Author Topic: Think I fried my neutral switch  (Read 1673 times)

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Offline 78whiteorbs

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Think I fried my neutral switch
« on: November 19, 2013, 08:37:52 PM »
78 Cb750F2 , was wiring up this single gauge bracket and afterwards starter button would not work nor did the gauges lights.

After hooking up my multi-meter I established that 12v was getting to the solenoid Yellow/red wiring when I pressed the starter button so button was good. I could jump the terminal post and the starter would spin so solenoid was good. After much head scratching I deduced that the other wire that goes to the solenoid , the Green/red on may not be grounding this the bike thought is was in gear and inhibiting the e -start. I ran a test wire from the green red wire to ground on the frame and the e-start works again! Now I am not sure whats up with the neutral safety wire. Guess I can just inspect it for burn out . ... What do you guys think.

The cycle X gauge bracket I was wiring up was here- http://www.cyclexchange.net/Craig%20Dash%20Board.JPG

Each indicator has a black wire and another colored ( green for neutral) . I made a mistake I believe of connecting all four blacks (hot) to a four way black connector in the bucket. Then I ran the green to the stocke pale green and red striped for the neutral . It flickered a little then nothing...need some help here fellas.thanks

Offline Frostyboy

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Re: Think I fried my neutral switch
« Reply #1 on: November 20, 2013, 02:10:14 AM »
If you have an ohm meter, there should be no resistance from the neutral switch connector & earth when in neutral & OL when in gear.
If you don't have a meter, hook up a test light to your positive battery terminal & the light probe to the switch connection. Light should be on in neutral & go out if you put it in gear.
If you don't get those results the switch is questionable.
If you connect the LG/R to earth the neutral light should come on.
Hope that helps sort it out. Cheers.
« Last Edit: November 20, 2013, 02:12:38 AM by Frostyboy »
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Re: Think I fried my neutral switch
« Reply #2 on: November 20, 2013, 04:09:42 AM »
If you have an ohm meter, there should be no resistance from the neutral switch connector & earth when in neutral & OL when in gear.If you don't have a meter, hook up a test light to your positive battery terminal & the light probe to the switch connection. Light should be on in neutral & go out if you put it in gear.
If you don't get those results the switch is questionable.
If you connect the LG/R to earth the neutral light should come on.
Hope that helps sort it out. Cheers.

Sorry but what does OL stand for?

Offline 78whiteorbs

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Re: Think I fried my neutral switch
« Reply #3 on: November 20, 2013, 05:43:40 AM »
Thanks for the reply . I'll give it a go.

Offline bjbuchanan

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Re: Think I fried my neutral switch
« Reply #4 on: November 20, 2013, 06:01:51 PM »
Green/red also interconnects with the clutch switch in the harness, just a thought. If you hooked it up wrong and saw a flicker then nothing now you might have popped it tho. Most likely not but could have happened.

Is it regular bulb or LED?
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Offline 78whiteorbs

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Re: Think I fried my neutral switch
« Reply #5 on: November 20, 2013, 07:27:19 PM »
LED.   Problem was after i got no e-start . In neutral now, the green red wire on the solenoid is not grounding. I just bypassed that by running a ground straight to battery so my e-start works again. I dont even know if it is possible to fry the neutral ground switch doing what i did....

Offline HondaMan

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Re: Think I fried my neutral switch
« Reply #6 on: November 20, 2013, 07:45:03 PM »
If you have an ohm meter, there should be no resistance from the neutral switch connector & earth when in neutral & OL when in gear.If you don't have a meter, hook up a test light to your positive battery terminal & the light probe to the switch connection. Light should be on in neutral & go out if you put it in gear.
If you don't get those results the switch is questionable.
If you connect the LG/R to earth the neutral light should come on.
Hope that helps sort it out. Cheers.

Sorry but what does OL stand for?

Think of it as a "short circuit" or 0 ohms.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

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Offline HondaMan

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Re: Think I fried my neutral switch
« Reply #7 on: November 20, 2013, 07:49:47 PM »
LED.   Problem was after i got no e-start . In neutral now, the green red wire on the solenoid is not grounding. I just bypassed that by running a ground straight to battery so my e-start works again. I dont even know if it is possible to fry the neutral ground switch doing what i did....

Not likely that you did: when the O-ring that seals the Neutral switch gets old, it shrinks a little bit. This lets the switch move upward toward the shifter drum (inside) where there is a notch: when this notch rotates around to the top of the Neutral Switch the spring inside pushes a little ball up into the notch and at the same time connects the screw terminal on that switch to the case. This is the "Grounded when in Neutral" device.

If you install a new O-ring, the switch works again. When it's old O-ring is shrunk, the switch's mounting clamp pushes the switch up about 1mm too far and the contact inside the switch body can't close, making it stay "off".

The stock O-ring is listed as 3x18mm, but I find the 3.2x18 or 3.5x18 works better, although it makes it harder to get the switch back in.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline 78whiteorbs

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Re: Think I fried my neutral switch
« Reply #8 on: November 20, 2013, 08:28:24 PM »
Well, hmmm. What the else could be the culprit I wonder.
When I was wiring up the cycle x indicator lights I connected all the four blacks from the leds inside the bucket to an empty 4 way black. This is a brand new harness too. Then when I went to hook the neutral wire the light kinda flickered. A few times and I shifted it out and into gear a few times. The light never stayed on for more than a milisecond and that is when I realized that the e start was inoperable. I also just replaced the stock key switch with a after market one . One other thing I just wired the new after market brake light as well, and here is were some sketch is: to test the running lights I was short a fuse so momentarily used a small bolt....I know,I know(it was just for a quick test though... the running lights worked fine and I shut down after a few seconds.The neutral wire on the solenoid is absolutely not grounding now though. Does that mean (and forgive me if this is a stupid question) that with my bypassing the neutral cut off switch that the neutral indicator will not work now either? I know some people purposely bypass the neutral saftey switch in  case there bike dies in higher gear they dont have to find neutral to start back up . This is a cb750 f2 btw if I didnt mention prior.
« Last Edit: November 20, 2013, 08:33:11 PM by 78whiteorbs »

Offline HondaMan

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Re: Think I fried my neutral switch
« Reply #9 on: November 20, 2013, 08:32:33 PM »
Well, hmmm. What the else could be the culprit I wonder.
When I was wiring up the cycle x indicator lights I connected all the four blacks from the leds inside the bucket to an empty 4 way black. This is a brand new harness too. Then when I went to hook the neutral wire the light kinda flickered. A few times and I shifted it out and into gear a few times. The light never stayed on for more than a milisecond and that is when I realized that the e start was inoperable. I also just replaced the stock key switch with a after market one . One other thing I just wired the new after market brake light as well, and here is were some sketch is: to test the running lights I was short a fuse so momentarily used a small bolt....I know,I know(it was just for a quick test though... the running lights worked fine and I shut down after a few seconds.The neutral wire on the solenoid is absolutely not grounding now though. Does that mean (and forgive me if this is a stupid question) that with my bypassing the neutral cut off switch that the neutral indicator will not work now either? I know some people purposely bypass the neutral light case there bike dies in higher gear they dont have to find neutral to start back up . This is a cb750 f2 btw if I didnt mention prior.


Ummm...if those indicator lights are LED lights, you may have a difficult time getting them to light up on the Neutral switch, or the Oil light. These are not low-resistance contacts, and the LEDs need that because they barely use any current. With the incandescent bulbs, the startup filament current tends to 'burn through' the oil films involved, which then establishes enough contact current to make them light up. The LEDs don't have this inrush of 'help'.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

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Offline 78whiteorbs

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Re: Think I fried my neutral switch
« Reply #10 on: November 20, 2013, 08:39:20 PM »
I resently saw a member here who was selling the mini led indicator lights as a set for all sohc bikes.  I read he mentioned that on later model sohc bikes the oil and neutral lights had to be hooked to two different. hot sources or they would not work.
Is it really so hard to replace a bulb with an led on these later model fours?

Offline HondaMan

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Re: Think I fried my neutral switch
« Reply #11 on: November 20, 2013, 10:13:06 PM »
I resently saw a member here who was selling the mini led indicator lights as a set for all sohc bikes.  I read he mentioned that on later model sohc bikes the oil and neutral lights had to be hooked to two different. hot sources or they would not work.
Is it really so hard to replace a bulb with an led on these later model fours?

What I have seen happen on these 2 switches is: once the engine gets run more often, the oil that is now old grease on those switch contacts finally gets washed away, and then the LEDs start to work better. Then, if the bike gets parked a long time (like winter) they don't work again until the cycle repeats. Often, this even happens with the incandescent bulbs as well.

The one thing I have found that helped is: the new O-ring on the neutral switch (it increases the pressure on the switch contacts), and a new oil pressure switch. The new pressure switch is used in the Honda outboard motors (still available from Honda) and the new contacts make the oil light MUCH brighter. This hints of better quality modern contacts inside. ;)

Some folks who REALLY wanted the LEDs for other cosmetic reasons have gone so far as to run a relay with the stock switches (because those simulate the incandescent lamp loads to the old switch contacts) and then connect the LEDs to the higher-quality relay contacts. These are some folks I call the "cafe ' extremeists" locally, who want appearance over function at any cost. Nice looking bikes, though! :)

It is often a good idea to remove the "safety relay" anyway, if you consider yourself smart enough to know that the electric start must only be used in Neutral or when the clutch is pulled in, or whenever you otherwise might need it, like when the bike stalled on clutch dump in hot traffic and a quick stab at the START button, in gear, will wake it right back up in time to save your life....the DOT never thinks of these things.

To remove it, just connect the 'grounding' wire of the START solenoid to the spare Green wire under the left side cover, near the seat. Then unplug the safety module and hide the red connector. Then when you press the START button, it will send the 12 volts to the solenoid, and all will be well again. ;)
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline Frostyboy

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Re: Think I fried my neutral switch
« Reply #12 on: November 20, 2013, 11:59:23 PM »
Sorry but what does OL stand for?

OL = Open Loop. These pics will illustrate.
When the circuit is complete with no resistance there is zero resistance.
If the circuit is "open" in this case the leads apart, the meter reads OL
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Offline 78whiteorbs

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Re: Think I fried my neutral switch
« Reply #13 on: November 21, 2013, 09:25:21 PM »
update: somehow I think I burned out every LED in the indicator. I don't know how though. I used another Led straight of the battery and fine as wine.