does any body know why my fan only comes on when i turn the engine off , (xb9 05)
not running when in traffic.

The fan is an attempt to get round the engineering faux pas of putting the rear cylinder of an air cooled motor withing a perimiter beam frame. It is thermostatically governed so that the oil in the rear cylinder does not get so hot that it starts to break down. When the motor is running the oil should be being pumped round and therefore not just sitting a cooking the thermostat has different settings depending on whether the motor is running or not.

From memory and open to correction I think that with the motor running the fan will activate at 220C and stop at 180C. With the motor off the fan will activate at 180C and stop at 160C. One little entertainment is heat soak that a motor will suffer when you turn off the ignition. This will sometimes allow you to turn off the ignition and walk away from your bike before the fan starts. Scares the bejasus out of anyone stood next to the bike

_________________
Be seeing you

I

Ye thanks for the reply still think theres something wrong with fan.

Why do you still think there's something wrong with the fan They all do that sir

_________________
Wear the fox hat

Because it's still working! It's passed its designed-in point of failure.

_________________
Good in straight lines
2001 X1 "The Tart's Handbag"
2001 FZS1000 "The Fridge"

One commuter's experience on poorly tuned XB, five miles & four stop lights one-way:
Hot summer afternoon (90+F), fan kicks on while idling in stopped traffic at first light.
Rainy day or cool fall afternoon (75-F), no fan in same situation.
Fan runs at key-off 90% of time, regardless.

Very similar conditions to most of my commuting (apart from the temperature, it doesn't drop to 90 deg F even at night ) I only get the fan running when I switch it off. This is due to having a RH scoop fitted

_________________
Wear the fox hat

ye fans crap same as everything on the freakin bike

The usual complaint is that the fan never switches off!

_________________
aka DrBagiva, DrBusqvarna, Uncle Knobhead

fan on fan off guzzis got it right stick the cylinders by your knees

Buell got it right too......until Erik had a brain fart and decided to put an air cooled engine inside a petrol tank

_________________
Mithered ta death.
92 MB
96 S2T
98 S1W
00 M2
01 X1
03 P3
10 CR