Yet another neutral light issues...

[drgnfli]

Hello all,

It's been a while since I've been to this forum (maybe because my bike was running so well the past couple of years).  Anyway,  got a 1979 R65 with about 12 k miles on it.  Two days ago, sitting on a red light on a busy street,  the bike just died suddenly.  Well,  I said to myself shift to neutral and start the bike...no start, no neutral light.
Neutral switch is new (changed it last year from Capital Cycle).  So I started to look for loose connection but found none...battery is strong and have palenty of gas.  Towed the bike home and checked it again. This time have a very DIM neutral light but only if you shift to first gear or second gear and no neutral light on neutral.  Any help to get this baby back on the road will be appreciated...

[Bob_Roller]

Pull the clutch lever in and try starting the engine .

There are two safety interlock circuits to prevent the engine from starting when the bike isn't in neutral .

Obviously the neutral light on the instrument cluster, if that fails, the switch at the clutch lever on the handlebars, will allow you to start the bike with the transmission in other than neutral .

The OEM BMW neutral switches are not known for their longevity, but a year is a bit quick to fail .

Check the wiring for the neutral switch, not too uncommon to find the insulation cracked and breaking away from the metal conductor of the wire  in that area, along with the wiring for the engine low oil pressure switch .

Don't know how mechanically, or electrically inclined you are, but there is a two wire connector on the left side of the bike around the left side cover, separate the connector halves and place a bare wire into the side of the connector that has the wire that is brown with a black spiral band, with the key in the on position touch the other end of the wire to the engine or transmission case, the light should come on bright like it always does .

That will confirm the switch and wiring at the transmission is causing your problem .

[drgnfli]

Thanks Bob for your reply.  Bought the bike without the clutch safety feature...guess the PO removed this safety feature,  so I always find neutral to statrt the bike.  I connected the two wire going to neutral switch to see if my neutral switch is bad...no light.  I was thinking that there's a short in the electical system somewhere that's why it died suddenly on that day and affected the starting system...just don't where to start.

[nhmaf]

As part of the process, I would definitely get a new clutch lever switch and wire it up -- it could save your bacon in the middle of traffic!

As you can see here in this simplified schematic, the system is designed so that EITHER the clutch lever switch OR the neutral switch at the bottom of the transmission will allow the starter relay to activate.    The specific wire colors, etc. we can help you with.   Sometimes the diode in the schematic fails in a shorted condition -- when that happens the neutral light turns on every time you pull in the clutch lever, which is sometimes why ill-informed people remove the clutch switch.

[Barry]

Nice diagram.

So much easier to see what's happening when a section of the main wiring diagram is seen on it's own.

[drgnfli]

Hi Bob,

Did separete the connector on the left side of the bike. Used a bare wire on the brown with back spiral band and touched the engine case.
Two things happened...first, as soon as a I separated the connector,  the neutral light came out, not very bright though (transmission in neutral).  2nd,  as soon as I touch the engine case with bare wire that's connected to the brown wire with black stripe,  the light went out.  Bike still dead on two occasion.  Still don't know  what this means...

nhmaf,  thanks for the diaghram...I am on the look out for a clutch lever switch,  scanning ebay right now.

[Bob_Roller]

As the bike sits now, are any other problems with the bikes electrical systems .

Lights, horn, turn directionals ??

Or does everything else work ??

[drgnfli]

Everything works on electrical system,  except for the starting system.  I am wondering. maybe in the diode,  starter relay, starter switch,  starter itself and just plain electrical short somewhere in the starting system.  I hate to guess and start replacing parts that does not need replacing (I've done this before and it's not an enjoyable experience not to mention it hurts the pocket).  The thing that baffled me is why the engine died suddenly and followed by the starting problem...any correlation between this two?

[Bob_Roller]

With the key in the "ON" position, do you get the lights for low oil pressure, GEN, etc ?

[drgnfli]

No Gen light or low pressure light...high beam indicator works...

[Bob_Roller]

I think we're getting somewhere now !!!

I just went out to my '81 R65, and I can duplicate the same situation you have, by turning the "KILL" switch to the kill, or off position .

Check the switch for proper position , hopefully that's all it is, if not, it's pointing towards a faulty switch then .

[nhmaf]

+1 with Bob - it sounds like your kill/stop switch is on, or possibly malfunctioning, given the info that you've provided thus far, and the nonexistent clutch switch.

[drgnfli]

Wow Bob,  you hit the nail on the head!  Disassembled the kill/start switch and found that there's a short in the wiring.  I was checking the wirings when suddenly there's a short spark and all the lights on the gauges lights up like a Christmas tree..Gen light. oil pressure light and a very bright neutral light.  This happened for just a few seconds and went away.  Tomorrow I will check the wirings one by one.  Thank you and the rest of the guys in the forum for helping me out...Save me some bucks and a lot of headache,  now if these rain East will stop then I can ride.  Thank you guys!!!

[Bob_Roller]

Glad to hear you found the cause of your problem !!!!!!!!!

OK, now just send some of that excess rian to central Aridzona !!!!!!!

[Semper Gumby]

Hi Bob,

Yeah I guess instead of an oil cooler on your bike it would now be an oil pre-heater?

(If you had one)

Bill