Author Topic: K 1 starter switch  (Read 938 times)

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Offline beemerbum

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K 1 starter switch
« on: January 29, 2018, 08:27:16 pm »
I got a K1 750 that is missing the starter button. I have purchased a new button as well as the minuscule brass spring for it. What I lack is how it goes together. Does anyone have a diagram of the guts of the unit or a photo? I understand that pushing the button grounds the circuit to the handlebar and the starter spins. Is there a part between the button and the handlebar?

Offline Yamahawk

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Re: K 1 starter switch
« Reply #1 on: January 30, 2018, 03:38:08 am »
There may or may not be a ground wire, that completes the circuit to ground. The early start buttons were different than the later ones, the Y/R wire is grounded when pushing the button, and may just make contact with the housing, which is grounded by clamping it to the handlebar, but not too sure on that one. The later models have the Y/R wire and a G/R wire that go back to the solenoid. They are connected when the button is pushed. I have an old K1 right hand control in the workshop, I will go out and look at it later. I rewired my K1 with a K4 harness, and updated the handlebar switches to the later ones also, with an on/off switch for the headlight.
Charlie
1971 CB750K1 (newest bike), 1996 Royal Enfield 500 Bullet (therapy bike), 1981 Yamaha XV920RH, 2006 Kawasaki Concours (retirement bike), 1975 Yamaha RD350 (race bike), 1989 Honda VTR250 Interceptor (race bike), 1986 Kawasaki EX250 Ninja (race bike in progress), 1985 Honda Elite CH250, 1973 Yamaha GT1 80cc, 1974 Yamaha DT360 project bike.

The Only Thing Necessary for Evil to Triumph, is for Good Men to do Nothing.
Edmund Burke

All Things work together for good, for those who love God and are the Called according to His purpose.
Romans 8:28

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Offline beemerbum

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Re: K 1 starter switch
« Reply #2 on: January 30, 2018, 07:18:00 am »
Thanks for the info. Please let me know what you find in the K1 unit. Since the K1 was the most produced model, this is likely not an uncommon situation


Offline Kevin D

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Re: K 1 starter switch
« Reply #3 on: January 30, 2018, 09:30:18 am »
I didn't see a dark green ground in the rh switch anywhere, pretty sure the button takes the yellow/red? solenoid  wire to the switch housing>handlebar>triple tree>steering bearings>frame>harness ground+battery ground.

This cool WD needs some Adobe to run:

http://oldmanhonda.com/MC/wiring750K1.html
71 CB750 K1
103,000 miles
Original Owner
———past———
70 SL100/125/150
70 Candy BlueGreen CB 750 K0
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Former Honda parts kid/counter kid/do all
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Offline Yamahawk

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Re: K 1 starter switch
« Reply #4 on: January 30, 2018, 10:55:46 am »
Here are some pics of the start button. There is a thin post that protrudes through the small hole in the bracket that screws down to hold the switch together, and the spring keeps it from touching the copper pad that attaches to the green wire. When you push the button, it makes contact with the small square that has the wire on it.
Charlie
1971 CB750K1 (newest bike), 1996 Royal Enfield 500 Bullet (therapy bike), 1981 Yamaha XV920RH, 2006 Kawasaki Concours (retirement bike), 1975 Yamaha RD350 (race bike), 1989 Honda VTR250 Interceptor (race bike), 1986 Kawasaki EX250 Ninja (race bike in progress), 1985 Honda Elite CH250, 1973 Yamaha GT1 80cc, 1974 Yamaha DT360 project bike.

The Only Thing Necessary for Evil to Triumph, is for Good Men to do Nothing.
Edmund Burke

All Things work together for good, for those who love God and are the Called according to His purpose.
Romans 8:28

Though He slay me, Yet will I trust Him...
Job 13:15
will you trust Him...?

Offline Yamahawk

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Re: K 1 starter switch
« Reply #5 on: January 30, 2018, 10:59:12 am »
I didn't see a dark green ground in the rh switch anywhere, pretty sure the button takes the yellow/red? solenoid  wire to the switch housing>handlebar>triple tree>steering bearings>frame>harness ground+battery ground.

This cool WD needs some Adobe to run:

http://oldmanhonda.com/MC/wiring750K1.html
Yes in the schematic it does for the K1. The later models have both wires. Now, in my switch, someone had replaced the Y/R wire with a green one, but same scenario. It grounds through the right angle tab to ground on the handlebar/switch housing.
harlie
1971 CB750K1 (newest bike), 1996 Royal Enfield 500 Bullet (therapy bike), 1981 Yamaha XV920RH, 2006 Kawasaki Concours (retirement bike), 1975 Yamaha RD350 (race bike), 1989 Honda VTR250 Interceptor (race bike), 1986 Kawasaki EX250 Ninja (race bike in progress), 1985 Honda Elite CH250, 1973 Yamaha GT1 80cc, 1974 Yamaha DT360 project bike.

The Only Thing Necessary for Evil to Triumph, is for Good Men to do Nothing.
Edmund Burke

All Things work together for good, for those who love God and are the Called according to His purpose.
Romans 8:28

Though He slay me, Yet will I trust Him...
Job 13:15
will you trust Him...?

Offline beemerbum

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Re: K 1 starter switch
« Reply #6 on: January 30, 2018, 12:36:19 pm »
That is precisely what I need to see!! Thank you very much!

Offline beemerbum

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Re: K 1 starter switch
« Reply #7 on: January 30, 2018, 04:42:23 pm »
If you would allow another question. It seems that the piece to which the green wire is attached would have to be removed to insert the new button and spring. How else can the button and spring be inserted into the housing? Before I pull oil something, I would like to be sure. Thanks in advance

Offline Yamahawk

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Re: K 1 starter switch
« Reply #8 on: January 30, 2018, 05:59:57 pm »
If you would allow another question. It seems that the piece to which the green wire is attached would have to be removed to insert the new button and spring. How else can the button and spring be inserted into the housing? Before I pull oil something, I would like to be sure. Thanks in advance
It looks pretty tricky! I think it will take several failed attempts to get that pin/spring into that little hole in the tab. But, a set of hemostats or tweezers may help you hold the small bracket and slide the tab between the spring and the terminal/pin. I lost the spring it fell onto my floor, and didn't have time to look for it, but it was an old housing, and pretty rashed out. So, I had already replaced it with a new one! That's an option as they can be found for under $50 complete with harness.
Charlie
1971 CB750K1 (newest bike), 1996 Royal Enfield 500 Bullet (therapy bike), 1981 Yamaha XV920RH, 2006 Kawasaki Concours (retirement bike), 1975 Yamaha RD350 (race bike), 1989 Honda VTR250 Interceptor (race bike), 1986 Kawasaki EX250 Ninja (race bike in progress), 1985 Honda Elite CH250, 1973 Yamaha GT1 80cc, 1974 Yamaha DT360 project bike.

The Only Thing Necessary for Evil to Triumph, is for Good Men to do Nothing.
Edmund Burke

All Things work together for good, for those who love God and are the Called according to His purpose.
Romans 8:28

Though He slay me, Yet will I trust Him...
Job 13:15
will you trust Him...?