Radiator fan switch
 

Hey guys just looking for abit of help, i am aware the pointy sv fan comes on at more than 100 degrees, well i have never been near 100, i looped a wire to the fan and it spun perfect, i was wondering if there was a way to split this connection to the thermostat and have the fan to run on a switch on the handlebars, i do alot of town traffic and the bike gets hot quick if i dont get moving.

In the haynes manual its referring to fault finding with the thermostat and it states that if it is found to be faulty the bike can be ridden without it BUT it will take longer to warm up AND it must be replaced asap, is there a way to fit a switch without disconnecting the thermostat, so that the thermostat works as it should and then when i need the extra cooling i can flick the switch, anyone can help with this?

Re: Radiator fan switch
 

Just to clear up a couple of things first.

The fan switch is a "temperature controlled switch", the "thermostat" as referred to is the device buried in the coolant circuit (between the cylinders on an SV) which diverts the coolant from going round and round the engine during warm-up, and off to the radiator once it reaches a high enough temp.

Thermostats are designed to fail "open" so the coolant goes to the rad even when cold, so it takes a long time to warm-up and generally runs too cool usually, all not ideal. Removing thermostats isn't recommended, but in an emergency can be done if necessary. Replace as soon as possible.

As for your question re. the switch, yes you can do it if you feel it's necessary. The fan switch is designed to deal with hot running when stationary or in slow traffic, but if you will feel happier having a manual switch you can easily do it.

I think the SV switches are 2 wire jobs, the switch simply connects the 2 wires together whan it closes (hot). All you need to do is join a separate wire to each of these 2 and run them to your manual on-off switch, the original wires stay connected to the radiator switch exactly as before. Thus you have 2 switches in "parallel", either one of them will switch the fan on.

A warning lamp ould be a nice touch to remind you it was on, exactly how this is done depending on whether the rad switch is on the feed or earth side of the fan (not sure). One way you need a 12V feed to the lamp and earth it via the "on" switch position, the other way you earth the lamp and feed it from the "on" side of the switch, do-able either way.

Some rad switches have a single wire and switch to earth, but I don't think the SV is like this.

Re: Radiator fan switch
 

Thanks for the help its started to make good sense to me now, yeah i agree a warning lamp would be a nice touch i'm going to see what i can manage this weekend.

Re: Radiator fan switch
 

I hope you mean to add a switch in addition to the built in fan switch so either will turn on the fan. It would be seriously bad to only have a manual switch and then forget to use it when needed.