78 Standard 3 wire Ignition. 4 Wire Replacement Question

[LVTom]

Hi Folks, I have a 78 Standard that I lost the Ignition key for. No biggy I have another ignition switch in the garage. The 78 Iginition has a blue wire, a tan wire and a red wire. The newer switch has a tan, a red, a blue and a blue and red. I think I know the answer, but please read on because I have a bigger question. Question one, can I splice the blue and the blue and red together and then use the old connector. Question two. What size fuse should the ignition swich have? Thanks for your time. Tom
Trou

[psycoreefer]

The ignition switch should be fussed with the 30amp main fuse, it doesn't need any other fuses.

Just ignore the extra blue/red, it is a power wire for the 4-way flashers, if your bike doesn't have them, you don't need it, just protect the end so it can't short out on anything and leave it loose (or take the switch apart and un-solder it if you want). Connect the other wires as they were on the old switch. I've not got a wiring diagram in front of me but I think if you splice the blue and blue-red wires together it would cause your tail lights to be on all the time, because blue-red is hot always for the 4-way flashers.

[CatatonicBug]

If the only reason for swapping the switches is a lost key, just take the switch to a locksmith or dealer and use the number on the bottom of the switch to get a new key made. That way, all the key locks remain the same on the bike.

[natemoen]

So 78's do not have hazards at all? How would you put hazards on a 78 or cant you

[DGXSER]

OK, as to the switch and wiring, an easy solution is to pull the two screws holding the black plastic potion to the metal locking housing on both switches, then simply swap the wiring and the black plastic piece they attach to. Very simple switch. Long story really, but I just did this twice.

To add hazards to the bike, you at a minimum would need to add a hazard flasher relay, and swap the left switch with one form a later model bike that has them. But there would be some wiring involved as well as your harness is not prepped for them.

[DGXSER]

Pictures are worth a thousand words

And I suck at describing stuff in words, I'm an engineer dang it, I draw stuff.

Anyway, here are some pics to go with what I was describing.

Here is the stock three wire ignition or key switch...you will want to remove the two screws on that small metal plate and remove it.....



Next remove the two screws shown here and gently pull the black plastic section from the metal locking housing, note that when you do the mtal block you see in the end hole of th emetal housing through that opening you removed the plate from, will try to fly out that opening, so keep pressure against it with your finger as you pull the black part off....



Next you see this in the end of the switch, note the orientation of the white plastic fork lock assy, it needs to go back on in the same orientation and it could go on in 180 deg out....



once you pull that white lock piece off, the wiring and its contact plate pull right out, so get to this point on both locks and switch the wiring and contact plates to change a three wire switch to a four wire switch......



The rest of what you see including the rotating contact buttons are the same between a three and four wire switch......



If you find a switch is bad or broken like I did and want to swap the actual key switch out between two switch assy, when you get down to just the key cylinder in the housing, look inside the housing at the end of the cylinder and you will see a small copper stub sticking up. It is spring loaded, and you can take a small screwdriver and push it into the lock cylinder and it will push out of the housing, but have a key in the switch when you do this or the tumblers could fly out.

Ohhh...and throughout the disassembly of the switch, take not of orientation of everything including that lock cylinder, it becomes real important to get all the key functions when put back together. DAMHIKIJK

HTH

[LVTom]

Thanks for the help

I just wanted to thank you guys for the help. I installed the switch and we are back to good. I've had three different keys for awhile so I will probably give Andreas a shout and replace the ignition, gas cap, helmet lock and side cover lock. Thanks again, you proved that this is a great site. Tom