Topic: Start button relay?

[budman]

I've recently begun a restomod on a CB750K4.  I'm getting way ahead of myself, but it's probably never too early to start thinking about this stuff.  I've been working on the wiring diagram for the bike.  I want to use some low amperage push button switches for the start button, the horn button and a kill button.  I know I'll have to use relays with the horn and kill buttons.  I'm currently using one of these switches with a relay for the horn on my v-twin and have had no issues with it.  These switches are tiny and have a very thin gauge wire.  As far as the start button goes on the CB750 I'm wondering if I should install a relay ahead of the solenoid.  I know it's redundant.  I'm just afraid I might burn up the switch.  Any down side to adding a relay ahead of the solenoid?

[zeech]

The switch is so momentary I don't think you're going to have an issue, I've run 16ga for a while. All you need is a grounded switch (bare metal like a handle bar) with a single wire going to your solenoid to trigger it.

Probably no downside to it. I usually error on less stuff but should probably do more. Oh well.

[Bodi]

The solenoid coil gives a healthy inductive kickback on disconnect, I would add a diode (1N4004 or such) backwards across the switch contacts to avoid arcing and damage to a small switch.

[budman]

The solenoid coil gives a healthy inductive kickback on disconnect, I would add a diode (1N4004 or such) backwards across the switch contacts to avoid arcing and damage to a small switch.

Good idea.

I'll probably post the diagram soon to get some feedback.

[budman]

Here's a preliminary wiring diagram.  It has a start button relay before the solenoid.  I found a couple of automotive diagrams with the same relay and solenoid setup.  I think the switches I plan on using come prewired with something like 20 or 22 gauge wire.  That's the reason for the relay.  I want to avoid a potential burned up switch.

Looking for feedback.