Starter solenoid as a relay

[Anonymous]

Guys,

Can I use a Starter Solenoid as a relay for my coils?

I don't have a spare relay, but I have a spare 12v Solenoid.

Is there a problem using a solenoid for extended periods? Or am I just being cheap & lazy? :P

Thanks!

[IanFrancisco]

Forgive me for being a little nosy, curious and ignorant all at the same time. Why do the coils need a relay? I think your bike has standard points/condenser ignition. The only circuit(s) that draw enough current to warrant a relay are the starter (obviously) and possibly the headlight, if you're running a 100W H4 bulb. Some guys have speculated that the OE headlight switch wouldn't hold up to the current draw of a 100W bulb and thought a relay would be a good idea in that case. I suppose a starter relay could be used to switch current to the coils but I would worry that it would be intermittent and be one more possible point of failure in the ignition circuit.

[Pete Logan]

Why do the coils need a relay?

They don't.

Good question, though

Pete

PS: I just noticed Patrick is Canadian. That might be relevant.

[Anonymous]

I know that they don't NEED a relay...

I would just like to connect a direct link to the coils from my battery since I appear to be losing 1 volt at my coils.

I've read some threads here where some people have done this. I just would like to know how efficient a solenoid relay is for this purpose.

I wish I could think of a snappy comeback on the Canadian thingy... :P

[FTGRET]

Starter solenoids are designed for intermitant use, not continuous duty. If you feel that you need to use a relay, any of the ones sold for foglights will work.

[Pete Logan]

I wish I could think of a snappy comeback on the Canadian thingy... :P

Sorry, I just had a rush of blood to the head cos we got the Ashes back

Got family in Canada.

Pete

[Anonymous]

Thanks Gary... your post reminded me that I have an unused set of IPF fog-lights with a 25amp relay.

I've just started to rewire the coil power-supply. I'll let you all know how it turns out. So far, so good.

While I was doing this, I also found some corroded wiring from the points to junction point near the battery. Looks like I'll be replacing that as well. I tried a temporay rewire to bypass that wiring but I was still under 12 volts at the coils.

Cheers!

[focus frenzy]

if you do a bit of tracing you will more than likly find that the ignition switch is the culprit of your voltage loss.

power has to go through the main fuse then up to the ignition switch, it then comes back and splits off through the differant fuses before heading back up to the kill switch then back down to the coils.

[Anonymous]

Yeah, I tried to see what was messing up the voltage. When I probed the Kill switch (on, no continuity) I have my full 12.7 volts. As soon as I flip it, I lose one volt.

I tried to check resistance from every point to and from the switch and it looks fine.

The kill switch on my bike does't look like it can be disasembled so I tried my best to clean it with contact cleaner and then I lubed it withe dielectric grease. It still didn't help.

The best thing that's helped so far was replacing the connectors on coils-to-points ground wiring. I gained about .25 volts when doing that. I will completely redo that wiring soon and see what gains I get.

[Anonymous]

Well... I hooked it all up with my spare relay.

Everything looks to work well, the coils are powered (with 12 volts!) and I get a nice spark on the plugs... Not sure if it's "fat", but it's blue.

I also replaced the points to junction grounding wires, so I could be super clean on all my coil points, I think.

I'll take it out for a spin tomorrow and see if it helps my sooty/rich problem.

Cheers!