Automotive type relays?

[ippytattoo]

I am sure this has probably been covered a million times but I can't seem to find it using the search or tech section. Is it neccesary to use automotive type relays if you are making your own wiring harness or are the bar switches rated for enough amps for a particular given circuit i.e headlight, ignition (kill switch), turn signals and the likes? The bike I picked up as a basket case had no wiring what so ever which is not a problem I do wiring as part of my daily job but I have nothing to base my assumptions on. I am using KZ400 switches as I got them for a very good price (FREE). I may end up using some automotive type relays just for safety but was wondering if they are really needed.

 

[Grinder]

The xs's never used any relays except for the electric starter as far as I know.

 

[bened]

If the switches your using are actually from a motorcycle, you probably won't have any problems running them without relays, but I am definitely using some on my build because the switches I'm running are only rated for 2-3 amps... Motorcycle wiring is no different from other vehicles, if the switch can't handle the load, it'll need a relay.

 

[tonyc]

I used 50 amp toggles for my own harness. I also fused them.

 

[angus67]

I used 50 amp toggles for my own harness. I also fused them.

I just play it safe, and use 30 or higher toggles.
also, could someone enlighten me as to what exactly a relay does? any links for a elctrical simpleton?

 

[XSLeo]

A relay is a switch with high rated contacts to carry a heavy load that is turned on/off by a low current coil. Like a starter solenoid on a car. The wires from the battery to the key switch are small and can't carry the current needed by the starter. Starter current is carried by the heavy cables with the solenoid's heavy contacts to carry the current and the key switch turns the solenoid on/off.
Leo

 

[jurand]

could someone enlighten me as to what exactly a relay does?

automotive relay has usually four contacts two small amperage and two high amperage. I will explain this using starter solenoid (relay), look on the pic below. Switch in the rectangle is your starter switch - closing starter switch you add juice to solenoid built-in into relay and force connecting of two main contacts so higher amperage may power your light/starter motor/something else. amperage flowing through solenoid and starter switch is very small so your switch can be small with tiny connectors/wires but main contacts in the relay can handle more amps.

 

[CDNTX650]

i used a relay on the scratch wire harness for my 74. 18 awg to main key and toggle, then wired with 10awg from the battery to the relay, then relay to fuse block. I always use relays. but thats the electrician by trade showing through.

 

[angus67]

hmph....thanks guys.