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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: kaleb on November 10, 2015, 10:56:44 AM
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Hi
I had some starter issues last week, intermittent failure to start despite full battery.
Another symptom which seemed to be connected was that sometimes the engine starting would cause the headlight to go out.
I had a look through here and found that the rocking backwards and releasing clutch generally worked, and if the lights (also affected turn signals) went out with the engine starting then I'd just kill it, do the rocking again and soon enough it would start AND the lights would work. Once I'd got both the engine and the electrics working, it would all run fine until I parked up when the problems might or might not recur.
After a few days of this it simply died and wouldn't start at all.
So I took the starter motor out, dissembled it and cleaned the commutator (put it in a drill and held a methylated spirits soaked rag against em til the copper was (almost) shiny again). I noticed that one of the starter brushes was quite abit shorter than the other, maybe 6mm against the other's 10. But I didn't have any replacements (yet!) so I just made a note of that and put it all together again.
On reassembly everything worked, starting AND electrics.
It's a few days later now, and the starter issue is creeping back, only not as frequently, as is the lights issue. It seems quicker to solve now, with the rearwards rocking, but still something is clearly suboptimal in there.
So I'm gonna order some new starter brushes and install those. I've read on here that damaged or dirty brushes can cause problems with the Load Shedding Relay which in turn can affect the bike's general electrics.
Am I on the right track?!
Thanks for any advice. Forgive the perhaps obvious questions - this is the first motorvehicle I've ever owned, let alone interfered with, and I'd never heard of a starter motor until two weeks ago!
Cheers
Kaleb
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Forgot to mention, it is a '92 K75 with 64k on the clock. There were no markings on the starter motor casing so I'm guessing it hadn't been fiddled with before...
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How old is your battery, Kaleb?
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According to the previous owner (I bought the bike August this year) it was replaced in August 2014. It looks pretty 'new', and if memory serves it was made by Varta, a cheapy one I think
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Periodically cleaning the starter is a good thing to do on these bikes. Replace the brushes when you can. Also ensure the starter is well grounded.
Tom
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Thank you, Tom.
My new brush set arrived yesterday and I took it all apart again. Interestingly (?!) the commutators that I cleaned very well just two weeks ago looked filthy black again. Presumably because of the knackered brushes...
Cleaned the commutator again (with very fine sandpaper this time til it looked new), got the new brushes in and bingo, it looks like everything works again, including the electrics.
So thanks.
I also sanded down the main earth from battery to frame which was pretty grubby and may have been interfering with the electrics generally.
I couldn't see anything that looked like a ground/earth coming off the starter motor, what did you mean by 'well grounded'?
Gonna go for a ride now and hope the headlight stays on!
Cheers
Kaleb
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I meant to make sure and clean the mounting surface at the back of the starter. I use a copper based anti-seize in the two starter bolts to help ensure a good ground.
Enjoy your ride! It's raining like crazy here.
Tom
Thank you, Tom,
[snip]
I couldn't see anything that looked like a ground/earth coming off the starter motor, what did you mean by 'well grounded'?
Gonna go for a ride now and hope the headlight stays on!
Cheers
Kaleb
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Ah! Yes of course it is grounded by the bolts, that hadn't occurred to me, although I did clean those bolts off anyway. Copper based anti-seize is a bright idea. Thanks again. K
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The anti-seize isn't necessary, ensuring the bolts are clean is sufficient.
Tom
Ah! Yes of course it is grounded by the bolts, that hadn't occurred to me, although I did clean those bolts off anyway. Copper based anti-seize is a bright idea. Thanks again. K
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Goes against the grain but don't do too much to the commutator. If its rough it wears out the brushes double quick. It needs a black carbon layer to keep it smooth to not wear the brushes [creating excess carbon dust that can cause problems] and also provides a good electrical connection. When you went back in the second time that black was worn from the brushes. Resist temptation to sand the commutator again and the brushes will last longer.
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I have 150,000 K's ( 90,000 Miles ) on my 92 S. I service it myself, gets done by the book, to the point of being anal. But I have never looked at my starter, should I be pulling it apart for cleaning. Or should I leave well enough alone, I have never had any starting issues. Your thoughts.
Regards Martin
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I have 150,000 K's ( 90,000 Miles ) on my 92 S. I service it myself, gets done by the book, to the point of being anal. But I have never looked at my starter, should I be pulling it apart for cleaning. Or should I leave well enough alone, I have never had any starting issues. Your thoughts.
Regards Martin
I would definitely open it up to clean and inspect the brushes. I put a tiny bit of grease on the seal and where there's metal to metal contact
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At the mileage I have should I have brushes on hand as a precaution. And a bit of a how long is a piece of string question, what sort of mileage have other riders getting out of their brushes. I am pulling my bikes fairing off this weekend to repair damage might check the starter at the same time, but a bit reluctant as I don't have brushes on hand. Is there an after market source for the brushes.
Thanks Martin.
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Is there an after market source for the brushes.
An aftermarket kit is mentioned in this thread, Martin.
http://www.motobrick.com/index.php/topic,7704.msg55592.html#msg55592
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Laitch I looked at the Euromoto Electrics brush set up and did read, your post on your experience. I thought they sounded a bit dodgy and a bit of a hassle. But in saying that I presume they have your recommendation. So I will probably go in that direction. I did find a supplier of brushes only, but will not ship to OZ.
Thanks Martin.
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That was Tim's post, Martin, but based on Tim's experience I'd buy theirs if I thought I needed them.
You live in a beautiful place, Martin, but it's not a consumer's paradise, is it? Of course, that can be both economical and stimulating when a repair requires an orgy of invention, I suppose.
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Laitch you are right it's a beautiful country, and we do have to get a bit inventive, if we want to avoid the rip offs. But I suppose that's part of the fun, seeing if you can outsmart the mongrels.
Thanks Martin.
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Martin, check with an electrics shop (either automotive or otherwise) and see if they can't do you up a set of brushes to spec. I will be doing that for my alternator. The starter looks fine but the alternator, with around 65,000 miles on the clock, is starting to show significant wear. I hope to ride to the east coast this late Spring and I would do this brush service first. Not sure of the wear rate on these things but why risk it.
Good luck.
PS - the supply chain issue must be a bit of a bear at times for you guys. I sit in the middle of the distribution hub for Canada and can get stuff out of the US in days....not bragging, simply comparing. Patience is a virtue....and for everything else there is FEDEX!
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check with an electrics shop (either automotive or otherwise) and see if they can't do you up a set of brushes to spec. I will be doing that for my alternator.-------- Not sure of the wear rate on these things but why risk it.
Get the closest match, and shape them yourself....all you need is a flat surface and a sheet emery paper.
(done it many times on alt. brushes to different cars).
About wear rate....did change them on my oldest K when it had just above 200K km on the odo.
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Just an update/summary on this (solved) problem.
Initially my starter became temperamental; I could get it to work by rocking the bike back and forth in gear (which causes a minor spin of the starter, resetting the contacts for a next attempt)
When that 'solution' stopped working, I dissembled the starter and cleaned the commutator (the copper strips) using a meth soaked rag, reassembled it and everything worked as it should.
I noted then that one of the brushes was considerably more worn than the other, so I ordered a new set.
By the time the new brushes had arrived, a new set of problems was manifesting: again an intermittent failure to start, but this time coupled with strange electrical behaviour: a successful start often as not would cause the ancillary electrics (headlights, indicators, horn) to fail. I'd have to kill and restart until both worked, sometimes the 'rocking' method would affect the outcome, but basically it was a right ball-ache trying to get both engine and lights working. Ultimately it failed at night and I had to limp home with the hazards on (which still worked despite turn signals not working individually).
Armed with new brushes and a little reading about the Load Shed Relay (which apparently drains ancillary power during starting to make sufficient current available to turn the starter motor - hence the lights go out momentarily on operation of the starter button), I disassembled the starter again, ill-advisedly 'cleaned' the dirty-again commutator again this time using fine sandpaper, installed the new brushes, cleaned up the grounding (earth) bolts on the starter motor casing, and also sanded down the main battery earth connection when I was putting it all back together.
The outcome of this work was perfect operation of starter and all electrics since then (about 4000 miles).
Conclusion:
worn starter brushes cause not only starting problems, but less intuitively can confuse the Load Shed Relay causing diverse, intermittent electrical problems
Thanks everybody for the help and advice! It is very satisfying to learn things: as I've said, this is the first motorvehicle I've ever owned... Cheers! K
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Good outcome.....but, you shouldn't use sandpaper on the commutator,,,your new brushes gonna wear out
much faster....use a eraser to clean the commutator.
When having to less contact area when changing to new brushes...it's better and easier to adapt the brushes,
but they usually wear in quickly to the commutator.
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A mate is going to lend me a starter when I get around to the rebuild. And I will follow Inges suggestion and make my own brushes. Kris thanks for the input, UK, US and Canada have a lot more choice of products and services. But it can be fun trying to get around the lack of parts. I have a pretty good back up, a mate has a bit of a collection of K bikes. If he won't sell me the part, he will lend it to me while I source or repair it. Helps a lot, but I'm still of the road awaiting a fairing repaint ( No Spare ).
Thanks to all Martin.
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Just a note that 9 months after the final post to this thread I found it describing my symptoms precisely . Kudos to you all for documenting this full circle :clap: