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Starter Cleaning and Repair

What Do You Mean, “It Won’t Start?”

By Don Hamblin

A whole year or so of putting up with, “it won’t start when it’s hot,” had finally gotten the best of me. I’d changed batteries; fuel filters, insulation under the tank, fuel lines, and even brands of gas. Everyone I talked to had a different idea. I’d even learned a bunch of technical stuff (some that I even understood) about fuel injection and fuel flow. Dealers would shake their heads and mumble, and friends would say, “why’s he holding us up?”

Finally at the Return to Shilo rally, I asked Rick from Motorrad Electrick. Less than twenty seconds into my lament he interrupted me and finished my story. Even telling me that I have an ’85 or ’86 K100 with over forty thousand miles! My reply was, “OK, how do I fix it. And how much is this going to cost me?”

Rick tells me that it’s just time to service my starter. Service my starter? Along with every other expensive service for the K bike, now I get to service my starter? Come on, isn’t there an easier way to fix this problem? Rick tells me yes, I could buy a new relay (expensive, and he didn’t think that was the real problem), or a new starter (if I really wanted to waste a bunch of money right off the bat). It’s just that the starter needs to be cleaned every twenty thousand miles or so. In other words, not really taking any better care of my starter in its twenty’s than I did my own body, is causing me troubles in its middle/late forties (motorcycle mid-life crisis!)


There’s a reason why I’m not a technical director or anything like that; I’d rather ride than wrench – that sometimes even includes washing. I’ve also broken as many things in my lifetime as I’ve fixed. So, taking the bull by the tail, I called my new friend, John Zibell, and asked to use his garage and motorcycle lift. There’s nothing wrong with being lazy! John tells me, “sure, I’ve had to do the same thing to Jean’s K75. Bring it on over.”

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Using the lift made all the difference in the world. Everything’s right at eye level. I love it! Remove the side panels, lift out the storage tray and computer, tilt up the battery, and there’s the starter. A couple of bolts later and you can pull the thing out. (A little note here: It’s a little more complicated than this, but any shop manual will “paint by numbers” you through the whole removal. Oh yeah, if you’ll remember to let the bike completely cool, the starter slides right out – if not, a little prying is in order.)

Next you should set the starter in a vice (no, don’t clamp it, just set it between the jaws – it’s really too expensive a Japanese made BMW part to destroy like that) to steady while taking it apart. Keep real close track of the screws and stuff during disassembly so that you can put them all back again. The brushes are real important.


Now you’ll be amazed at just how dirty the commutator is (that’s the “copper colored” part near one end). That black “stuff” is your problem. A little brake cleaner should remove it all. If not, Rick had suggested using an ink eraser to make it really shine. That’s it! Putting it back together is really a lot easier when all that “crud” had been dumped out of the case. Just “reverse” the disassembly process.


John suggested that we test it (you know, hook it up to the battery) and see if it still works. It did! We smile and start sticking all that stuff back on the bike. The acid test was to try it on the bike. Again it worked. That’s it. An hour and a half on a Saturday afternoon, and faith is restored.

A quick stop for gas on the way home and no one said, “why’s he holding us up?”

Starter Cleaning Tips

By Eric Eason
November 2001

Recently my 1984 K100RS has been behaving a little poorly, first I thought it was a flat battery as it wouldn’t start and the instrument lights were very dim.

However it bump started easily and didn’t give any more problems for a while, then it did it again and after checking the battery I noticed one of the terminal bolts was a little loose, then fine again for another week…

Yesterday it did it again and I knew the battery and the terminals were fine even though it was giving all the symptoms of a flat battery, clicking relay and no or dull instrument lights, bumped it in 3rd again, (this time on the flat, best if you take off the left pannier off first).

At home I thought about cleaning the ignition switch but then decided to pull the starter from my other k, which was without battery, and try that, started fine!

Now this is one of those things i’ve been avoiding but in the end it only took about an hour and very easy to do, here are a few hints.

  1. Removing the battery is easy if you twist it 45 degrees and then use the edge of the battery to force back the plastic mudguard so you can finish the turn to 90 degrees, now it should pull out straight up.
  2. Leave the battery tray in, after removing the 2 starter mounting screws slide the starter back an inch to get to the plastic cover and the 10 mm nut on the terminal, (getting the starter back is tricky if it’s never been out before, you just have to keep on jiggling it while pulling, it comes out eventually).
  3. The 2 long screws holding the starter together are in very tight, I put it in a vice and used a phillips bit on an extension in a 3/8 socket wrench to crack them.
  4. Once they are out it is easy to slide off the end cap and gently free the brushes and holder from the rotor, be careful pulling off the endcap as it is connected to the brushes by a wire and you don’t want to pull that off.

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