Mounting the fan slightly offset from center then provided plenty of clearance.
Camshaft Clearance Considerations
The original mechanical fan was mounted to the front of the camshaft. Accordingly, the camshaft protrudes from the front of the engine towards the radiator and consumes valuable space where the new electric fan could otherwise be located.
One way of dealing with this interference issue is to mount the fan so it is offset from the camshaft, away from the center of the radiator. Alternately, the camshaft tip can be trimmed to provide additional clearance. Or a combination of both methods can be used.
Forum member Exploring/Carolina illustrated this combined approach in
the following two photos. First, the camshaft tip was cut so it barely extended
beyond the camshaft holder seal.
Mounting the fan slightly offset from center then provided plenty of clearance.
In
this
CX/GL forum thread, forum member kureus removed the seal and plugged
the camshaft holder to prevent potential oil leaks as shown in the following
two photos.
Alternately, a 650 front camshaft holder can be used if available. In these
photos, camshaft holders from a 500 and a 650 are shown side by side.
Installation requires the camshaft tip to be cut off even further. Care must
be taken to ensure no metal filings end up inside the engine.
There is plenty of clearance if a 650 camshaft holder is used with a Ducati
fan.
Disclaimer: After comparing the 500 and 650 camshaft housing dimensions I believe to be important, my conclusion is there are no problems with this swap. But there is always the possibility I may have missed something, so be aware there is an element of risk should you choose to proceed with it. After 20,000 miles at the time of this writing, though, my 500 seems to have no problems after the swap.
Electric Fan Conversion Justification 500
only
Tachometer Cable Screw Replacement 500 and 650
Electric Fan Selection and Mounting 500 only
Camshaft Clearance Considerations 500 only
Fan Power Relay 500 and 650
500 Radiator Temperature Switch 500 only
650 Radiator Temperature Switch 650 only
Fan Always-On Modification 500 and 650