I bought my CForce 500 HO used about a year ago and the previous owner had bypassed the fan switch and put a rocker switch on the handle bars. After a bunch of searching I found NAPA PN 143-5040 is a direct replacement for the radiator mounted temp fan switch. Cost is about $20 and the connector is the same as the old switch. I couldn't find the specs for this switch but it seems to switch the fan on a 5 bars on the temp gage and off at 4 bars so I feel pretty comfortable about its operation. The switch is made in Japan and also has PN BS-506A on the box. Hope this helps someone.