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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: aradileepan on October 04, 2022, 03:32:32 PM
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Hi, I think I'm having a starter problem
In January, I replaced my fan. Since then, I wasn't able to really ride until September.
In September, even with a strong battery, I get weak starter action and weird electrical issues (no headlight, ABS light blinking, flashers lighting together). I thought maybe the coolant temperature sensor was bad, so I'm about to replace it.
But should I also just pull the starter now? I think I just might.
I'll report back.
Best,
Ara D.
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The starters get a carbon build up which causes all sorts of weird electrical side effects. You can sometimes get a reprieve from pulling them apart using the roll back method. Roll the bike backwards down a hill with it in 4th /5th gear and pop the clutch a few times. This temporarily will fix the problem. However the better method is to remove the starter and pull it apart and clean up the commutator and brushes. Also check the brush length while you're in there. It is important to mark the stater casing before disassembly so it is assembled correctly.
Regards Martin.
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What he said. The electrical gremlins you describe are typical symptoms of a dirty starter. How many miles on the K? What year?
It's a PITA to take the starter apart so another option is to swap in a lower mile unit from Ebay or wherever. Here's one with only 12K on it for $24.79 with free shipping.
Just me but I'd do that before bothering with a rebuild.
https://www.ebay.com/itm/131268209104
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When was the last time you cleaned the connections in your electrical system? Dirty connectors and switches cause a lot of problems. There are a lot of connections under the tank, especially grounds that are attached to the frame that can cause a lot of strange problems when they are loose or dirty.
It's a good idea to get a can of Deoxit D5 spray and clean up all the connectors and wiring under the tank. I do it with every "new" bike that comes into my garage after I give that pile of wire a good cleaning with S100 Motorcycle cleaner. It will get get things under the tank looking and working like a new bike.
You also want to take a few minutes to clean the battery terminals and the main ground connection which is located on the side of the transmission below the ignition coils. I use the small brass wire brushes from Harbor Freight to shine up the ground lugs and give them a very light wipe of battery terminal grease you can get at the auto parts store.
While your problems may be related to the starter, a bad relay, or switch somewhere, cleaning the connections will help immensely in troubleshooting and should be the first step in getting the electrical system on these old war horses working properly.
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When was the last time you cleaned the connections in your electrical system? Dirty connectors and switches cause a lot of problems. There are a lot of connections under the tank, especially grounds that are attached to the frame that can cause a lot of strange problems when they are loose or dirty.
It's a good idea to get a can of Deoxit D5 spray and clean up all the connectors and wiring under the tank. I do it with every "new" bike that comes into my garage after I give that pile of wire a good cleaning with S100 Motorcycle cleaner. It will get get things under the tank looking and working like a new bike.
You also want to take a few minutes to clean the battery terminals and the main ground connection which is located on the side of the transmission below the ignition coils. I use the small brass wire brushes from Harbor Freight to shine up the ground lugs and give them a very light wipe of battery terminal grease you can get at the auto parts store.
While your problems may be related to the starter, a bad relay, or switch somewhere, cleaning the connections will help immensely in troubleshooting and should be the first step in getting the electrical system on these old war horses working properly.
I think this is bad advice. I've never put any Deoxit on any Kbike connector and never had a problem. To me being that anal retentive is like HD riders polishing every bug off at every gas station.
I would rather ride than wrench.
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Weak starter action, I'm assuming that means the starter is cranking slowly but the bike won't start. It's normal that the headlight cuts out while cranking, but it should come on when the start button is released (with the ignition on)
Yep could be the starter motor, but might also be a weak supply of power, or earth, to the starter motor. Test to see which is the problem.
Run a jumper lead from battery positive to the terminal on the starter, then another lead from battery negative to the starter motor case. This bypasses the bikes wiring. If it now cranks normally, your starter is good. If not, it's a starter problem.
If cranking well in the above test, the problem might be a poor earth supply. Run a jumper lead from battery earth to the starter motor case. If it now cranks well, it's an earth problem.
If no different, check for a weak power supply. Since it's cranking that means the signal circuit is good, including the switches and plugs. So then check power from battery positive to terminal 30 of the starter relay, and 87 of the relay to the starter terminal. Then also check the starter relay itself, and it's connections.
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It's a good idea to get a can of Deoxit D5 spray and clean up all the connectors and wiring under the tank.
I think this is bad advice.
I think that to encourage somebody to think Gryph's advice is bad is bad advice in itself but we're free to express what we think here when we think it or even after we think it, at least that's what I think we think. So think that over, if you think you should. :laughing4-giggles:
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"I would rather ride than wrench."
The Duck has quacked...
Forget about fixing your electrical problems, bump start it and forget about working lights, just get on it and ride. icon_cheers
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I think this is bad advice. I've never put any Deoxit on any Kbike connector and never had a problem. To me being that anal retentive is like HD riders polishing every bug off at every gas station.
I would rather ride than wrench.
The only Harley I ever rode, I was looking for gas stations to stop and polish the bugs off, I was getting shaken up and needed a break from the vibration, noise, and ladies flashing me as I rode by. Mostly I needed a break from the first two things.
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I was getting shaken up and needed a break from the . . . flashing me as I rode by.
I heartily recommend Thera Tears eye drops. Although they don't eliminate the flashing, they do keep your vision clear while it is happening. :laughing4-giggles:
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I didn't answer the weird electrical part of the question.
The first thing the headlight and indicators have in common is the Load Shed Relay. A quick test, turn the key on, you should hear a faint click from the relay box, that's the LSR, and the lights should come on. Sounds like this isn't happening, often that would be due to worn starter brushes.
The flasher unit gets switched power from fuse 7 (through the LSR) and constant power at pin 30 so that the hazard switch can operate all four indicators without the key. So with a turn signal switch providing earth to complete the circuit, and without power from fuse 7, it may get power from the hazard circuit and they all flash. Removing fuse 7 will probably reproduce your flasher symptoms after you fix the problem (Edit: no that's not it, just tried it, I have done it in the past but don't remember how)
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Sorry for the delayed response. This is some great stuff.
I'm waiting on a reman'd starter from Euro Motor Electric. I got a starter rebuild kit from them and botched up the brush replacement. The old brushes were worn way down.
I'll button it all back together hopefully this weekend and get on the road.
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Starter is in, but the thermostat gasket crumbled, so I'm waiting for that to come in. A quick bump of the button and the starter sounded way better. The brushes on the old one were way worn out.
Quick aside: the fuel line from the fuel rail: does it matter which port on the tank it attaches to (fore or aft)?
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the fuel line from the fuel rail: does it matter which port on the tank it attaches to (fore or aft)?
It only matters if the ultimate goal is engine performance as originally intended by the manufacturer. :laughing4-giggles:
(https://www.motobrick.com/gallery/4/1601-161022233303.png)
More impersonal guidance like this image and caption is available from the BMW K100/K75 2V Service Manual downloadable from the Service Manual section of this site's Technical Directory.
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Eek. Sorry. Thanks for the info.