Author Topic: Neutral light on but not really in neutral?  (Read 143 times)

briankay

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Neutral light on but not really in neutral?
« on: June 03, 2017, 09:07:24 PM »
I'm new to motorcycling, and also very new to my Sym, but here's the (maybe silly) question.  Yesterday, I slowly released the clutch while the green neutral light was on, and the bike lurched forward and stalled.  A few minutes later, without touching the gear shift, the light went from on to off (or maybe the reverse, I can't quite remember).  So, is some amount of play between the light and the actual gear position common? Thanks for any thoughts. 

redridinghood

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Re: Neutral light on but not really in neutral?
« Reply #1 on: June 04, 2017, 08:51:14 AM »
You bought your bike new and it's under warranty, correct?

We know who's going to fix it. 😉

The neutral light wire or neutral light switch is finding ground when it shouldn't

See part 10 http://www.symcanada.com/_techSpecs/techWolf/PA15C1-C(E12)GearShiftSpindleAssy.pdf

See parts 8 9 and 14 http://www.symcanada.com/_techSpecs/techWolf/PA15C1-C(E16)LCrankCaseComp.pdf

Nice pic of similar if not exact same of the neutral rotor and neutral switch from a Honda CB125 parts 10 and 8 on Sym diagrams http://www.ebay.com/itm/1970-1979-HONDA-CB125-CT70-CB100-CL100-SL125-NEUTRAL-LIGHT-SWITCH-SL100-XL125-73-/151635398333

Looking at the neutral rotor in the photo, we can see 2 tabs on it. The tab at the 3 o'clock position fits into a groove machined into the shifting drum, so the rotor will rotate with it when you shift gears. 

The tab at the 12 o'clock postion is the contact for the neutral switch. When the transmission is in neutral, this tab is aligned and in contact with the neutral switch, completing the circuit and lighting the neutral light bulb.   

I don't believe this neutral switch to be of a plunger type (a spring-loaded piece, when in contact with another protrusion, depresses and completes the circuit), so no stuck plunger to be concerned about.

And since the neutral light DOES come on, my first thought is to give the neutral switch an OK.

I'd check the wire running to the neutral light bulb (the same wire that goes inside the left engine case and connects to the neutral switch) and see if it's finding ground because of damaged insulation.

You might be able to replicate this problem by jiggling this wire with your hand...

Take it to the dealer..😜

Everything metal on your bike, that is in contact with the frame, is ground
« Last Edit: June 04, 2017, 10:22:13 AM by redridinghood »

briankay

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Re: Neutral light on but not really in neutral?
« Reply #2 on: June 12, 2017, 12:22:19 PM »
Thanks a lot, redridinghood, for a very thorough answer.  I'll start checking all of this out.  (My dealer is an hour away by busy highways so I'm not quite sure how I'll handle dealer repairs yet. Hmm.)
-Brian