the “governor” is being involved). After a couple of minutes the
RPM are lowered automatically, but this behavior is noticeable.
I did check all connector with sensors, checked for leaks, opened and
cleaned the “cold starting idle motor/relay” (small black barrel on
the throttle body) and then adopted the throttle (by clearing the
values and re-adapting procedure given by BMW) after throttle removal
and cleaning with my “GS911” interface. But again this morning the
motorbike started with 3500 rpm (temperature about 15 degrees
I have checked the errors in the ECU and even after testing them with
procedures given by the “GS911” no error appeared.
I have replaced the following:
A. idle control valve
B. Ar intake temperature sensor
C. Coolling water temperature sensor
D. Cleaned all the contacts existing at the side of the cylinder
(generator, pickup sensor etc...) including the engine grounding.
E. Did the adaptation by using the GS-911 when Idle control valve on
the throttle body is removed/cleaned.
Same behavior as above described.
All above items were replaced with brand new original BMW spare parts
Has anyone similar experience or can guide me through, what to check
by using the GS911 interface?
I am now suspecting the O2 sensor.
I have to stress the fact that when engine is cold (just started) it
is working fine (idle 2000 rpm dropping to 1500 rpm. When it is warm
(engine working temperature) we face this irregularity in the idle