Bike Won't Shut Off !!

[Bob_Roller]

I took the bike into the emissions test station today, as part of the annual registration process.

I went to shut the engine down, so they could put the collectors behind the exhaust, and when I turned the key off, the bike continued to run, the headlight went out, but it still ran, had to shut it off with the kill switch.

Looks like I've got an ignition switch replacement now.

[Rob Valdez 79 R65]

You can have my original switch, if you want to try and clean up the buggered threads on it.  That is why I replaced it.

[Bob_Roller]

Thanks Rob, but I just got my dividend refund check from Citibank today, charging everything I could over the last 7 years finally paid off.

Looks like I'll give Chicago BMW a try, ignition switch, and a bunch of little nit-noid parts that need replacing.

On the bright side, the bike passed emissions with no problem this year, less than 40% of what the pollutant levels were last year before the carb rebuild, though the carbs need a bit of 'tweaking' to get them perfect, getting a high idle after the bike gets hot.

[Jon_P]

we dont have to test our bikes here so i never had to. that exhaust sniffer can it tell if your running rich or lean??? that would be kind of cool???

[Bob_Roller]

The read out is for unburned hydrocarbons, and carbon monoxide in %.

All of this is done at idle, I kinda wished that they would run the bike on the dynomometer that is used for vehicles without the OBD2 test connector.

[Bob_Roller]

Did some trouble shooting today, and the ignition switch is not the problem.

I removed all 4 wires from the switch, and no help.

Curious thing, is that if I remove the ground cable from the battery for a second or two, the problem goes away, until you turn the ignition switch back on.

I checked with Rob Valdez about the operation of the hazard flasher system, and it is not supposed to work with the switch off, mine does.

There's a large diode in the power wire for the system, if it fails in the mode of allowing power to flow in both directions, it may be my problem.

Have to wait a few days to get back to it again, as today is the last day of my 'weekend', and I expect to work double shifts the next couple of days.

[nhmaf]

Sounds like you might be on a right track Bob.   One other thing to possibly simplify the process - does it behave this same way with the tachometer disconnected ?

Have to take a look-see at the wiring diagrams again...

[Bob_Roller]

Has a burst of enthusiasm this evening, went out and removed the tank.

Disconnected the electrical connector that interfaces the 4 way flasher system to the rest of the wiring harness, and the problem went away.

Tested the suspect diode, and it has continuity in both directions.

I put the two solderless terminals that slide onto the diode together, and it gives the same fault as when the diode is installed.

So problem solved !

Diode is about $10 at Chicago BMW, a lot cheaper than a $100 ignition switch !!!

 Took the plastic case apart on the diode, and it is a common diode 1N4004, that you can get at a consumer electronics shop for about a $1 each.

About a minute or two of desoldering, and soldering and it will be done.

The diode itself is split in two lengthwise.

[montmil]

Has a burst of enthusiasm this evening...

One of those "inspired moments" that definitely worked. Good on ya! Some of my "moments" ain't so...

[nhmaf]

Bob,

Good job on your diagnosis - it is amazing how a simple thing like a bad diode can screw up your day !

Is your 4-way flasher system a BMW option, or is it a 3rd party product ?
Part number ??
I have thought of possibly adding such a feature to other Beemers, I've owned, though now I only have
the R65 to mess with.   I think that I may be adding some dual Fiamms this summer..

Thanks !

[Bob_Roller]

The kit is a factory BMW kit, no longer available, I got mine on eBay about 3 years ago for $35 plus $15 shipping from Germany.

The trouble shooting wasn't too difficult, after disconnecting the ignition switch and still having the problem, it was time to look at the wiring diagram, until I found the supplemental wiring diagram from the 4 way kit, there was no way to get power to the ignition system with the ignition switch disconnected.

[nhmaf]

Yes, I was scratching my head over that when you first posted that you had the problem even with the ignition switch out - according to the wiring
diagram it would be impossible, but I hadn't counted on you and Rob with your fancy-schmancy emergency flashers option !
 

[Rob Valdez 79 R65]

Yeah, it is SO COOL!




(just ignore the cat box!)