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Keyswitch Power

tadd442

CB750 Enthusiast
Messages
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Points
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Location
New Richmond,Wi.
I hear that EMGO keyswitches actually only allow 7-8 volts instead of 14 as Honda intended and will burn out in time. Anyone else hear of this? How can I check my switch?
 
With only 7-8 volts i dont think the bike would run or any accessories operate. You could check voltage in and out of the switch and see what reading you get. The quality of the contacts would determine the longevity of the switch
 
The bike will run on 7-8 if you are running points, they take far less voltage than electonic ignition. I dont know why they would reduce voltage but just check with a voltmeter and see what the voltage is coming out of the switch. Or check voltages at lights and to the coils.
 
I have seen contacts become resistive from arcing and carbon build up on them. Usually have intermittent problems beforehand. Dont know what kind of quality those are. I have never used aftermarket switch. I have always used a push-pull switch for cars,it confuses most people because they are looking for a key slot. Not theft proof but most think it is my choke knob,as it is mounted next to my speedo
 
The bike will run on 7-8 if you are running points, they take far less voltage than electonic ignition. I dont know why they would reduce voltage but just check with a voltmeter and see what the voltage is coming out of the switch. Or check voltages at lights and to the coils.

I see...the switch would act like a "regulator"
 
I should add that it IS a points bike. I'm looking to replace the switch on my K-1 with a new one from CB750 Supply dot com and they won't disclose the manufacturer name. They also say they do not have any specs on it.
 
I would try it with how cheap it is and see how it works I'm sure it will work ok. The switch should let full battery voltage pass through, if it drops voltage then you have a problem with the switch.
 
I would try it with how cheap it is and see how it works I'm sure it will work ok. The switch should let full battery voltage pass through, if it drops voltage then you have a problem with the switch.

I am trying to avoid scratching my head a few years down the road when the 7-8 volt switch malfunctions, and I can't figure out why power isn't correct after I have replaced every wire on the bike. Maybe I'll just go a different route?
 
I have had this switch on my bike over 20 years without an issue.you could conceal the switch, in a inconspicuous place, but i figure the best place to hide something is in plain view. Contacts tend to act like a resistor when bad, it shouldn't be a problem with the lower voltage on a bike as compared to household voltages.the only reason i changed mine was the key was broken off inside. Have you tried e-bay or other members on here for a replacement ?
 
tadd, lets start over. Are you having a voltage issue on this bike?? I thought you where just asking about a certain brand switch and if they are any good.
 
dirtdigger, Not that I am aware of. I am in the process of gathering pieces to bring her back to life and as of yet, I haven't fired it up. It looks like it will be a while before I even could try. That being said, you are correct in your understanding of my initial post. One thing I am particular of is wiring...I despise problem solving regarding it and would like to only deal with it once. Knowing it will be some time before I can utilize the parts that I would purchase now, I'm sure I would exceed any window available to return a faulty product. (If there even IS a vendor allowing the return of ANY electrical component) I am thinking that an OEM piece is in order for my best chance of success in the long term. Another member here has told me that an EMGO switch, though it says it will work for CB750's, is made to fit too many other bikes and has a lesser voltage rating. He also says that it will work initially, but in time will burn out causing ??? later.
 
The switch should pass the voltage no problem if it's new.. It's not like it's designed to limit the voltage. After the switch wears out you might have problems, but I can't see it not working when new unless you happened to get a bad one. Hook it up to a good battery, get out your multimeter and see what voltage the switch is allowing through it. You could also check the resistance of the circuit to see if there are any connection problems.
 
sohc4shop.com sells a product to take care of this problem. The guy who runs the site is Hondaman on forums.sohc4.net. His product has a nice writeup on the situation http://sohc4shop.com/catalog/product_info.php?cPath=23&products_id=49

I would think a standard 30 amp automotive relay would work here. From the picture it looks like a $5 relay with some wires attached.

This is what I was talking about!
Thanks, grepper! I was just about to have my buddy get involved to clarify.
 
That kind of sucks. Sounds like the wiring and contacts are just undersized in that switch when used on the CB750. The relay trick would work I guess. Same thing people do for headlights being controlled by small switches. Maybe you could find a better switch that would work and not have to mess with the relay.
 
I would still do the Hondaman fix, then that will be the last switch you will ever have to buy. Hondaman knows his 750's and I HIGHLY recommend his book, it is better than any shop manual on the market. It is a little expensive but it is a quality book with a lot of tips and tricks he learned as a Honda mechanic.
 
Yeah but a switch that can handle the current will last a really long time too. The relay is just as likely to go out in time, although cheap and easy to replace. Plus adding a relay means more wiring. Just some things to think about.
 
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