Old bike neutral switch, new harness.. (paging Brad Black)

[stopintime]

If I choose the wrong wire, what's the result?

[ducpainter]

If I choose the wrong wire, what's the result?

You can use your multi meter set on ohms to figure it out.

The ground wire will have continuity to ground...0 ohms...in neutral.

The other conductor will only have continuity in gear.

[stopintime]

You're fast for your age - lost me again...

My meter ohm switch has six levels:  20M, 2M, 200K, 20K, 2K/~ and 200/)))

One probe to random pin, other probe to ground. Whichever pin makes the meter go ZERO is going to be my ground, correct?

[ducpainter]

You're fast for your age - lost me again...

My meter ohm switch has six levels:  20M, 2M, 200K, 20K, 2K/~ and 200/)))

One probe to random pin, other probe to ground. Whichever pin makes the meter go ZERO is going to be my ground, correct?

I've had practice. 

The scale doesn't matter...continuity, or 0 resistance is. I'd probably use the 2K scale.

Yes...In neutral.

[stopintime]

It doesn't matter, but I don't understand how anything will happen if there is no + into the switch...

[ducpainter]

It doesn't matter, but I don't understand how anything will happen if there is no + into the switch...

An ohm meter has a battery to provide a small voltage source to obtain readings.

You and I have the advantage of being on the dumb end of the meter.

[brad black]

afaik.

the single wire switch earths thru the shift drum, and the drum has a strip of (going to have a look.  back now) plastic or the like laid into it.

the two wire switches use a bump on the shift drum to push the end of the switch in to make contact.  so you have the run the switch for the shift drum, not the cases.

i have a 6 speed 696 box i was going to try to fit to an early 750 (pre 98) and apart from a lot of cutting bits off i had considered how to make the late drum work with the old switch, basically coming up with a round headed something (rivet, etc) fixed to the drum.

if it is in one piece it may need to become many again.  or start thinking outside the cases (punny, huh?).

[stopintime]

How can it earth to the drum if there is plastic where it touches? (if I read you correctly)

Besides that, are you basically saying that I have to use my single wire switch and make a new location for it in the engine case? That's not a simple solution....

I could learn to live without a green light, but the side stand blocking any running and the clutch lever to be pulled before every start is problematic...

[brad black]

the plastic is not full circumference, so there is a short steel section, which corresponds to the switch at neutral.  as i understand it anyway.

is the single wire switch too long or too short?

[stopintime]

Judging only on how deep the single wire switch sits, I'd say it's too short.

half of it can be seen behind the spring:

[Speeddog]

Near as I can figure, you've got a contact-style shift drum in a plunger-style switch crankcase.

No way to fix it properly without splitting the cases, and even that might not be possible.

If you connect the neutral-switch wire from your harness to ground, it should allow the bike to start.
You will have a perpetual green light on the dash, and the ability to try to start it in gear.

Neutral Switches:

Upper is plunger-style, it's actually a switch.
Available in two-wire (as shown) and single wire for sure, perhaps more.

Lower is contact-style, which grounds the terminal to the shift drum.
Available in at least two nearly identical versions.



Shift drums:

Upper is plunger style, lower is contact-style, you can see the plastic inlay.



Closeup:

[Howie]

Is it possible the new style switch might work since Lars still has the 6 speed?

[Speeddog]

Is it possible the new style switch might work since Lars still has the 6 speed?

The new sensor is a larger diameter, so it won't fit the old cases.

It *may* be possible to drill and tap old cases to fit the new sensor.
But not a good thing to do on an assembled motor.

There was a DP 6-speed kit available in the past, perhaps it had the plunger-style shift drum.
But that requires finding that "maybe" part and splitting the cases to install.

[brad black]

if the end of the plunger type sensor hits the drum fit it and cut one of the wires and solder it to the body of the switch.  that way it will earth against the drum if the switch conducts.

which it won't thinking about it.  cut it up and make it work using the body of the correct switch for the cases.

[stopintime]

I will ground my harness' single wire - it works as described. Green light always on, must do blind searches for neutral and make sure I have found neutral before leaving it running on the side stand. Not ideal, but better than my current clutch switch dependency.

Later, I can see if the bike builder is able to relocate the stuff inside the single wire switch over to the dual wire switch. The depth is different (switches, drums and cases), so it might require some machining/drilling from the outside and/or new positioning of the stuff inside...

We'll see.

Thanks for your help so far - please comment again if you have more