I have purchased a low mileage1993 Triumph Trident Sprint CRK Cafe Racer Conversion which i have had a number of problems with one of which is with the cooling system. When i ran the bike up to temperature in my garage over the Xmas break the high temp orange warning light came on but the fan did not cut in. Further investigation revealed the fan was faulty & it was subsequently replaced. The fan still failed to operate when the engine was hot & the orange high high temp warning light came on so a new fan switch was purchased / fitted into the radiator & everything appears to be working now although i am puzzled as to why the fan goes off when the ignition is switched off even though the engine / coolant is still very hot. For info the feed to the fan switch is permanently live which is borne out when you pull the wires off the switch & connect them with a link wire the fan then runs so why does it not continue to do so after the ignition is switched off?
The way you describe it, I'd suspect the fan switch. Did you replace it with an original switch or did you go for any of the car switches that will also fit?
Try putting a temporary auxiliary earth in ? Run up to cut in Temp and switch off ignition, see if auxiliary earth sorts it ! Maybe the earth wire is routed wrongly ? Someone may have muddled up a wire somewhere when the bike was modified ??
