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Kill switch/throttle control 75 CB500T

Bschuler

Well-known Member
Joined
May 18, 2023
Total Posts
53
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0
Location
Topeka, Kansas, USA
Ive been trying to find a new killswitch for my 75 CB500T, but due to my lack of experience and knowledge im alittle lost, ive found ones that look similar on both amazon and ebay, but im unsure of the wiring, and i also found one on commonmotor but theirs have some headlight switch thing in it. Any ideas or part numbers any suggests?
 
This is one of the parts for the 500T that is difficult to find, in part because the change to full-time headlights happened around the time the 500T was sold and in part because they only sold the 500T for 2 years. If you buy the one from CMC and follow their wiring diagram you can make that one work, and you'll be able to turn off the headlight when you want to. In this situation, Common Motor offers one of the simpler alternatives despite the switch being a reproduction piece coming from who knows where for $70. What they don't explain to you is this switch is designed for a push-pull throttle cable setup like the CB360 uses (both carbs connected together on a mounting plate) and yours only uses a pull cable, so there will be an open hole in the bottom of the switch under the headlight on-off button where the return cable would be on a 360 or a 4 cylinder with similar setup.

Unfortunately, unless you want to spend ridiculous money for the few 35130-375-671 switch assemblies available on eBay, this is your least expensive alternative that is similar to original.
 
Thanks for the quick response, I’ll probably have to buy the one off of common motor, since the cmc one is out of stock, maybe i can find a way to cover that bottom hole if it bothers me too much
 
Bschuler said:
Thanks for the quick response, I’ll probably have to buy the one off of common motor, since the cmc one is out of stock, maybe i can find a way to cover that bottom hole if it bothers me too much
Click to expand...

By CMC I meant Common Motor Collective, I just hate saying their name out loud to often because their mostly hideous approach to maintenance on these bikes mostly disgusts me and their high markup on the same parts everyone else sells does as well.

I suspect that's what the unexplained delrin plug in their ad is for, plugging the unnecessary throttle cable hole. They spend a lot of time and words describing stuff for noobs yet still somehow forget to explain the other differences in the switch while offering the plug without explanation. Despite it not being the correct switch for the bike, I'll give them credit for offering a viable alternative. It's rare that they do anything I consider viable.
 
Update

Well i purchased the killswitch from cmc and im attempting to mock it up, i noticed binding when i test the throttle and when i take the switch off i see this. Am i installing it incorrectly? Its like the switch is shaving off plastic from the tube and binding. I know i will be replacing the throttle cable. I also understand you twist the throttle backwards so i installed it for that.

Gb6idjC.jpg
 
It seems that the new switch might not be as deep as required for the 500T throttle pipe to rotate inside it without rubbing. Wonder just how many of these they've actually installed themselves. The only thing I can think of that you might be able to adjust is the depth of the elbow for the throttle cable, if you screwed it in until there was just enough threads to hold the lock nut it shouldn't rub but if that's what is causing the problem, you could unscrew the elbow a turn or two and see if it helps.
 
Well, either im not putting this together right or its the wrong part. I tried adjustment the nut out some more but it seems the killswitch itself needs to be modified, i took some pictures to kind of show, also took a picture of the original thats broken, any guidance?
The first picture is the new one, it seems the groove for the throttle tube is supposed to be hollowed out, but is not

KHiHihl.jpg


7BFBKbT.jpg
 
Last edited by a moderator:
Hard to be sure just based on the pictures, but it seems the rear (return) cable opening height might be what is grinding away at the throttle pipe. Did you contact them to see if they have an explanation or will accept a return?
 
Bschuler said:
I havent contacted them yet, going to send them a email today and see their response
Click to expand...

BTW, next time you post an Imgur image, use the BB Code link instead of the Direct jpg link, that's how I've changed yours to display full sized. (y)
 
The crazy part of this is, the right switch he bought from CMC is also for dual cable throttle but apparently is not machined with enough clearance inside for the stock 500T throttle pipe, which seems weird to me. Since it's obviously a repop, it brings into question who they're getting them from.
 
Here's a thought. Why not swap the bottom half out? You basically use the CMC upper half with the kill switch and the bottom half from the original control?
 
76Twin said:
Here's a thought. Why not swap the bottom half out? You basically use the CMC upper half with the kill switch and the bottom half from the original control?
Click to expand...

Good idea, hopefully they mate up cleanly and then he'll have a single throttle cable lower half too.
 
Well i just got back from a short vacation and had time to inspect both parts, the bottom half is definitely completely different, kind of frustrating that they state on their website it will work but make no mention of needing to make modifications, i checked to see if i could use the lower half, which it may work, but id need to remove the wiring for the electric start as the mounting is entirely different and would need holes drilled for a ground, so im either considering returned it, or dremeling out the space for the throttle grip
 
swapping the starter button and wiring out shouldn't be hard. OR... you could just return it and source the parts needed to rebuild the control you have now.

The starter button should be fairly easy to source. You could even adapt the horn button to be a starter button. then source a used CB740 right hand control with the kill switch.
 
Hmm havent really done too much fiddling with electrical, but if i could just renove the starter button, use the bottom of the original and then wire the horn to the starter circuit. I guess that seems fairly simple.
 
Well i managed to be stubborn and used a dremel to grind the inside of the killswitch, and well, it worked, though i have a bunch of freeplay on the throttle, tried doing the barrel adjuster on the cable near the handle bar, but that didnt seem much help. Is there a adjustment on the carb i can make or does anyone know how to further remove freeplay. It’s probably simple but i never messed around with throttle cables before
 
Bschuler said:
Well i managed to be stubborn and used a dremel to grind the inside of the killswitch, and well, it worked, though i have a bunch of freeplay on the throttle, tried doing the barrel adjuster on the cable near the handle bar, but that didnt seem much help. Is there a adjustment on the carb i can make or does anyone know how to further remove freeplay. It’s probably simple but i never messed around with throttle cables before
Click to expand...

If you look at the other end of the cables where they attach to the carbs, there are adjusters on the separate cables both for taking up free movement and for synchronizing them
 
I ended up messing around with the cable at the carbs like tou said and it worked, theyre not perfect but enough for me til i get other things sorted, now onto the wiring for the killswitch, cmc gave me a diagram, but i dont think its exact, havent been able to touch it since tuesday though. Will be checking the fsm this weekend and cross checking wiring, hopefully its not too hard to find
 
Ive been looking it at work, hard to see the wire colors on a phone, hopefully on my laptop at home itll be easier to see them and i can trace out the colors and which part they power
 
Yes, the wiring diagram would be difficult viewed on a phone.

Here's a color version of the 500T wiring diagram

CB500T Wiring Color.jpg
 
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