Author Topic: "False Negative" Neutral?  (Read 1027 times)

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Offline MosquitoJones

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"False Negative" Neutral?
« on: March 02, 2009, 07:39:57 AM »
A couple of times recently I've gone to start my bike, and when I press the starter button nothing would happen.  Little fudging would get it to fire right up.  I thought there might be some dirty connectors or a small short in there and was planning to give it a look-see.  But this morning I think I discovered what the problem really is.

I always start my bike in neutral.  Just coming out of winter into (semi)decent riding weather requires I use the choke, so I've got one hand operating the choke and the other starting the bike.  Well this morning no matter how much I jiggled and cajoled the starter she still wouldn't turn over.  On a whim I engaged the clutch (still in neutral) and the bike kicked over.  I know the bike actually is in neutral, as I could roll her about easily with no clutch and there was none of the scraping sound you might get if the bike wasn't fully in neutral.  Is this something that is easy to fix?  I've had no other problems with shifting or anything that might indicate problems in the transmission itself.  Bike is an '82 CB650, no custom, not SC.
'82 CB650, 65 CP77 Superhawk in chunks

Offline mystic_1

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Re: "False Negative" Neutral?
« Reply #1 on: March 02, 2009, 09:04:59 AM »
What is the neutral light doing?  Does it come on reliably when it's in neutral?

It's possible that the neutral indicator switch (usually on the transmission somewhere) is going bad or has a bad connection.  Bike thinks it's still in gear, won't run starter.  Pulling in the clutch lever overrides this.

So, check your neutral switch and associated wiring would be my first guess.

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Offline j-conn

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Re: "False Negative" Neutral?
« Reply #2 on: March 02, 2009, 09:08:27 AM »
im sorting that prob out too...
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Offline MosquitoJones

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Re: "False Negative" Neutral?
« Reply #3 on: March 02, 2009, 09:51:02 AM »
What is the neutral light doing?  Does it come on reliably when it's in neutral?
Yep, the light works normally and the transmission seems to be fine; I don't get false positive neutrals.  I figured there was a sender in there but I don't know how accessible it is or how easy it is to find a replacement.
'82 CB650, 65 CP77 Superhawk in chunks

Offline Hush

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Re: "False Negative" Neutral?
« Reply #4 on: March 02, 2009, 10:32:32 AM »
I'd be cleaning the clutch cut-out switch, probably got a bit gummed up and sticking in the "closed"position.
A bit of warm water and some dishwash liberally applied with an old tooth brush works well but whatever you have for cleaning should work Mosquito.
Your neutral sender is inside the left side chain/front sprocket cover (requires removing gear lever and 4 bolts).
Tucked up just under the starter motor you'll find it, a bit of degreaser squirted in and around then a flush with water should clean the area out, if you want to you could touch up the contacts for the neutral sender with some very fine sand paper or a nail file.
 
« Last Edit: March 02, 2009, 10:36:31 AM by Hush »
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline MosquitoJones

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Re: "False Negative" Neutral?
« Reply #5 on: March 02, 2009, 11:23:11 AM »
Thanks Hush, I'll give it a peek ASAP!  :)
'82 CB650, 65 CP77 Superhawk in chunks

Offline jaknight

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Re: "False Negative" Neutral?
« Reply #6 on: March 02, 2009, 06:49:52 PM »
Hi Mosquito,

Yes, Hush has the right idea.  Get yourself in there and do some cleaning.

It is usually a dirt, grease, electrical ground problem.......... those sender units can be very touchy about that....... had it happen on my bike.   ;)

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Offline mystic_1

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Re: "False Negative" Neutral?
« Reply #7 on: March 02, 2009, 07:05:36 PM »
I dunno, if the neutral light is behaving properly than I suspect that the sender switch is OK.  This model has a diode in the safety system?  If so maybe it's failing...

<runs off to find a CB650 wiring diagram>

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Offline MosquitoJones

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Re: "False Negative" Neutral?
« Reply #8 on: March 03, 2009, 08:27:26 AM »
Hmm, well I guess I'll start with the cleaning.  Sad because while the week is supposed to be nice the weekend is set to be cold and crappy  :'(  The problem doesn't make the bike inoperable, it's more of an inconvenience. 
'82 CB650, 65 CP77 Superhawk in chunks