The Earnhardt Starter Switch (abandon starter relay?-continued)

[TrueAce]

Sooo.......since my photo posting skills are limited, here is a continuation of the "abandon starter relay" post, I'll try to show you what I came up with. First, A few months back I was wanting input on eliminating the bulky handlebar switches. Here is a couple of shots that show just that.......the ignition, kill switch, starter switch and light switch are moved to left side of the relay box, next to the fuse box,above the coils. The green lighted switch is "Ignition", connected to +12 at the battery and ground, feeds to the red lighted "Kill Switch", which feeds to "Brass Starter Button", which is directly wired to Starter. And it works! Appropriate gauge wire, in-line fuse, and NO STARTER RELAY! Surely I am doing something wrong......come on guys and lay it on...........I expect at least three "Yes, but......"!

[TimTyler]

Would love to see a simple schematic of the three switches wired together.

[TrueAce]

TimTyler........here is a very simpleton's wiring diagram....ain't fancy but it works. 'Course you gotta use right wire & fuse, I've run it in 16 gauge for now. After melting a few low amp switches, I got a brass automotive type, very small but carries the load.
The flimsy stock starter switch/kill switch is amazing . First time I just relocated the whole switch unit, but was uncomfortable with the contacts & thin wiring, so began experimenting. The lights are direct wired to the battery through switch & small relay,too.
And ,yes, Robert, I have "defeated" those dubious BMW safety features, but I think this starter wiring eliminates a major issue in the starter relay. I understand about "small current triggers large current through the relay coil", but the reliability of the Bosch stater relay, not to mention the expense, is unacceptable. How come TimTyler had to "bonk" his starter relay successive times during his trip? Not acceptable. Surely somebody has devised a more elegant solution in modern times.

[TimTyler]

Thanks!

So why do you need a kill switch?

[TrueAce]

Well, cause bikes have kill switches? I was hiding it since the key switch was eliminated, but then placed where I could reach it. Got starter relay OCD, and figured more switches mean  "confusion to the enemy". But then again, so who will want to steal a Special K?

[Scott_]

Well, realistically speaking, where you have located the switches you have zero need for the kill switch next to the ignition switch. For your purposes of simplifying you starting circuit, you are just adding another point of failure.....

The purpose of the 'kill' switch is to have a 'very easy access' emergency function. Hence the location on the bar next to your thumb. Can be operated without having to remove you hand to operate in an "oh-shit" moment.   Just my opinion, as you asked for.



Looking at your wiring diagram, the entire starting motor current will pass thru both switches............

[rbm]

My concern too, Scott.

Also, TrueAce, you're abandoning the neutral detect circuitry as well, so hope you don't try to start the bike in gear.

[TrueAce]

You are correct, TimTyler, repetiously redundant. I'll eliminate that.
You are correct,too, RBG, and in-gear starts are verboten, will be careful.
So now, do you see any need for the load shed relay? Lights aren't in the circuit anymore.
Lest anyone feel I'm desecrating a cherished K100.........This bike was headed to the junk yard after a hard life, so it is a project. My very special Dakar Yellow K5S5 will never be modified!
Thanks for all the feed-back, guys.

[Scud]

Press on with the project - make it yours and "desecrate" away...

I just want to reinforce the value of of a kill switch on the handle bar. Especially if your ignition switch is also not in easy reach. Chances are slim that you will need it, though. If you don't want it on the bars, may as well get rid of it altogether - so it's a calculated risk, sort of like motorcycling in general.

With no keyed ignition switch, I suppose your "key" could be a fuse for those times that you want to leave the motorcycle unattended.

On the starter relay: I noticed that my 1992 relays are different than the ones in the 1990 bike I got for parts. Is the starter relay problem more common on the older or newer bikes - or is there no difference?

[Scott_]

Re the load shed relay.
The purpose of it is just that, to shed un-necessary current load so that the most battery capacity is available to drive the starter motor.
Just like in your car/truck.

[TrueAce]

Thanks,Scud, 10-4 on the kill switch. Don't know about later K's, this one is 1985 100RS and just spits them out. I did try an identical NAPA relay a couple times, but no joy. Think I'll pull the kill switch from the circuit, run it to the handle bar, and hide a battery cut-off to foil the thieves....at least slow them down on the start protocol. Stopped to try to help a custom chopper guy at Home Depot get his bike started last week......he forgot where the hidden kill switch was. Must have been the fumes or something.

[TrueAce]

Yes,Scott, my point exactly. If it ain't in the starter circuit there nothing to shed, just more weight!

[Scott_]

It's not about being "in the starter circuit"(or a weight issue) it's about the current capacity of the battery to turn over the engine.  These K-bike batteries are only in the 18-20AH 275a cca rating to begin with.
If the battery is spending 5 amps of current to keep the headlight lit, that is 5 less amps available to the starter.  Just sayin.

You being down in Florida, it may not be quite as critical there as it is up in the north during the colder months.

[TimTyler]

My bike has tipped over into a ditch once or twice in remote locations. I was glad to have been able to access the kill switch on the handlebars.

[TimTyler]

I'm looking at your schematic and I'm still confused. Your switch array seems to just control the starter.

What have you done with the actual ignition connections from the original keyed ignition switch? Those need to be connected when the bike runs and disconnected when the bike is off.

[TrueAce]

Right, I did not show on the diagram the existing wiring to the FI relay, Motronic, etc., which is all intact and circuits tested. Just a quick response to show by-passing the starter relay.

[TrueAce]

Scott, my load shed relay comment about "weight" was tongue-in-cheek...........since the starter is direct wired, and the same for the lights on a different circuit, there is no function for the load shed relay. And, yes, after activating the starter, I better remember to activate the lights. That switch is at the top of the stack and lights as well, so three lights on three switches and good-to-go! Why go to all this trouble? The handlebar switches were all junked up when I got the bike, and I got curious about what I could come up with. Too much time on my hands, but it keeps me off the streets at night!