|Posted on Friday, October 15, 2021 - 08:26 pm: ||
'09 1125cr with "Race Only" ECM.
At about 40K miles my left radiator fan has failed. I've replaced it with a "Spal 30103013 5.2" Paddle Blade Pusher Fan" that I bought on ebay. It is a perfect fit, without modification, for either side fan. The fan chassis, electrical connectors and lead length are identical to the Buell OEM fan.
Now the question:
My right side fan draws air in the front of the scoop, through the radiator, through the fan and blows out into the middle of the bike.
My left side fan does just the opposite, drawing air from the middle of the bike, through the fan, through the radiator and out the front of the left scoop.
It seems to me the fan should not be pushing against the natural flow air in the scoop. What gives? Which way do your fans blow?
|Posted on Saturday, October 16, 2021 - 02:21 am: ||
Indeed air should toward the rear. I've replaced left fan too, right one fans on. Got replacement off eBay.
|Posted on Saturday, October 16, 2021 - 05:02 pm: ||
I double checked the polarity and rotational direction of the OEM fan that I removed (it still kind of works) and compared it with the new, replacement fan. They are identical. Therefore I suspect that my original fan was going against the "natural" air flow since I bought the bike new in '09.
This got me wondering if there was perhaps some logic in the ECM that sensed when the bike was stopped and reversed the fan's rotation so it would blow hot air away from the rider and out the front of the scoop AND then again reverse the flow when the bike was underway and at speed as to take advantage of the natural air flow. This notion seems far fetched but I wouldn't put it past some thoughtful engineer's design who experienced being roasted with hot air from the fan while waiting at a traffic light.
I've tried to confirm the direction the air blows with my hand. I can easily sense it when stopped - it is out the front of the scoop on the left fan and in the scoop on the right fan. I've tried to sense it while underway, in gear and under power to see if it reverses direction. I'm pretty sure it is in the same direction as when stopped but I'm not one hundred percent confident given the presence of ambient air flow.
So, I reversed the wires in the left fan's connector. Now, when the bike is stopped, both fans blow in the "natural" direction.
I'm wondering if others have their fan mis-wired, reversed as I apparently have.
Please confirm that the air flow in your left fan is "natural", that is in the scoop and out the fan into the middle of the bike when it is stopped. Thanks.
(Message edited by pwillikers on October 16, 2021)
|Posted on Sunday, October 17, 2021 - 11:12 am: ||
Defiantly in at the scoop exiting at the centre on both fans, sounds like an error in the wiring either in the bike or the fan, the blades in the fan are made to work in one direction only, they will move air if run backwards but not efficiently.
|Posted on Tuesday, October 19, 2021 - 09:28 am: ||
Thanks. Since I swapped the wires in the left fan connector, all is well with air flow.
Now on to the clutch which has started slipping. :-)