Hey friends,
My usually dead reliable 1985 K100RS is giving me trouble in the middle of a touring trip and I'm hoping you guys can help me out.
Here's what happened: About 300 miles into my day I was pulling into a small town. As I slowed down coming into town I noticed that my starter was coming on intermittently. I'm not sure if it started right then, or if it had been doing it a while and it was only when I showed down that I noticed. I pulled into a parking lot to check it out.
When I tried to start the bike again, the dashboard lights came on normally. Pushing the starter button activated the fuel pump but I got nothing from the starter. Bad starter relay seemed like a good guess, so I replaced that and the load shed relay too, just in case, congratulating myself for carrying spares. But it had no effect. Starter button still activated the fuel pump, but not the starter. I did confirm the starter relay is clicking. That was the end of my power of diagnosis. Isn't it amazing how much harder it is to think clearly with a broken bike by the side of the road than comfortably in your home shop?
I figured I might have killed my starter, so I tried bump starting the bike. It worked! Yay! Sunset was approaching fast and I was starting to think it might be an overly interesting evening. By the way, bump starting was way easier than I expected.
So I continued my ride thinking I'd killed my starter. But then I noticed that my headlight was out and none of my switchgear was working properly. No horn. Pushing either turn signal button or the cancel button makes all four turn signals and the dash light flash once. Other than that the bike rode perfectly.
During the rest of my ride to tonight's hotel, I started wondering if one of the switchgear connections to the loom might have come loose. When I got here I checked that. Nope, they're both tight. Wiggling them made no difference.
So, any thoughts about what might be going on? I'm hoping you guys might have an idea that can get this trip back on track. If not, I'm bump starting and heading for home as quickly as possible tomorrow morning. I have a pretty good selection of tools to try ideas, but no multimeter (Damn! That's a mistake I won't make again).
What do you think?
- Jon

check the fuses ,
could it be that one if those torpedo switches (brakes , clutch , etc ) has busted, blowing a fuse
or chafed wire somewhere ?

just a thing worth checking

good luck

Starter motor getting dirty inside can cause all sorts of gremlins.  That would be my first guess.

Charlie, I checked the fuses. They're all good.
Duck, good thought on a dirty starter as something to check out when I get home, but I think pulling the starter might be a bit ambitious for a hotel parking lot repair.
- Jon

Remove the lead from the relay to the starter at the relay and see if that makes the headlight come on. If that works as I suspect it will then remove the 2 pin plug onto the starter relay and reconnect the main lead and see if that makes the headlight come on as I suspect it will.
Try that and see how it goes.
I will be on line for quite a few hours yet so if you need any more help I will be here.

Rick,
No change. I tried disconnecting the lead to the starter (#87), tried disconnecting the 2-pin plug, and just for the heck of it, tried disconnecting #30 too. No headlight with any setting.
- Jon

I am pretty sure your ignition switch is whacked.   That is why the headlight and handle bar switch functions don't work while the engine runs perfectly.  Just last weekend I repaired the ignition switch on a K75 with those light problems.  A poor connection in the ignition switch on the lighting contact combined with a weak battery could produce what you are experiencing.  The ignition switch on these bikes is really a piece of crap.

You mention the starter running when the engine was running.  That is a symptom of welded contacts probably caused by starting with a weak battery.  The weak battery is also why after you replaced the relay you were hearing the start relay click when you pushed the start button.

It's also possible, but I suspect unlikely that you have bad grounds or funky battery connections.  Wouldn't hurt to check them.

You might also want to get the battery load tested.  I am pretty sure they will do a load test for you at any battery shop or some auto parts places like AutoZone.

Point-Seven-five wrote:I am pretty sure your ignition switch is whacked.   That is why the headlight and handle bar switch functions don't work while the engine runs perfectly.  Just last weekend I repaired the ignition switch on a K75 with those light problems.  A poor connection in the ignition switch on the lighting contact combined with a weak battery could produce what you are experiencing.  The ignition switch on these bikes is really a piece of crap.

You mention the starter running when the engine was running.  That is a symptom of welded contacts probably caused by starting with a weak battery.  The weak battery is also why after you replaced the relay you were hearing the start relay click when you pushed the start button.

It's also possible, but I suspect unlikely that you have bad grounds or funky battery connections.  Wouldn't hurt to check them.

Yep that is the likely culprit

Bikesmith wrote:Duck, good thought on a dirty starter as something to check out when I get home, but I think pulling the starter might be a bit ambitious for a hotel parking lot repair.

You needn't wait until home. Try #1 on this list. If that helps, clean the starter after cleaning the ignition switch and replacing the battery when you arrive home.

Rick and .75, I tried rebuilding the ignition switch. I concede it wasn't the best possible job doing it in a hotel room with no deoxit or even a pencil eraser, but I tried. No difference. Still no headlight.
The battery, though... That triggered a thought. Something I didn't mention in the original story is that it was a pretty cold day of riding. So I had the heated grips and my heated vest on most of the day. My battery is actually pretty old. I'm now wondering if that high load was the final straw. There's an Autozone right next door to my hotel. I think I'll take the battery over to check it in the morning.
Latch, I'll try that starter cleaning tip in the morning, too.
Thanks, guys!

It might make for a temporary fix but whacking the starter motor with a crescent wrench or something to knock the dirt around might help.

An 85 RS you can pull the starter in a parking lot no bother. No ABS or anything in the way, just get coils and battery out of the way and out she will come.

Definitively a starter problem.
When the starter is not energized, it provide ground to the electric system.
Having the starter running permanently for a while certainly chewed the brushes.

92KK 84WW Olaf wrote:An 85 RS you can pull the starter in a parking lot no bother. No ABS or anything in the way, just get coils and battery out of the way and out she will come.

You can get the starter motor out without messing with the coils.

duck wrote:

92KK 84WW Olaf wrote:An 85 RS you can pull the starter in a parking lot no bother. No ABS or anything in the way, just get coils and battery out of the way and out she will come.

You can get the starter motor out without messing with the coils.

You can.......just found it easier to unbolt them but not disconnect them.

Just remove the two bolts that hold the back of the starter down. Then rock it side to side while pulling.

Crazy Frog wrote:Definitively a starter problem.
When the starter is not energized, it provide ground to the electric system.
Having the starter running permanently for a while certainly chewed the brushes.

Just so that this doesn't become the truth because it was on the internet I would like to clarify something.  The starter does not provide ground for the electric system as stated above.  It only provides the ground for the load shed relay.

kioolt wrote:
Just so that this doesn't become the truth because it was on the internet I would like to clarify something.  The starter does not provide ground for the electric system as stated above.  It only provides the ground for the load shed relay.

This is correct and this is shown on my diagram (Not from the internet but from my EFI troubleshooting page). if the coil of the load shed relay is not activated or doesn't get enough power, lights, flashers, horn,.... will act weird or not work at all.
This is why when reading the symptoms of the problem, I pointed out the starter.

I also forget to mention something about bum starting a K100.
Even if the starter doesn't work, it's a very good idea to press the starter button when releasing the clutch.
Why and what's happening when you press the starter switch?

The starter relay and Fuel Injection relay close, Hall sensors get power.
The FI relay energizes (+) the fuel pump, the idle switch, the injectors and the air flow meter.
The Jetronic receives (pin #4) the signal that the engine is starting and it sets itself on starting mode (enriching the air/fuel mixture)
Electronic ignition module pin # 9-10-14 send power to the ignition coil
Electronic ignition module pin #8 send engine rpm info to pin #1 of FI computer
Electronic ignition module pin #7 send ground to the coil of the FI relay as soon as the starter switch is depressed. The ground will stay on after the starter switch is released as long as the Electronic ignition module receives a signal from the Hall sensors.
Notes:
Under 1300rpm, the timing is set to 6 ̊. Then, the Electronic ignition module will modify the timing according to the engine RPM.[/quote]

Hey everybody,
 I made it home! I came home the direct way instead of the meandering route that I took yesterday. About 300 miles. The bike ran perfectly except for lack of starter, lights, horn and signals.
  Starting the bike cold this morning in sub-freezing weather was challenging. Took me about 10 attempts, but I got it. After that it was a pretty uneventful ride. I stopped at gas stations that had a bit of a slope as you left, and the bike bump-started perfectly every time.
   I gave a lot of thought to what might be wrong and I kept coming back to the load shed relay. The problems were isolated to load-shed items and everything else worked perfectly. But I tried replacing the relay yesterday and it didn't help. Crazy Frog's suggestion about fried starter failing to provide ground to the relay makes perfect sense. It explains everything.
  So, is the starter completely shot or can it be repaired? Crazy Frog, you specifically said that the brushes were fried. I see they're available as a brush set (Not even expensive ). Is that likely to set things right or have I done other damage to the starter, too?
  Thanks again for your help, guys!
   -Jon

Most of the time, a starter could be fix.
The first thing to do is to dismantle it to assess the damages.
Caution: Mark the position of the front and back cover. If you reverse them, the starter will turn the wrong way.
What you will mostly find is that the brushes are gone and the copper track on the shaft may dirty or scored. It's easy to sand it to be smooth again.
Open the starter, take pictures and we will help you in your assessment.

Here's something that a lot of people get confused.  The load shed relay will not keep the starter from working.  The starter will keep the load shed relay from working.  

A very easy way to tell if the starter is keeping your load shed relay from working (no headlight is a symptom) is to just jump the starter terminal to ground with the key on.  DO NOT PUSH THE START BUTTON, BAD THINGS WILL HAPPEN IF YOU PUSH THE START BUTTON WITH THE JUMPER ON.  If the headlight comes on that means you have completed the missing ground path through your starter with your jumper wire and energized the load shed relay.

UPDATE!
   So, here's what's happened since I last updated you guys.
   I ordered a new brush set for the starter, rebuilt the starter, installed the new brush, cleaned all the contacts. Pretty easy job. I tested the starter by hooking it up to a battery and it works great.
   I installed it back in the bike. When I turned the key the electrical system mostly came right back to life. Horn works, turn signals work. No headlight, but I'm not too worried about that. It might just be a burned out bulb. If not, I'm sure it'll be pretty straightforward to fix.
   Here's the problem, though. When I pushed the starter button, the starter made a hell of a noise, kind of a loud HONK, like an angry goose.
   I figured somewhere in my misadventures I must have killed my starter clutch. I ordered a used one off eBay for $40 and set aside this weekend to install it. Holy moly, that thing is buried. Last night, after several hours of parts removal, I got the old starter clutch out and... it's perfect. Like it just came out of the factory. Working perfectly, flawless. I've never been so disappointed to have a perfect part. The countershaft is flawless. I didn't figure the problem was inside the engine, since the bike got me home running great. But just to be sure I manually rotated the engine a few turns to check if anything seemed amiss. Nope, dead smooth.  
  So I put everything back together, super clean, freshly greased. I took the opportunity to seal the intermediate housing to the engine a bit better.
  I got everything back together a few minutes ago, and it still makes the noise. HONK! The bike does start though. It seems like the starter is making the noise about 2/3 of the time, while having no effect. 1/3 of the time it makes the normal starter noise and the bikes starts instantly.
   So I'm baffled. I have no further ideas at this point. So, what do you guys think? Any ideas!
     -Jon

I would be inclined to check the starter motor out a bit more closely. Pull the armature out and check to see if any of the segments of the commutator are connected to the steel of the armature or shaft and also check that there is a connection between the opposite segments of the commutator but not to the other segments. Also check to see if any parts of the armature are rubbing on the magnets. That honking or growling can be a sign of a bad armature.

Can you post a video of the noise?  I'm having a hard time understanding what you are describing as a "honk".

Right now, I'm thinking that you have a loose bearing that is spinning, or possibly a loose magnet.  I had a starter that had a magnet get loose.  They appear to be glued into the case with something like epoxy, and the glue can let go.

If it is a bearing, you might try lubing the starter shaft where it goes through the bearings with a tiny bit of spline lube and see if that stops the noise.

Point-Seven-five wrote:Can you post a video of the noise?  I'm having a hard time understanding what you are describing as a "honk".

This might qualify as a honk but to me it's more like a bichon frise with laryngitis whining for a biscuit.
https://www.youtube.com/watch?v=k9SEV2YVLvc

Hi, everyone!
  I brought my starter into work today and just took it apart. Now that I'm looking for additional problems something jumps out at me immediately. Where the end of the armature fits into the collector guiding is a VERY sloppy fit. Almost a millimeter of play. That strikes me as problematic. I don't see any scoring on the magnets, so it isn't enough play to let the armature touch them, but the brush that I just installed does have a very small chip out of it, so I'm thinking that it's enough slop to allow the commutator to play rough with the brushes. I'm about to fire up my lathe and make a brass bushing for a tighter fit.
  I just wanted to check with collective opinion and see if there's anything I'm missing. Is that millimeter of play there for a reason? Is the bushing a bad idea for some reason?
   Thanks as always!
    -Jon

It sounds like you have a lot of wear in the end cap.  I wouldn't expect more than a couple thousandths of an inch of clearance in there.

I can't see any reason not to try making a new bearing.  You might want to take the old bearing/end cap with the armature to a bearing shop.  An oilite bushing shouldn't cost more than a couple bucks.  Before reassembly, I would put a light film of spline lube on the shaft.

Final Update! Fixed!
   The starter bushing did the trick. Here's what I made:


And here's how it fits in the end cap:


I made it a tight transition fit to the end cap (though I used a tiny bit of loctite 620 for good measure), and a free running clearance fit to the armature shaft (greased).
   I popped the thing in the bike the minute I got home and it's perfect. In fact, it's the best the bike has ever started. Despite the bike being at just a touch below freezing it started in probably a quarter second (several times!) You can barely even hear the starter. The bike is just instantly running. Yaaaayyy!
   Don't you love when you fix something and it's better than before you broke it?
   Long live the Flying Brick!
   Thanks for all your help, guys!
   -Jon


PS - I still have the headlight to fix, but I confirmed this evening that high beam is working so I'm pretty sure I just burned out my low beam. Not much else it could be, right? The new bulb arrived today (with M&Ms! Thanks, MaxBMW!) I'll install it soon.

Nice job!  It's great to have the tools to make parts like that bushing. 

I hope you used spline lube with moly.  The side loads on that bearing are pretty high and the moly will help a lot.  Now that I'm thinking about it, I just found a new job I have to do on my bikes this winter.

As for the headlight, the low beam doesn't last forever.  I've had two(or is it three) low beams burn out on my bikes.

A happy ending for sure!  Did you make the new bushing on the lathe in the background of your first picture?  It looks like a gem.

Woodie,
    Yep, That's my beast in the background. A 1912 Pratt and Whitney. A Christmas gift from my wife. I love it!

Now that's a Christmas gift!  I am slowly culling my herd of vintage machinery in order to make room and pay for all things K.  

I can't imagine a woman who would buy something like that for a gift.  You are a truly lucky man!!! 

Those old machines are so nice.  I have a drill press of similar vintage.  Damn thing weighs 300 pounds.

After 40 years in my shop it's going to be needing a new belt.  Do you know a source?

I've just finished rebuilding my 40 year old approx Vespa V twin compressor. I rang a local compressor specialist and was told I'd never get one as good if I bought a new one. Parts no longer available so I ended up hand lapping the four disc valves on a pane of glass it took about six hours. And due to one of the windings being stuffed I replaced the motor with a slightly larger one up from 1- 3/4 HP to a 2 HP. I just have to modify the belt guard but it is up and running pumping out 120 PSI instead of the previous 50 PSI. I also own a approx 60 year old Advance brand metal lathe made in Melbourne.
Regards Martin.

Leather belt .75?  You can get it on-line in the US and I could probably dig up a source in short order though local is also quite likely.  I happen to have a stash of joining clips out in my shop so all you will need is the leather.

Woodie wrote:Leather belt .75?  You can get it on-line in the US and I could probably dig up a source in short order though local is also quite likely.  I happen to have a stash of joining clips out in my shop so all you will need is the leather.

That's why this forum is so darn good.
Its got great spirit and I love it.

Woodie, that's good news.  I'll have to do a search.  The place I got the one I have now went out of business 30 years ago. 

The one I have now is scarfed and glued, and has to be shortened to compensate for the stretch.  Maybe if I can get the clips I can just shorten it.

I can supply you with enough to do again in 40 years and many 40's after that.  I still haven't enjoyed a beef on weck so I would be happy to meet up on your side of the border to deliver the goods.

Woodie, sounds good!  Maybe some time over the holidays?

Done!  I'll be off between Christmas and New Year's and would love to pop over.  How wide is your belt?