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inermittent fan failure
Posted: Sun Oct 05, 2014 10:58 am
by RobertWichert
So yesterday I am off-road on some OHV trails, trying not to fall (I
succeeded) and the temp starts going up as I am going up some slow first
gear hills. This doesn't bother me until I notice that the fan is not
coming on. I know it was working earlier in the day, so I am now pretty
worried since we are five or six miles from the road and it's mostly
slow going.
I let it cool down and tried the "ground the thermostat wire" check. No
fan. That's a valid check, right? Ground the thermostat wire and the
fan is supposed to start, right? It didn't. So I figure it is the
relay or the fan.
I ride it back to the road at a brisk pace to get air to the radiator,
and when I stop, the fan comes on. What the heck? Then it turns off
when the temp is at 3/4, which is higher than I remember. I seem to
remember it turning off at about 6/10.
Then it gets hot again, and the fan doesn't turn on.
Then it does. Still doesn't take it down to "about half gauge" where I
think it should go.
I'll be doing some trouble shooting today or tomorrow.
Your advice is appreciated.
--
Robert Wichert P.Eng. LEED AP BD&C
HERS I/II CEPE CEA
BPI CERTIFIED SF/MF GREEN POINT RATER
+1 916 966 9060
FAX +1 916 966 9068
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inermittent fan failure
Posted: Sun Oct 05, 2014 10:47 pm
by Norm Keller
Robert, you likely know but dropping often bends the fan shroud which can keep the fan from turning. That's the first thing I'd check. It can be seen by simply popping the side shroud, which will give room to work if needed. Second thing would be to check for power to the fan when the sensor wire is grounded. If fan power comes on and off with the sensor on and off ground, then look to the plugs. The fan relay is under the tank at the front and can be checked or swapped for the side stand relay which is under the side stand switch cover.
Before getting into surgery, the fan switch normally grounds to the radiator which is grounded by the ground wire attached to one of the three 6 mm fan mounting bolts. If the fan runs when the switch lead is grounded, but not when on the switch, try grounding the wire to the hex side of the fan (thermal) switch. If the fan runs when grounded to a point such as the end of one of the head fins but not to the radiator, the ground is disconnected, or otherwise open. I've seen this when someone didn't properly tighten the ground holding one of the fan mounting bolts.
If you haven't put a length of door seal rubber around the radiator side of the fan shroud to seal the shroud to the fan, this might be worth doing as a loose bolt can break the shroud and leave a jagged end to rip the radiator. The seal rubber protects against that and helps stop air from infiltrating between rad and shroud which helps cooling.
The wiring information I posted links should cover the testing but more than happy to help.
Norm
klr650 gen 1 brake rotors
Posted: Mon Oct 06, 2014 2:20 am
by jet_doctor2002
Thanks for the reply Fred.
Do you handle the DP brake rotors?
I am not whining about a little rust where the pads rub, these rotors are solid rust. I have been riding for 45 years and have never seen anything like it. It is like they skipped half of the production steps and shipped the rotor blanks. The rotors on my 10 year old Toyota truck look better. Totally inexcusable on a motorcycle. If nothing else, I hope that no one else wastes their money on EBC rotors.
Thanks,
Doug