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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: manu on July 04, 2014, 06:59:56 AM
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Hi everyone,
I am new writing in this blog, although I am usual reader. Many posts have been REALLy helpful in the past. So, I am writing this time because my k100 83 is giving me an enormous headache, and I am wondering whether somebody had gone through similar troubles. Here is the issue:
I took my bike apart, with the naive idea of painting it (frame and fairings). After assembling her, I found weird electrical problems. The head lights, when on, cause the tachometer to flick up and down, neutral indication goes off, Horn works very faintly, and some other lights in the dashboard start flickering.
After reading some posts, everything indicates a bad ground, and perhaps that the starter motor is not grounding properly. So, I connected a ground wire to the starter motor main terminal, and all the problems despaired! I assumed then that the starter brushes weren't making good contact..and after a lot of unsuccessful cleanings, I decided to replace the brushes. BUT, the problem persists!!
Does anybody here knows what else can cause this problem? Would is be that there is an open circuit in my starter? If so, how can I test for that?
Hope you can help me, I am desperate to get back on the road!
Manuel
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Did you clean the inside of the starter motor's brush housing?
What's the condition of the commutator? Are there ridges worn in the path of the brushes? If so, it may need to be turned. Otherwise, clean the path where the brushes ride with some fine scotch bright or very fine emery paper so that it's bright, shiny copper. Go easy, here, just remove the surface oxidation.
After that, make sure there is no metal dust between the commutator segments.
A dead segment is possible, but you'd probably experience intermittent problems with the starter turning.
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greetings manu...
welcome to motobrick.com...
post up some photos... wanna see that new paint job...
j o
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I'm sure you checked that ALL your grounding locations have CLEAN UNPAINTED surfaces. So, I tend to agree that the starter commutator might need cleaning. Might try shooting it down with contact cleaner before a good scrub as any metal bits that get stuck the separation grooves can help things act up.
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Thanks guys! Indeed, I cleaned the ground points to bare metal. After reading your comments I open the starter again and did a thorough cleaning of the commutator contacts and body with contact cleaner. I check the resistance between contacts in the commutator, and I found very little resistance. Also, after assembling the unit, there is almost no resistance between the main terminal and the starter body. Is this normal?
I will send some pics of the paint job soon. Thanks again!
Manu
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........ after assembling the unit, there is almost no resistance between the main terminal and the starter body. Is this normal?
Yep, the starter motor has a fairly high current load(because of low resistance) when the starter motor is energized.
Also it's a good sign as the load shed relay ground path is thru that starter terminal.