Hello, new to the cb750 world, diving in and would like some electrical help.

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AcesAndEights

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First of all I'd like to say hi, my name is Rick, and I'm an addict. I really enjoy these old motorcycles though I've been lucky enough over the last three years to skirt heavy electrical issues. I started riding when I was 17, and shifted my weight to older model bikes over the years. This is my fourth bike, yet I've always preferred the older models. Kz650 was my first true love and now I've moved on to the CB750.

Anyway, here we are. My woes are simple, due to vibration and age the right control housing cracked and made tightening the throttle impossible. Bought a new throttle housing, cables, yada yada. Decided it was time to get rid of the bulk and go more "simple." I want to get rid of the on/off kill switch, button starter and headlight switch which requires some hard wiring. looking for advice.

Already pulled off the headlamp, next I plan on twisting the solid black wire and black/white stripe wire together and trying to get the bike to start. Probably much more complicated than this, but hey, this is how we learn.

As a heads up, the bike is in perfect running condition outside of what I'm about to do to it. Working with a '75 cb750

Obligatory photo, always wanted to ride on Christmas.

cb750christmas.jpg
 
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My plan is to make it kick start only. I'll leave some of the wire capped off in the headlight apposed to removing it entirely, just incase later I'd like to restore it.
 
Keep in mind the 750 kickstart setup was meant as a backup to the electric start. Yes people just kickstart them all the time but the kickstart setup is not a bullet proof setup on these. The kick shaft rides in just a plain aluminum side cover and will wear oblong over time. If you go to a big bore later on the shafts can break, if you are staying stock it will be ok. They used to make upgraded shafts back in the day but not anymore. The return spring will also break over time from repeated use and only way to replace it is to split the case. I have seen a broke spring in a stock motor, not sure of the history of the bike though. Its up to you but the electric start works so well on these motors and the kickstart will get old very fast especially when you start running into carb and/or ignition issues in the future.
 
This bike is probably the best running machine I've ever sat on. The guy who owned it previously was a carburetor magician. He even taught me how to rebuild/sync my old KZ's carbs. I don't foresee any issues with the Honda anytime soon. Also looking to keep the engine stock. It's such a champion, I'd feel bad cracking her open. I will be replacing the clutch though. So outside some basic electrical work and some cosmetic doo-dads I think I'm ok with just kick starting it for awhile. Dirt, you are absolutely right, it will get old fast.. When that happens, I look forward to a turn key starting system. But that won't be for a year or so.

I believe the Off/On/Off switch is a black/white wire(ground?) and a solid black wire(hot?). With these two together the bike should start right up. Or will I need to complete the circuit with the head lamp switch and headlamp plug too?
 
You will have to keep up with the maintenance of the points (adjust, clean/or replace) or you will have hard start issues in the future. The points and timing need to be checked often....they do wear fairly fast on the 750. Unless you go with an electronic ignition. When the timing starts to get off you will get a kick in the leg from the kickstarter.
 
Ah-Ha! Yes! I was actually going to post later on about electronic ignitions. I saw one on the CycleX forum that was crazy pricey, yet seemed to get the job done. Is there much fabrication work worth installing an electronic ignition system? And of course, if you recommend a specific brand I'd happily look into it. Keep in mind I'm trying to keep a stock engine/carbs. Doubt I'll change the exhaust any time soon.
 
The Cycle X ignition is the most expensive one for the 750's but it is also the most accurate as far as timing goes. I run the Dyna ignition setups on mine. No fabrication work need for these they just bolt in in place of the points and replace the stock coils. Lot of people use the Pamco setup but I dont like design of them. Do a search on this site, it has been discussed more in depth a couple of different times.
 
Sorry about the late updates, been a really busy ass week at work. Just got around to trying to bypass the off/on/off switch. Ran into a slight problem, the headlight switch. My plan is to rig a bomber-esque switch at the center of the handle bars (triple tree area) and use that for the headlight high/low beams. Basically the colors are a bit wonky here. There is a brown wire/white stripe and a solid black wire coming out of the right control for the headlight on/off. But in the lamp bucket, there is only a single spare black wire, and I used that to bypass the off/on/off switch.

Any suggestions dirtdigger?
 
looks like you are up late too. dunno if this will help you any,,it is a basic wiring diagram. i have always found it easier to just rewire the whole bike and add any extras or fuses that you want. it looks way more complicated than it is but it is really simple. in the end you only have a handful of wires and you will know where any malfunction is likely to be.
Edit,,just click the image it should get bigger. good luck.
simple_wiring_diagram.jpg

when i dont use a handlebar switch i always have just used two toggles. a two way on/off switch with the black power wire on one side and then a jumper wire from the other side to the other toggle which is a three way,put your wire from the two way on the middle post of it and at either end the lo and hi beam wires from the headlite plug. the green from the headlite plug is grounded. this will not work with just the three way switch though. the first one basically turns the headlite on and off and the the other switch does the hi /lo
 
I don't think I'm ready for a whole rewiring, as fun as it sounds. Maybe later on when I upgrading to a solid state ignition? That seems like a good thing to do all at once.

Here are a few pictures of the switch I found. I'm thinking of putting it under the gas tank somewhere along the frame. Was planning on reusing the left over wiring from the right hand controls. Currently keeping this simple, On/Off switch for the head light. Should work out just fine. After this guy is hooked up I'm planning on starting the bike. Should be tomorrow morning (gotta go back to work).

the side of the switch says:

10A 277 VAC
20A 125 VAC
1 1/2HP125-250

I'm assuming this is the rating for the amps you can push through the switch?

OnOffSwitch1.jpgOnOffSwitch2.jpgOnOffSwitch3.jpg

The wires I'll be using and brown/white stripe and black.
 
Wicked, worked first try. I'll be back on the road tomorrow with some luck. Just need to buy lube for the new throttle cables.

Now I'm not sure how I'll be fastening the switch onto the bike perminently, so any suggestions there are welcome. I'm putting it under the gas tank for now..With a lot of electrical tape...
 
you have both hi and lo beam? too cool,i have never been able to get anything like that to work for both beams,,it was always stuck on one or the other,that is why i used the two switch setup. apprentely i have been using the wrong switch on some bikes in the past. i gave up and started using those universal chinese hi/lo/horn/turn signal ones for the handlebars on e bay along with a relay to make up for the smaller gauge wiring they have.

before the tape on yours try a tie wrap in the clear area to hold it to the frame bar, then tape the crap out of it. if it works its all good.
 
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I left the High/Low beam alone. I thought it best not to mess with it as it seemed complicated. When I go to replace the left hand side I'll do something fun then.

Thanks for the suggestion, I'll wire tie it, tape it, then put a nice metallic clamp over it once I'm all done.
 

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