CBF125 Neutral light issue

[JamS]

Hi, having an issue with my bike and wondered if anyone could shed some light on it.

Occasionally when I go to start the bike the Neutral light doesn't come on. So long as I put the kick stand up and pull the clutch in (not sure if both of these are necessary but it's what i've been doing) the bike will start and as soon as the engine starts the neutral light mysteriously comes on.

This has happened 4 or 5 times in the past 2 months and i'll have a week or so where everything is working perfectly, then i'll go to start the bike and the neutral light won't come on.

I've just passed my test (woohoo!) so looking to sell this and get a bigger bike - it's in really good condition but I'm not happy selling it with this issue.

I'm no mechanic but like a bit of DIY and willing to have a go so please make any instructions easy to understand Thanks!

Jamie

[ThunderGuts]

Is the bike definitely in neutral when you turn it off at the end of a ride? I.e. light on and you can release the clutch with the engine running? Just wondering if you're sort of "nearly" hitting neutral somehow when you turn the bike off and it takes the engine spinning to fully engage neutral?
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TG.

[JamS]

Yes - definitely in Neutral at the end of a ride as I let the clutch out (engine still running) and walk backwards with the bike (whilst i'm on it) into the bike parking bays or the driveway.

When I start the bike back up the Neutral light comes on straight away when the engine starts, it just doesn't show when the bikes not running.

First time it happened I was there for ages clicking between 1st and 2nd gear trying to get the light to come on, but nothing until the bike is running. Doesn't happen every day, hadn't happened for a couple of weeks (I changed the bulb) so I thought that was it fixed but happened again yesterday

[Meatybeaty]

Check continuity on the Neutral switch wire (Lg/R) to earth, if its the switch itself you will have to take off the sprocket cover to get to it

[rpsmith79]

Could easily be a broken/dodgy switch

My old CG125 had a dodgy neutral switch, it was actually broken in half, and under certain circumstances would light up, and some others would not, depending on whether the 2 broken parts were touching together or not

They are cheap and simple enough to replace anyway
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Current Bike: Honda CG125 ES4 // Honda CB600FS Hornet // Triumph Street Triple R

[JamS]

Ok - so I have no idea what 'check continuity' means... Like I said i'm pretty new to this stuff! I've got the Haynes Manual out now, checking the connections, fuses etc but it all seems ok - might just get a new switch to be on the safe side.

Would a garage charge a fortune to fix it? I don't mind having a go but it's going in for an MOT in a couple of days anyway so could just ask them to do it.

[Meatybeaty]

[JamS]

I've just had a look at where the neutral switch is and ordered a new one Hopefully that will fix it! Thanks for your help!

[Hetzer]

Same issue, we picked up my son's first bike last night (CBF125) and the neutral light is intermittent. I took the sprocket cover off, there's a gizmo held on with two bolts (8mm) with a single green wire coming out of it. Removed it, oil comes out the case so figured it might be the oil-pressure gizmo instead. It's physically intact but looks solid-state, no way to fiddle with it.

Googled it, it's the neutral switch. The bike has less than 6000 miles on it (2013 reg), o-ring is good, peg inside springs in nicely, wire is undamaged. WTF.
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[Easy-X]

FYI a simple neutral "switch" is made up of two components.

1) The gear selector shaft has a little sticky-out gold "finger"
2) A simple plastic disk with a contact pad

As you shift gears the finger rotates to different positions. When you're in neutral this position lines up with the contact pad on the plastic disk.

There's a wire on the other side of the plastic disk that is soldered/welded/screwed to the back end of the neutral contact pad. As the engine itself is an earthing point. When the finger and pad line up the wire also becomes an earth point.

Therefore a simple neutral indicator could be a light bulb with a positive feed on one side and the wire leading to the aforementioned neutral switch on the other. So the circuit should be:

Battery Positive > Ignition Switch > Neutral Bulb > Neutral Switch > Engine Frame > Battery Negative.

"Checking continuity" is easiest with a multi-meter. You would check there is a "continuous path" from say one end of a wire to another. In this case, if one suspected the neutral switch was faulty, you would switch the multi-meter to "resistance" (some have a "continuity test" which makes a helpful beep!)

Step 1: disconnect the battery! (never a bad idea when messing with electrics)
Step 2: put one probe of the multi-meter on the side going to the bulb. Trace the wire from the neutral switch till you (hopefully) find a connector you can unplug and then touch the probe to the contact in the plug.
Step 3: put the other probe on the battery negative terminal.

If in neutral the multi-meter should read low resistance (and probably beep.) If out of neutral the multi-meter should read high resistance (possibly it says "overload" or "out of range".)
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter