Starter relay

[Martin]

You might want to look at this. battery isolator

[umichchris]

Ok so i checked the following:


- battery is new, voltage reads at 12.9v
- i installed a brand new starter relay (waste of $70)
- i double checked all the connections to the battery and starter and starter relay (all clean and tight)
- i installed an in-line kill switch in the event the start issue persisted (it did unfortunately, so now i have a quick & easy way to shut off power and finally stop the starter)


i have no idea what the issue is now. i cant ride the bike, no idea what to replace or fix next. the starter obviously works well, the relay is brand new, the battery is new...anyone have any ideas?





pics of the new in-line kill switch i installed:

[kennybobby]

Welded contacts shorting inside the ignition switch, the run/kill switch, and/or the start button.

i use the run/kill switch to apply or cut power after the ignition is turned on, to limit high-current interruptions within the ignition switch, which can cause arcing, pitting, welding, etc of the electrical contacts.  It's easier and cheaper to change a kill switch or relay than an ignition switch.

[Martin]

Starter buttons have been known to stick pull it apart and clean, but be careful not to loose any bits.
Regards Martin.

[Martin]

I hope you  remove the key from your switch when you leave the bike. Some joker could be tempted to make off with it leaving you with a dead bike. :yow
Regards Martin

[Motorhobo]

I assume you checked not just the voltage but also the load i.e. cold cranking amps on the battery. I had a battery once that test fine on voltage but showed no CCA on the load test, and I had continuous electrical weirdness until I got a new battery.

Anyway -- I had a start button fail due to corrosion once on a 95 that had spent too much time outside in the Pacific Northwest rain and damp. I didn't have your symptoms, though -- the bike just completely lost power. I ended up taking the right grip controls apart and jumping past the starter. Got it running but destroyed the switch and controls. Anyway, the point is that the starter button is one of the junctions between power and starter, and there is a history of this phenomenon -- see here:

http://www.motobrick.com/index.php/topic,5147.msg31679.html#msg31679


Last time you had the starter out, did you check the brushes? Is it possible this behavior result if the brushes were worn? If you're riding a 92, you'd probably want to replace those brushes anyway, so that might be a good place to go from here.

I remember something about the headlight grounding through the starter -- I have no idea whether that's relevant but unless someone comes up with an answer, everything's relevant.

http://www.motobrick.com/index.php/topic,8906.msg69765.html#msg69765

Keep us posted ---

[umichchris]

I hope you  remove the key from your switch when you leave the bike. Some joker could be tempted to make off with it leaving you with a dead bike. :yow
Regards Martin

She's locked up in my garage along with my M5 that i rarely drive, im guessing they'd steal the car first haha but definitely a good point on your end  :2thumbup:

[umichchris]

just had an idea, what if i ran a kill-switch to the starter? i know there's a positive & negative lead right on the exterior of the starter...what if i put an in-line kill switch on the negative terminal much like the one i installed for the battery isolation switch?


seemingly, the starter keeps running and the lights wont work because when the starter is activated the lighting functions are killed/shut off during that time (im guessing to provide the most amps possible to the starter to do its thing). if the starter isnt running or engaged, in theory the lights should then work properly again.


id have to flick another switch on/off when starting the bike, but it might just solve my problem. anyone have any thoughts to share on going that route?


thanks!

[Laitch]

anyone have any thoughts to share on going that route?

Perhaps your new relay is defective. Open the relay box and give the relay a couple of knocks with a screwdriver handle. You wouldn't be the first to have installed a defective part to replace a failing part. It all comes down to quality control, or karma.


You should sort out this problem and not try to bypass it until you understand what is inducing it.

[kioolt]

just had an idea, what if i ran a kill-switch to the starter? i know there's a positive & negative lead right on the exterior of the starter...what if i put an in-line kill switch on the negative terminal much like the one i installed for the battery isolation switch?


seemingly, the starter keeps running and the lights wont work because when the starter is activated the lighting functions are killed/shut off during that time (im guessing to provide the most amps possible to the starter to do its thing). if the starter isnt running or engaged, in theory the lights should then work properly again.


id have to flick another switch on/off when starting the bike, but it might just solve my problem. anyone have any thoughts to share on going that route?


thanks!

The starter does not have a positive and negative wire on it.  It only has a positive wire on it.  If you put the kill switch in it the headlight will go out.  You should find your REAL problem and fix it.

[jakgieger]

Reading this thread makes me think a grounding irregularity (assuming that the starter was checked thoroughly)... I and others have done this http://www.euromotoelectrics.com/Battery-Cable-Kit-BMW-K-BCK-5771317-p/bck-5771317.htm   

The ground points under the tank AND on the tranny should be checked as well.  This means separating all the terminals there, cleaning each surface, and tightening to spec w/a little copper antiseize.

I had a honda 4 wheeler that had this problem.  I finally bought an oversized (higher amp rating) starter relay...end of problem!

[The Mighty Gryphon]

Something I haven't seen answered in this thread so far: 

Is the starter relay being energized to make the starter run on?  Is there 12V on the starter relay coil when the starter motor is running on? 

You may want to install a 12V LED from the hot terminal of the starter relay coil that will light when the coil is being energized.  I would guess that the LED should only light when the start button is depressed.

Your problem may be somewhere upstream of the starter relay coil, not in the contacts.

[rbm]

I agree with Gryphon's analysis.  I'm questioning whether you have a defective ICU and not a defective relay.  Attaching a voltmeter to the Brown/Red wire on the starter relay coil will show whether power is cut to the relay once the engine fires up.  If not, then the ICU is suspect.


Correct behaviour should be that you see a potential at this point in the circuit when the start-enable voltage is present  (pull in the clutch or have it in neutral) and you press the start button.  It should remain present until the engine catches, at which point, the voltage should go away.  If it doesn't go away, then that indicates a failure of the ground-disabling circuit inside the ICU.

[umichchris]

Update:


after installing the new starter relay, the issue still persisted. on the off chance the relay came in the mail defective or stuck - i gave the relay a sharp rap on the upper left corner, reassembled things and gave the bike a start.....no more issues the past few days.


im still watching things closely, perhaps it was just a bad relay the entire time. ill follow-up if the issue resurfaces and there's a different fix needed. wish me luck!




again, thank you all for the information and help!!!

[Laitch]

im still watching things closely, perhaps it was just a bad relay the entire time.

It could be the relay's plug in the box. You could clean that and the original relay's terminals and try it the original again. Light corrosion could have been interfering. Normally I wouldn't recommend messing with something that works but it's slow around here right now and your checking this would help to keep my heart rate up. :giggles


Regardless, it's always good to have a spare starter relay. Thanks for the update.

[umichchris]

so, after a couple of days of worry-free operation the issue returned last Wednesday. I tapped the (brand new) starter relay and then the bike ran fine for three days until the issue returned on Saturday. Tapped the relay again and it ran fine for two more days until this morning while getting gas on the way to work and the issue returned again...this time i parked the bike for good in my garage until i can fully fix this thing.


im almost out of ideas and damn near ready to get rid of the bike. electrical issues are the worst, esp when you cant find the source. its like hunting an enemy you cant see/find.


here are my latest thoughts:
- battery low voltage/amps: the battery is brand new (purchase 2/16) and is/has been continually on a battery tender. i think the previous owner must have been battling these same issues but didnt tell me before i bought the bike...my reasoning is the battery is new and within all the paperwork her gave me i see receipts for two new starter relays. maybe the alternator (my car knowledge coming into play here) isnt charging the battery while the bike is running and the headlight/electrical system is draining all the amps during riding. when i test the battery the volts are strong but ill take the batter to the store and have them run a test for me...


- bad starter: maybe for some reason the starter wants to keep going as a result of it going bad? i checked the contacts and they are clean and tight


- my bike is a demon set forth on this soil to drive me mad: mayb less likely, but at this point a serious possibility.


all i want is a reliable bike to commute to work...im already cruising craigslist for another option haha


thanks in advance for your thoughts & suggestions!

[Laitch]

thanks in advance for your thoughts & suggestions!

Why don't you determine if the problem is related to the relay's connector in the box because tapping on the relay starts the bike?

[umichchris]

honestly, i think im just gna drop it off with a mechanic as soon as i can find a solid reputable independent bmw shop in LA i can trust it with...

[The Mighty Gryphon]

+1 on the Vermont mountain man's suggestion.   You may very likely have a bad connection in the relay socket.

Another thing that has been on my mind since I started following this thread is what is the voltage at the start relay's COIL connection when the start button is pushed?  I there a loose connection somewhere between the button and the coil that it activates?  This goes along with the possible socket issue and is where you should concentrate your search.

[The Mighty Gryphon]

I just looked at the wiring diagram for your bike.  The start relay circuit is one of the simplest on the entire bike.

There is a black and yellow wire that runs from the start button to the coil of the start relay.

The circuit has only three connection points:

The first is where the wire is connected to the button contact on the handlebar switch.

Next is the multi-pin connector for the right hand combination switch.  This connector is under the tank.

The last is where the wire connects to the terminal in the relay socket in the electrical box. 

If you want to nit pick, you can include the connection between the relay socket and the terminal on the bottom of the relay.

Check the resistance of these connections.  Any high resistance in this circuit will prevent the energizing of the start relay.  Wiggle them around to check for looseness.

[Elipten]

And clean all with deoxit cleaner.


Sent from my iPad using Tapatalk

[jjconeill]

I am having problems with my ignition relating to the starter relay. first I turn the key and no lights, than I give a little fist beat on the gas tank and the lights come on than power starter but lights go off tap the tank again and lights come on starter turns. took off gas tank turn key no lights tap on relay lights go on. replaced relay with new, and does the same thing. thinking I have a loose wire from ignition switch, will check that molex connector ion Saturday when the weather warms her in Chicago area. Any suggestions would be great. Love my K75 but too many problems after one year owning. 1987 paid 1200 put 2000 into it with a lot of help from a not so smart dealer trying to fixing it. new sending unit, new fuel pump, than oh it was a relay. Thanks again.

[umichchris]

honestly, i think im just gna drop it off with a mechanic as soon as i can find a solid reputable independent bmw shop in LA i can trust it with...

never got this figured out. parked in the back of the garage. gave up on it lol


anyone in the LA area want to pick up a K100 very reasonably priced?

[The Mighty Gryphon]

Under the tank on the top frame tube there is a cluster of Brown wires connected to the frame.  On the side of the engine case above the shifter is another screw with some brown and black wires.

Have you cleaned them so they are nice and shiny as well as the spots under them on the frame and engine?  Bad grounds can create all sorts of strange problems.

[The Mighty Gryphon]

How old is your battery?  Is it fully charged?