Does not starts in gear

Discuss all things 1970 & later Airheads right here.
User avatar
gspd
Posts: 1041
Joined: Tue Aug 03, 2010 8:04 pm

Re: Does not starts in gear

Post by gspd »

OK, don't know if we should do this by email or here.
Might be a bit boring for everybody else.

I'm going to make this as concise as possible, please don't interpret this as me being condescending, I just want to keep it very easy to follow.
Anyways....here goes...

CIRCUIT TRACING 101
(I'm assuming that your test light has a thin sharp pin probe at one end and alligator clip at the other end.)

Step 1.
Connect the clip of the test light solidly to BATTERY POSITIVE terminal.
(touch the pin probe to battery negative terminal just to confirm that your test light is working properly.)

Next, touch the pin probe to the transmission case, engine case, exhaust system, frame, handlebars, and so on.
It should light up on all these surfaces which shows that they are all solid GROUND.

The light should be about the same brightness on every ground. If it is very noticeably dim, you have a poor ground.
If it stays off, you have no ground.

The clutch switch has 2 wires, a brown and a brown/yellow.
Now, with the clutch switch connected as it should be, poke the pin probe through the insulation into the BROWN wire. Do this in an inconspicuous spot if at all possible. If your test light probe tip is not needle thin, it might noticeably damage the insulation; in this case you can use a very thin sewing needle to pierce into the wire instead and touch your probe to it.

QUESTION #1: Does the brown clutch switch wire have GROUND?
QUESTION #2: Does the brown/yellow clutch switch wire have GROUND when you pull in the clutch?
Mechanic from Hell
"I remember every raging second of it...
My bike was on fire, the road was on fire, and I was on fire.
It was the best ride ever!"
cpazambrana
Posts: 48
Joined: Wed Apr 14, 2021 12:59 pm

Re: Does not starts in gear

Post by cpazambrana »

gspd wrote: Sat May 01, 2021 11:09 am OK, don't know if we should do this by email or here.
Might be a bit boring for everybody else.

I'm going to make this as concise as possible, please don't interpret this as me being condescending, I just want to keep it very easy to follow.
Anyways....here goes...

CIRCUIT TRACING 101
(I'm assuming that your test light has a thin sharp pin probe at one end and alligator clip at the other end.)

Step 1.
Connect the clip of the test light solidly to BATTERY POSITIVE terminal.
(touch the pin probe to battery negative terminal just to confirm that your test light is working properly.)

Next, touch the pin probe to the transmission case, engine case, exhaust system, frame, handlebars, and so on.
It should light up on all these surfaces which shows that they are all solid GROUND.

The light should be about the same brightness on every ground. If it is very noticeably dim, you have a poor ground.
If it stays off, you have no ground.

The clutch switch has 2 wires, a brown and a brown/yellow.
Now, with the clutch switch connected as it should be, poke the pin probe through the insulation into the BROWN wire. Do this in an inconspicuous spot if at all possible. If your test light probe tip is not needle thin, it might noticeably damage the insulation; in this case you can use a very thin sewing needle to pierce into the wire instead and touch your probe to it.

QUESTION #1: Does the brown clutch switch wire have GROUND?
QUESTION #2: Does the brown/yellow clutch switch wire have GROUND when you pull in the clutch?
The brown cable has ground (light went on)
The brown/yellow also has ground. Both with the clutch pulled in or not.

I did the same with the connector behind the side cover which is the one that connects to the neutral switch and the oil pressure switch. Same results. Email is cpazambrana@yahoo.com although I don’t mind doing this here.
1983 BMW R80RT
1976 BMW R60/6
Still looking for a Honda CB77 Superhawk
cpazambrana
Posts: 48
Joined: Wed Apr 14, 2021 12:59 pm

Re: Does not starts in gear

Post by cpazambrana »

I also sent you a pm here.
1983 BMW R80RT
1976 BMW R60/6
Still looking for a Honda CB77 Superhawk
Seth
Posts: 275
Joined: Thu Aug 12, 2010 4:45 pm

Re: Does not starts in gear

Post by Seth »

you should be getting some voltage on the brown/yellow wire with the ignition on, IN GEAR (no neutral light, and the bike has the problem that it won't start), and the clutch pulled in (a needle pierced into the insulation connected to the red lead from your multi meter and the black wire connected to a ground). From the simplified drawing from Rob, power ONLY goes to the clutch switch when the ignition is on and the starter button is pressed. I may not be full 12v as it's going through the relay which adds resistance.

If you don't have power there, you have to trace that brown/yellow wire back to where it gets to the starter button. It may (probably?) go into that bundle of wires you saw in the headlight and connect into the fuse block.

I got this picture off Ebay.
Note the 2 pins on the second row, pins 3 and 4 marked "85b"
I believe this is where the "hot" side of the clutch switch attaches. The second pin in that pair should come from the starter button, as per Rob's drawing. It should get voltage when the starter button is pressed (ignition on).

FYI, but since the starter button functions, this is not a problem, the blue/yellow pair of pins (1 and 2, top row) marked "85". That come from the Starter Relay and go to the Starter button (as per Rob's drawing).

The point being, BMW does not seem to wire things "point-to-point", but instead makes a number of these connections in the "fuse block". They do a pretty good job color coding and numbering in the fuse block for you to follow.

Feel free to PM me if you have additional questions. Hope this helps.
Attachments
BMW Fuse Block.jpg
BMW Fuse Block.jpg (239.05 KiB) Viewed 757 times
User avatar
gspd
Posts: 1041
Joined: Tue Aug 03, 2010 8:04 pm

Re: Does not starts in gear

Post by gspd »

I'll let Seth take over, too many cooks spoil the broth.

'later

PS . Seth, I believe you are misreading the wiring diagram or have the wrong one.
Mechanic from Hell
"I remember every raging second of it...
My bike was on fire, the road was on fire, and I was on fire.
It was the best ride ever!"
Seth
Posts: 275
Joined: Thu Aug 12, 2010 4:45 pm

Re: Does not starts in gear

Post by Seth »

Please feel free to correct me.
You learn more when listening than speaking.
I'd like to hear what you have to say.
cpazambrana
Posts: 48
Joined: Wed Apr 14, 2021 12:59 pm

Re: Does not starts in gear

Post by cpazambrana »

gspd wrote: Sat May 01, 2021 4:41 pm I'll let Seth take over, too many cooks spoil the broth.

'later

PS . Seth, I believe you are misreading the wiring diagram or have the wrong one.
Come on man. Don’t abandon me here.
1983 BMW R80RT
1976 BMW R60/6
Still looking for a Honda CB77 Superhawk
User avatar
gspd
Posts: 1041
Joined: Tue Aug 03, 2010 8:04 pm

Re: Does not starts in gear

Post by gspd »

Seth -
I can't comment on your instructions and methods while at the same time trying to help cpazambrana.
He's a newbie at this and I'm trying to really simplify things for him.
2 people instructing him will only lead to confusion.
I will bow out and let you continue with him.
If it's not fixed soon, I'm at gspd@sympatico.ca if you need me.
I've been doing this kind of crap on airheads since 1975, so I may have picked up a few unusual habits on the way.
I just call them shortcuts.
In my defense, I've never had an electrical issue on any BMW that I could not correct in a reasonable timeframe (ie. efficiently).
There has been more time spent here talking about the problem he is having than it would actually take to fix it.
Mechanic from Hell
"I remember every raging second of it...
My bike was on fire, the road was on fire, and I was on fire.
It was the best ride ever!"
Seth
Posts: 275
Joined: Thu Aug 12, 2010 4:45 pm

Re: Does not starts in gear

Post by Seth »

Yes, GSPD
I don't want to give out wrong info.
I'll keep my mouth shut from now on.
User avatar
gspd
Posts: 1041
Joined: Tue Aug 03, 2010 8:04 pm

Re: Does not starts in gear

Post by gspd »

OK back to first base then,
(Nothing personal Seth, I'm just not a multi-tasker, it's highlighted on my resumé)

cpazambrana... please stick to the questions, no other tests (for now) please

You can leave your ignition off , I'll let you know when to turn it on.

Now to reiterate....

Connect the clip of the test light solidly to BATTERY POSITIVE terminal.

QUESTION #1: Does the brown clutch switch wire have GROUND?
QUESTION #2: Does the brown/yellow clutch switch wire have GROUND when you pull in the clutch?
your answer was yes, ground to both wires, clutch in or out, correct?

if correct continue to question 3

QUESTION #3:
Now do the same test with the bike in gear.
Do both wires still have ground? with the clutch in or out?

PS - A better quality pic of your wiring diagram won't hurt.
Mechanic from Hell
"I remember every raging second of it...
My bike was on fire, the road was on fire, and I was on fire.
It was the best ride ever!"
Post Reply