TOPIC:

I have a 1977 kz750. It's fairly new to me and has its share of issues from sitting too long. But everything has been going well till two nights ago. Was riding and bike totally shut off. Ended up pushing it 30 blocks to my closest friends house to store it till I could grab my truck, crappy night. 

after getting it home I started going through it and it appears the ignition switch is done after 45yrs. Jump around the switch and everything seems to work fine, bike kicks right over. 

New switch is on the way already. I've recently upgraded my headlight to an led unit that has a wattage of 45w/75w. I was not running the high beam at all.

Could this have caused the ignition switch failure or just bad timing due to age? Don't want to ruin another switch. 

Obviously can and will run a set of relays but not sure where to put them on the bike still and just trying to understand why something broke on my bike. Thanks for any help 

After doing some quick math the stock light pulls 2.91A and 4.16A

My Led headlight pulls 3.75A and 6.25A

All of these currents should be capable of being run on 16-14ga wiring over this short of a distance. My relay setup will use 12ga just to be sure. 

I would think these levels of current wouldn't be responsible for the switch failure but i don't know. Hope it's just the switches age but don't want to be stranded again 

If the bike was stored outside for a long time i would not be surprised if all the switch gear had degraded some. The bike is 45 years old at this point, i doubt the headlight would have damaged it as long as you are still using the headlight fuse.

On a semi-related note - have you checked to see if you are getting full voltage to your coils? If your kill switch has degraded it likely is not passing full voltage to the coils. a popular mod on here is the "wired george coil mod" where in you use the kill switch to activate a relay that draws straight from the battery (use an inline fuse). it has made a noticable difference in startup on every bike i have done it to.

I don't know that it was stored outside long term but the previous owner did it no favors. 

I also didn't think the headlight would have caused the issue but had to confirm that. I'm sure it's just age, not surprised at all. 

And thanks for the mod suggestion I will look it up, not sure how helpful it will be, my bike is kick only so I don't need a ton of power on startup.

And the previous owner disabled the kill switch for some reason, so I've just been turning it off with the ignition until I get around to replacing the controls with more modern replacements this winter. 

Here is the link:

wgcarbs.com/index.php/using-joomla/exten...-categories/89-COILS

This will put more power to the coils for easier starts and better ignition performance.

Ignition switches do age and sometimes die from old age. Mine did  5 - 10 years ago.  I knew there was a voltage drop across it and then one evening  the bike just died at a traffic light. No lights, nothing. I got it started again by jiggling the key and with the proper use of swear words but that was it. Bought a replacement Emgo switch. The internal contacts wear and the solder degrades. Some switchs may be restorable but mine was not. I opened the old one up. It was pretty bad inside.

Ok so all I did was unplug the igntiojnswitches connector at the headlight bucket and plug it back in and now the switch works again. Faulty switch? Just dirty connections? 

Faulty switch or dirty connections? You will have to be the judge of that.

By all means clean the connections (Deoxit D5 is good) but while you are in there have a good look at the harness side of the connector block and at a wiring diagram and you can probably quickly figure out how to hotwire if the  problem happens again. Might save you pushing 30 blocks. 

in first post you mentioned you have a replacement switch on the way. If it were me I would install the replacement. You can probably use the new key in the gas cap and the old one for the seat lock. Not a major inconvenience in the grand scheme of things.

Definitely still going to replace it when my z1 shipment comes in. Just curious cause if it's connections I will save this factory switch as a back up. 

UPDATE PROBLEM SOLVED 

Turns out the entire problem I was experiencing traced back to poor connections at the fuses themselves. Fuses were warm so I checked resistance and well that was the problem. Cut out the old fuse holders and wired up new blade fuse holders and the problem hasn't resurfaced.