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Discussion Starter · #1 ·
Hi guys.
I bought a 2000 650 GS a few month ago and it has alway had starting issues but it's got to the point where I need to sort it as it's totally unreliable. I've checked battery and changed spark plug but I noticed there was no spark when I press the button with the spark plug out. Shouldn't you normally see a spark and if so would it just be a case of getting a new relay/switch that leads to spark plug? Tia.
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Silly question, when you say no spark at plug when ' out' - plug is grounded/earthed ?
Plug leads, caps can corrode, damp runs along leads, check you have voltage to coil - LV feed, then work back, few micro switches in circuit that can play up, side , centre stand, clutch (so you don't start bike in gear) kill switch /starter is another worth checking, contacts corrode, wear.
 

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Discussion Starter · #3 ·
neutral switch. Really struggled to get the plastic neutral switch out as I couldn't get a spanner or socket on it and, being made of plastic, I was starting to round it off. I shorted the side stand switch which made no difference. Obviously checked the battery. With the kill switch on there is no power to the bike, so I don't think it's that. When I was putting bike back together, seated what I think is the starter relay ( under the middle panel, in front of the battery) probably and then it starts. I let her run till the fan kicked in then turned her off. She started later on in the evening. Today, nothing again. Also the neutral light I'd staying on now and only goes off if you put it in gear and lower the side stand with clutch in! Wtf?! And yes, I grounded the spark plug on the engine block when trying to start. I'm a bit down hearted as I spoke to a independent BMW Specialist and he said it can get very expensive with old electrics. Thanks again for your reply.
 

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There's a good circuit diagram on the Crossroadz site here:


The fact that your neutral light is doing strange things when you activate other switches suggests maybe a fault with one of those components or connections. Maybe the earth connection for the clutch and side stand switches - not sure where it is though. Also , maybe one of the diodes is failing?

The starter circuit needs neutral or clutch in and the motronic (which is needed to run the engine) requires either side stand up OR sides stand down PLUS neutral.

What are your symptoms - is it turning over but not catching?

To bypass the side stand switch, you can connect all three wires together. You could check resistance to the negative battery terminal from those three joined wires to make sure the earth connection is good. If your earth is good and you've joined those three wires, the motronic relay should be on whenever the ignition is on (and kill switch set to run).

I had similar intermittent problems with my bike eventually traced to side stand switch wearing out.

Good luck.
Buzz.
 

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Discussion Starter · #11 ·
There's a good circuit diagram on the Crossroadz site here:


The fact that your neutral light is doing strange things when you activate other switches suggests maybe a fault with one of those components or connections. Maybe the earth connection for the clutch and side stand switches - not sure where it is though. Also , maybe one of the diodes is failing?

The starter circuit needs neutral or clutch in and the motronic (which is needed to run the engine) requires either side stand up OR sides stand down PLUS neutral.

What are your symptoms - is it turning over but not catching?

To bypass the side stand switch, you can connect all three wires together. You could check resistance to the negative battery terminal from those three joined wires to make sure the earth connection is good. If your earth is good and you've joined those three wires, the motronic relay should be on whenever the ignition is on (and kill switch set to run).

I had similar intermittent problems with my bike eventually traced to side stand switch wearing out.

Good luck.
Buzz.
Thanks for your reply Buzz. Yes, the engine is turning over but not catching. It doesn't seem to be sparking. I thought it was the side stand. I did the get you home bodge (stuffing a bit of rolled up tin foil in the connection socket so it wasn't permanent) and that made no difference. Maybe I need to try again with a more permanent effort. The actual switch at the stand is well loose. I think it's missing a circlip. Could this cause the problem. There's about 5 mm of movement, up and down. Thanks again.
 

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I think the kill switch is in the starter and motronic circuit so it wouldn't turn over if it was faulty.
The items in the motronic circuit are
-kill switch
-motronic relay (which could fail)
-side stand switch (up goes direct to earth, down also needs neutral switch to make to reach earth)
-A diode.

If you join all three wires that go to the ss switch it would rule out the ss switch, a diode and neutral switch all in one go.
If it still doesn't start like that, I'd be looking at the motronic relay. (Only need to join Brown/violet to Brown but easy to do all three and won't cause issues).

I think you can swap the motronic and load relief relay to see if it'll catch. Without the load relief relay, a bunch of stuff won't work but it might start - I can't remember for sure but worth a try.

The relays are often different colours but are basically the same. See the middle picture at the bottom of this Crossroadz page:


Buzz.
 

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Discussion Starter · #14 · (Edited)
Hi guys.
A quick update. Bought a multimeter and had another look at bike today. I think it's my coil that's fubared. I have 12v getting to the coil. I've checked the primary of the coil and I'm only getting 0.7 ohms testing from the outer two prongs and nothing Going from the Outer prong to the spark plug socket. Also I'm getting no voltage when the coil is plugged in, ignition on, at the spark plug socket. I noticed lots of corrosion where the coil fastens to the bike and there is also a crack here. I'm wondering if that mat have let water in? I'm a complete novice with electrics, does what I've said sound right? And also, does having 12 v at this wiring connector rule out issues with side stand/neutral switches etc? Tia.
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I've got different coils and haven't had a fault with them so no experience.
Haynes says to measure primary between the primary connection and a mounting bolt (earth) - expect 0.45-0.55 ohms.
To measure secondary it says put probes on same bolt and spark plug connection. There's no value for the reading on the GS but the Funduro and ST are listed at 6-14kohms.

Buzz
 

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Discussion Starter · #20 ·
Apologies, haven't checked this for a while. I bought a (tested) 2nd hand coil off flea bay which had a lead attached. Still same problem. I'm not good with electrics and pretty close to giving up. I did notice this plug without a home under the seat. Anyone know what it is?
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