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Neutral safety switch?

80K views 43 replies 15 participants last post by  Here 2 help 
#1 ·
2007 trx90. The green neutral indicator light recently stopped coming on even when in the neutral position... After clicking the shifter up and down a few dozen times I can get it to come on and only then will the quad start. Is this a neutral safety switch issue or could it be something else
 
#2 ·
First guess is a bad neutral switch switch or a bad wire connection, but it could be a bad key switch also.

The neutral light is the only thing that lets you know the power from the battery has mad it to the black wire when the switch is turned on.

Check the battery terminals first (clean & tight) - then take the light green wire with the red stripe off the neutral switch and connect to ground (this should turn on the light) or jumper from the switch to ground (same thing - it turns the light on) if the light turns on every time you touch the lg/r wire to ground, replace the switch. If you leave the wire grounded, the light will stay on all the time and it will start in gear.

If the light is intermittent when grounding the lg/r wire, you might have a bad wiring harness connection, bad engine ground, bad neutral light bulb or socket or something off the wall that I haven't covered in this brief troubleshooting guide.

Good luck
 
#8 ·
What part number did you get? I took a wild ass'ed guess and looked at a TRX350FE (Honda had FE, FM TE,and TM models in 2002) and there is no neutral switch on any of them - there is a "gear change switch" which sends signals to the display to indicate neural and each gear.

If you are not sure of the year and model, please provide VIN and I will tell you exactly what you have.
 
#10 ·
The part you got is located on the LH side of the rear engine cover kind of to the RH side and slightly lower than the gear change switch. Should be a single light green wire with a red stripe running to it. If you take the wire off and touch it to ground with the main switch on, the neutral light should turn on.
 
#13 ·
Here 2,
So that just isn't there (no idea why). However, up on the left hand side of the rear cover I found a pair of wires. I traced them back to a junction on the right side of the frame and disconnected them. If I short out the green one - N indicates on the dash. If I short out the gray one - R indicates on the dash. So those two wires must be attached to the switch (or whatever) inside the rear case?? Do I just simply have the wrong part or do I need to remove the rear cover to get to it?

Thanks again for all your help!!

Biff
 
#18 ·
Hello, I'm working on an old 91 TRX200D. I had a crack in the left crankcase cover due to a chain mishap and had to remove it to get it welded. I removed the sator and change switch. The change switch had also suffered some damage as some of the top plastic molding had been crushed inwards and the top was easily separated from the case. The switch pole turned fine and I could feel it making contact when I spun it, so I figured it was just a very simple contact switch. I used some JB Plasticweld epoxy to fill the top gap and fitted it all together and reassembled it into the case cover after I got it back from the welder. After getting it all back onto the motor and filling oil back up, I went to start it up and the red reverse light was on with the trans in neutral. I thought maybe I mess up and got the switch reversed 180 so I drained the oil again and separated the cover enough to rotate the pin and tried that, but that created a situation where the rev light only came on when I jacked up to 4th, so I reverted back to the way I first had it, which engaged smothers into the sloot and had the flat of the post at the top so the keyed indicator points to the N on the case. That seemed to be right. So back to the first problem. The red rev lights when I'm in R and N and turns off as I go up to first and above. The start button will not work in N or any other gear for that matter. If I check the continuity on the Lg/r wire coming from the switch, I get nothing in any gear including N. I do get continuity on the white wire when in either R or N. I believe should be getting it in just R and I should have it for the Lg/r wire only when in N.

It would be great if I could buy a new one, but they seem to be completely unavailable. Does anyone have any idea how to rehab one of these switches and what sort of things to check if I pull this all back out. I've read about doing a bypass toggle switch on the Lg/r wire, but I have a feeling the live circuit for the reverse will block me at the CDI if I can't kill that too. Frankly I don't want to have to mess with rigged up switches to replace the function of the gear switch.

Any suggestion on how to fix switch itself or a source for one would be greatly appreciated. (Honda 35759-HF1-000 SWITCH ASSY., CHANGE )

Thanks
 
#19 ·
It's a shame that manufacturers design a complicated device for a simple job and then only use it for 7 years, but things are not supposed to last in perpetuity. You will only find the part in a used unit or on the shelf of a Honda shop who has forgotten they have it. I do not know of a way to fix it, but a quality machine shop may be able to duplicate it for less than a thousand dollars. I suggest you try to find a 90 to 97 200D engine to steal the part out of as the chance of fixing the old one is pretty much zero and finding a new one is zero. Finding a used one is iffy - I found 5, but they had all been robbed of the LH cover and gear indicator switch.

Good luck restoring the dinosaur.
 
#20 ·
Thanks for the 'positive' encouragement. I actually had ordered one a couple weeks ago only the have the order refunded with an apology that it really wasn't in stock. So I guess its hilly billy repaire time. I pulled it backout this morning and found that my misadventure in trying to do a 180 cause me to bust off half of the spring pin. Luckily I found one that will work at Tractor Sup in town and won't have to wait or pay shipping for just that. At least you can get those. Other issues I discovered on close inspection, the Lg/r connect was just holding on by a few wirers and needed to be resodered. Whomever tried to fix this swich was only a bit worse at that then I am. But the real issue was inside. There is a helical sping contact that need to touch a plate that has the gray and the white contacts connected and then the nub on the spring contact touches a contact spot compleating the circuit to the Lg/r. The gray white contact plate was bent down too far and broken at the contact spot end. It took some reposition to reshape to a smooth ramp where the nub can run back and forth over it and then bridge the contact points. Since the plate was exposed from the crumpled plastic I leaded in some solder behind it to build it up. Got the switch rotation contacts working and giving good connectivity results with it hand held in the case shell. I then set about building up the broken plastic head with JB Weld. Will test fit into the mount once dry. May have shape, sand and add more to get the right contour. So for so good I guess.
4305
4307
4306
 
#21 ·
So the switch repair seemed to go ok. Got the crankcase put back together and on the bike and the starter motor turns the engine when I'm in neutral and it almost tries to start, especially if I hold in the throttle, but it just won't fire. So I checked the ignition coil and the wire connection between the coil wire and the cap seemed iffy. The cap pulled right off the coil wire without effort. I put it back on, pulled the plug and tested for spark. Can smell gas. I should mention bike ran just fine before taking off the crank case cover. Spark is almost not there at all, every so often some weak spark will jump. I pulled the coil out, tested resistance and the coil itself seems ok and in range but the cap has complete resistance until I set my multimeter to the 200M setting. So I'm thinking the cap is bad. New OEM coil came today but still waiting for new OEM cap. I did find on Amazon a cheap coil and it arrived yesterday. https://www.amazon.com/gp/product/B00YWM52S2/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 I tested it and the resistnace was a bit lower than the rang at 2.5 Ohms from green to cap. The cap seems to not fit well on the top of the NKG DR8ES-L spark plug threaded top. So I picked up a Champion 809 RASHC thinking that would fit the cap better, but the top stud was too thick for the cap to fit it. So no joy yet. I have checked the pulse generator resistance and that seems to be within speck. The bike is old and bolts are rusty, not easy to get the front fenders off without busting that all up so I haven't checked the CDI yet. I keep going back to what I have touched. The bike sounds to me like the timing is just a bit off, but according to the workshop manual there is no way to adjust the timing and it is all controlled by the CDI. When I took the crank case cover off I got a bit ahead of myself and made an attempt to undue the crankshaft bolt. All I succeeded in doing was rotate the crank a few times before I came to my senses that was completely unnecessary. Is it at all possible that in hand cranking the motor like that I got it off of it's timing and if so, is there a way to get it back? Seem like there is no way to even check the timing via the inspection port unless the motor is running at idle Do it need to get it set to TDC before doing some part of the cover replacement? It didn't seem to me like it should have mattered at all, but now I'm second guessing myself on it. I'm still hoping I just need the OEM plug cap with the new OEM coil and it will fire right up, but while I wait, I might as well reach out.

Many Thanks!
 
#22 ·
Well, if you didn't have the cam out when the engine was turned, it would not change the timing and the spark timing is set by the crankshaft/flywheel, so the timing cant be changed without moving the flywheel on the crankshaft.

The spark plug cap has a 5000 ohm resistor built into it - measure just he cap and it should be close to that - a tight fit on the plug is not required - you will actually get a stronger spark with a loose cap, but the cap may come off the plug when thrashing the machine which would be irritating. The cap is a tight fit simply to assure it does not come off while riding.
 
#23 ·
Thanks for the confirm that the timing shouldn't have shifted. It's possible that I'm not using my meter right, but I don't get a reading at all on just the cap unless I set the dial up to 200M and then it is all over the place from 8.5M to 15M. I just get a 1 at 200, 2k and 200k settings. The wire itself reads 3.0K fine at 200K setting. I really don't know how the cap itself could have gone bad. I can see the connection to the wire getting messed up, but I guess I don't know what would make the cap itself fail from just doing nothing. Still waiting for the new cap. It was supposed to have shipped friday, but now partzila is saying it won't ship till the 23'rd. Very annoyed. Yet from what your saying, the coil I got off amazon where the fit is a bit loose should be fine and I did see some spark, just not good consistent spark.

I also suspect I may not have properly tested the pulse generator as that was out and being kicked around with the sator for a bit. Could being in physical contact with the magnets on the sator some how mess up the pulse?

Other shot in the dark... The black wire on the rectifier was broken and I used a crimp connect to reconnect it before I started tested after repairing the neutral switch. Is there any way that disconnecting that black wire might be some sort of hack around a failing CDI unit. I'd hate to undue that fix just to test this theory out.

Thanks again!
 
#24 ·
Here's the ignition system:
4317

One thing at a time:
The CDI does not needs voltage to create a spark.
The alternator supplies AC voltage to the CDI unit to charge the capacitor and the pulse coil tells it when to fire.
The spark is killed when the black/white wire is connected to ground.
Battery voltage is supplied to the unit via the white wire - this is just to let the unit know if it's in neutral or reverse.
In neutral, the starter motor will run when the button is pressed.
In reverse the voltage is decreased and the unit limits RPM to a preset value.

You can't determine much from a multi-meter or ohm meter - you need a peak voltage tester to troubleshoot.
If you have spark on every stroke regardless of the strength of the spark, the pulse coil is doing it's job.
To diagnose a weak spark, you first need a new spark plug.
Assure the plug cap has around 5K resistance - if that's good you need to check the peak voltage output of things.
The pulse coil is typically 3 to 5 volts peak (a peak meter converts AC to DC and displays on the DC scale)
The charging coil of the alternator is about 35 to 45 volts at cranking speed (higher at higher RPM)
The output from the CDI to the coil is about 100v
The output from the coil to the spark plug is about 30 to 40,000 volts

Let me know if this helps. I can send you a PDF of the service manual if you need it.
 
#25 ·
This is all very helpful. I actually have the shop manual with this diagram, Just not the knowledge and experience to fully understand how the circuits operate. Your explanation is great! I'll see about getting my hand on a peak voltage tester. I don't think I'm getting spark on every stroke, but I also don't think holding the plug out of the engine and trying to touch the barrel to the engine is the best test method either. I can can some spark, but it's not at all consistent. I'm wondering if I might have a short in the harness that goes down into the crankcase from you comment on the black/white wire touching ground. I'm traveling now, so will be a number of days before I'm back at this. But again, very grateful for the assistance.

Chears!
 
#27 ·
Here2Help, one other thought occurred to me while driving around. Maybe I messed up the switch. Can you tell me if the red rev light should go out when switched in to neutral? Mine stays on, so I now have both the red rev and the green nut light active at the same time. You said CDI will reduce voltage when in Rev.. this might make it hard to start me thinks and explain the symptoms. When I was looking at the physical aspects of the switch, I was testing the connectivity out of the case. The lower spring would normal make contact with ground by scraping the bottom of the case. I got it into my head that the top of the spring contact needed to touch the ramp and the nub touched the neutral contact spot at the same time to close the circuit and give connectivity to the green wire.. but now I'm thinking those should not be touching at the same time and when in the case the green wire will connect to ground when the bottom of the spring is touching the case. Does this sound like I'm onto something?
 
#28 ·
By Jove, I think you've got it.

The design is the nub on the shift drum contacts the neutral contact when in neutral and the nub contacts the other when in reverse - no connection between them - when in reverse the battery positive is connected to ground via the switch, but the current has to flow through the resistor which lowers the voltage. The resistor is in actuality the reverse light bulb filament.

Try to get it fixed so the reverse light is on only when in reverse and neutral is on only when in neutral and I think you will have solved the problem. A work around would be to disconnect the reverse light and if the neutral light does not work properly simply ground the wire. With the reverse light disconnected one of two things will happen; it will die when put in reverse or it will not limit engine speed in reverse. If the neutral light works properly the no worry - if the neutral light does not come on, you can't engage the starter motor - if you wire the neutral wire to ground so the light is on all the time, I believe it will start (or try to) when in gear.
 
#29 ·
Bingo, I think that will be it. It just doesn't make sense that other things went south while I had the case off and oil out and I know I intentionally allowed for the rev and neutral to be touching the way I shaped that ramp under a mis understanding on how it worked. I can pull that off and should be able to get that case off again to alter the ramp profile. I'll let you know in a week or so how I made out. Cheers!!!!
 
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