Post by: dougo on October 06, 2019, 05:33:53 PM
Post by: johnny on October 06, 2019, 05:38:27 PM
poast that picture and the link to that thread here...
j o
Post by: dougo on October 06, 2019, 06:05:03 PM
Post by: johnny on October 06, 2019, 06:53:46 PM
then we caint help you... (http://www.motobrick.com/index.php/topic,7704.0.html)
41mqiOkcALL._AC_SY400_.jpg (22.32 kB . 393x400 - viewed 1014 times) diode_relay.jpg (8.17 kB . 237x200 - viewed 944 times)better ping rbm... looks like some need the resistor some dont...
j o
Post by: daveson on October 06, 2019, 09:38:06 PM
I hope you get this to work. It will be a big bonus if it does.
Post by: rbm on October 06, 2019, 10:25:40 PM
Post by: dougo on October 07, 2019, 08:19:40 PM
I seem to hear the relay click when I press the starter button. And I hear the fuel pump start to run as well.
I printed your diagram and used it while soldering....
Daveson I'll have to do a continuity check when I get the chance , thanks for that.
Johnny thank you for putting the example up.
I'll keep everyone posted. Watching the Dodgers and nationals right now though.
Post by: johnny on October 07, 2019, 09:34:03 PM
look dougo... poast a photo of the diode and the install for gawdssakes...
j o
Post by: dougo on October 07, 2019, 10:14:00 PM
Post by: rbm on October 08, 2019, 04:55:58 AM
Rbm, when you look at the physical diode, is the line on the casing at the cathode end? If so then it is right.. If not I'll have to get out my soldering iron again.Yes, the line on the diode case corresponds to the cathode (line) on the schematic symbol. When looking at the symbol, the symbol resembles an arrow and remember that current flows freely in the direction of the arrow. In this circuit, you want the diode to normally resist the natural flow of current from +ve to -ve.
Post by: dougo on October 12, 2019, 03:05:21 PM
There is power to and from the starter switch, the fuel pump is priming when you hit the switch. Still researching....
Pictures would be redundant at this point...
Post by: dougo on October 12, 2019, 05:23:32 PM
Post by: daveson on October 12, 2019, 05:54:34 PM
Post by: dougo on October 12, 2019, 05:59:15 PM
Post by: daveson on October 12, 2019, 06:11:25 PM
Do you have 12 volts between battery positive and 85?
Post by: Laitch on October 12, 2019, 07:46:17 PM
After some research and bridging the starter connections to get the engine to turn over with no luck starting and running the engine, it is my guess that I fried the ecu or some other electronic part necessary for the bike to start and run...There are function tests for both the fuel injection control unit and the ignition control unit within the troubleshooting guide pdf in the Repair Guidance section's No Start category. Download the document and scroll down to find them.
Post by: dougo on October 12, 2019, 09:34:11 PM
Post by: bmwcyclist on November 26, 2019, 09:59:22 PM
It appears to have a diode in the diagram.
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Would be cheaper, and up to 130 amp from the stock 70.
https://www.euromotoelectrics.com/Relay-BMW-61-36-9-198-302-p/rel-302.htm
.
Post by: rbm on November 27, 2019, 12:37:19 AM
Post by: Past-my-Prime on November 27, 2019, 06:26:54 PM
Don't spare my feelings!!
Post by: rbm on November 27, 2019, 11:35:40 PM
Post by: enb54 on May 20, 2021, 02:53:12 PM
Post by: bmwcyclist on May 20, 2021, 02:58:22 PM
This was my final solution :
http://www.motobrick.com/index.php?topic=7704.msg124912#msg124912
Post by: enb54 on May 20, 2021, 08:56:27 PM
20210520_132135[1].jpg (78.35 kB . 768x576 - viewed 738 times)Got any good tips about replacing those e-clips at the bottom rear of the fuel tank? Not too thrilled with the BMW originals...
Post by: Laitch on May 20, 2021, 10:30:45 PM
I found that once they start going you will continue to replace them.In the post sited above, what happened between Step 3—the replacement of the ICU, and Step 4—the addition of the second relay? Did another OEM relay fail after you replaced the ICU?
http://www.motobrick.com/index.php?topic=7704.msg124912#msg124912
Post by: Martin on May 20, 2021, 10:46:07 PM
Regards Martin.
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Post by: enb54 on May 20, 2021, 11:59:32 PM
Post by: The Mighty Gryphon on May 21, 2021, 07:13:48 AM
The cable ties also work on the clips that hold the seat, especially the clip thar holds the hinge pin at the rear of the seat.
Post by: bmwcyclist on May 21, 2021, 09:02:29 AM
In the post sited above, what happened between Step 3—the replacement of the ICU, and Step 4—the addition of the second relay? Did another OEM relay fail after you replaced the ICU?
After the 2-relay setup was installed I have had no further problems. Back to being a great trustworthy K75.
Post by: Laitch on May 21, 2021, 09:07:34 AM
After the 2-relay setup was installed I have had no further problems. Back to being a great trustworthy K75.That I understand. What I'm trying to understand is how you are certain that failure of the relay wasn't caused by a faulty ICU.
Post by: bmwcyclist on May 21, 2021, 09:10:25 AM
That I understand. What I'm trying to understand is how you are certain that failure of the relay wasn't caused by a faulty ICU.
The relays were failing on the HOT side.
Post by: enb54 on May 21, 2021, 09:46:24 AM
Post by: daveson on May 21, 2021, 10:43:32 AM
The relays were failing on the HOT side.
Thank you for posting your interesting and workable solution.
Are you saying the failure was due to the Volts too low on the hot side? Was the cause found, like why doesn't it happen with your other brick using a weak battery? Like maybe the resistance is higher on the trouble one?
Post by: bmwcyclist on May 21, 2021, 11:23:47 AM
Thank you for posting your interesting and workable solution.
Are you saying the failure was due to the Volts too low on the hot side? Was the cause found, like why doesn't it happen with your other brick using a weak battery? Like maybe the resistance is higher on the trouble one?
That was an answer to a specific question about the ICU.
I own two K75, and ride with close friends that bring the number up to 5. Only the one bike ever had relay issues. It would eat a relay about every two weeks or so.
I read all of the threads and followed all of the advice:
1. checked battery power
2. replaced the battery
3. replaced the battery again
4. Replaced all related power cables
5. Added additional ground cable
6. Replaced the starter (twice), one used, one new
7. Replaced the starter switch
8. stock and aftermarket relays
None of this solved the issue. I installed the two relay system and it has worked perfect since.
Post by: daveson on May 21, 2021, 09:24:35 PM
While the other suggestions seem to be electrical, I imagined a mechanical reason that shows up as electrical, say friction from a tight bearing for example, resulting in a Voltage drop while cranking being lower than normal.
So I was wondering if one of the tests you did was checking Voltage drop across the battery while cranking, using the same battery with both of your bricks. That test (or an Amp test) might even set your two relay brick apart from the other four.
Just a thought.
Post by: enb54 on May 22, 2021, 02:31:24 PM
I found that once they start going you will continue to replace them.
This was my final solution :
http://www.motobrick.com/index.php?topic=7704.msg124912#msg124912
After reading through that thread pretty thoroughly, I gather that you use the K75 starter relay to operate the F650GS relay to switch the high current required by the starter motor? Presumably because by itself the F650GS relay caused other electronics to misbehave? I will keep that in mind if I have problems again, but will likely get a high current relay that is less expensive than that gold plated solid platinum $$$ BMW part. The WM686 from johnny's post is only about $10 and it handles 100 A...
Thanks in advance for sharing your efforts...
Post by: rbm on May 22, 2021, 02:41:34 PM
It's possible that another relay could substitute for the OEM relay in this configuration if it has the same coil specs as the OEM relay. Do you know how much current is demanded by the F650GS starter relay? The OEM relay demands about 275mA @12V.
The best solution would be able to find an aftermarket relay that was speced exactly as the OEM relay yet was the correct physical size, cheap to buy and easily obtainable (and didn't have that nasty habit of oscillating when the battery voltage is low).
Update: I did some looking around and found a TE Connectivity Potter Brumfield high power automotive relay very similar in appearance to the F650GS relay. This is a Potter Brumfield 2-1414939-2 (https://www.digikey.ca/en/products/detail/te-connectivity-potter-brumfield-relays/2-1414939-2/3043603). The 12V model has a 37 Ohm coil. I measured the DC resistance of the coil of a BMW K100 starter relay I had in my spares box and it measures 43.5 Ohms. Obviously, the PB relay will require greater current to operate than the BMW relay. The BMW relay uses a freewheeling diode as a snubber whereas the PB relay uses a resistor. Either or both of these differences might well be why the ICU failed for bmwcyclist.
Post by: daveson on May 22, 2021, 03:50:06 PM
Is there any merit in the thought that excessive mechanical resistance could drop the cranking Voltage to a point that causes the relay to stick? I'm trying to understand why some bricks don't have the problem even with weak batteries. Or maybe it has to be just the right amount of flat to cause oscillating.
Post by: rbm on May 22, 2021, 04:24:31 PM
The entire motorcycle electrical system experiences the droop, including the starter relay coil and the following cycle of events will occur should this happen. If the droop across the starter relay coil falls below its designed "Must Release" voltage, the relay will disengage, the starter motor will stop, the battery terminal voltage will recover to above the designed "Must Operate" voltage, the starter relay will engage, the starter motor will stall, the battery voltage will droop, the starter relay will disengage, the starter relay will disengage, and so on and so forth until the starter relay contacts weld themselves together because of the heat generated.
Variation in lots of variables will cause different responses. The Must Release and Must Operate voltages vary from relay to relay because of manufacturing differences, voltage drop across the motorcycle electrical system will vary, the mechanical torque the starter motor must overcome and deliver to rotate the engine will vary, the internal resistance of an unhealthy battery will vary, and so on.
It's complex. My K75 has never welded a starter relay ever, even with a very unhealthy battery installed. I've been lucky I guess.
Post by: Laitch on May 22, 2021, 05:37:46 PM
My K75 has never welded a starter relay ever, even with a very unhealthy battery installed. I've been lucky I guess.My moto's starter relay hasn't capitulated in the 60K miles I've own it. The battery is eight years old and has never been maintained on a trickle-charger. I'd better get shopping. :laughing4-giggles: The durability of some starter relays might be attributable to being in a well-tuned moto and that is cranked with a firm thumb on the starter button, and that isn't cranked for more than three or four seconds at a time.