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k75rt starter does not engage

M

mark from maine

New member
I have a 91 K75RT with 80K. It would not turn over when I pressed the starter button so I charged the battery and it still will not turn over. Lights, horn, funtion fine. Bike started and ran great a week ago. Kill switch on right handlebar is in correct position, (up). Any suggestions will be much appreciated. P.S. Kick stand is up and tranny is in neutral. Key is turned to on position.

Thanks,
Mark
 
To be clear -

The starter spins but will not engage? Or it engages, turns the engine over and it won't catch?
 
When I push on the starter button, nothing happens. Starter does not spin. Starter does not turn engine over. It is if the starter has been disconnected or removed, but it has not. No work has been done to the bike recently.

Mark
 
42016,
sounds like a switch is not working. Have you tried moving the side stand a couple of times to see if that switch is possibly stuck? Possibly do the same with the kill switch. On my 85 when the kill switch is off I do not have any dash lights so this is a quick reminder to turn that switch on.

hopefully more knowledgeable gurus will chime in.

Roy
 
roy said:
42016,
sounds like a switch is not working. Have you tried moving the side stand a couple of times to see if that switch is possibly stuck? Possibly do the same with the kill switch. On my 85 when the kill switch is off I do not have any dash lights so this is a quick reminder to turn that switch on.

hopefully more knowledgeable gurus will chime in.

Roy
Click to expand...

Sidestand does NOT interact with the start circuit.
Switch (ignition and kill), relay, Starter or ground; all could be the problem. Is the fuel pump running when you hit the start button?
 
I do not hear the fuel pump running nor do I hear the starter relay click from under the seat area.

I should mention that the bike has only been ridden once every couple of weeks this riding season.(busy building a home and garage) 800 miles since spring. On occasion the engine has stalled out as I was slowing to a stop. It restarted with no problem but maybe needing to turn over a few times before running again. This has happened perhaps 4 or 5 times this season. Twice in one short ride, 25 miles. This was a few weeks ago.

I just tried the starter button and the only thing that seems to happen is the instrument lights dim a bit as the starter button is depressed.
 
I lifted the fuel tank and removed the accesss cover to the relay compartment and listened with my better ear as I pressed the starter button. I do hear a single slight "clicK" each time I press the starter button coming from the starter relay. I then replaced the starter relay with a spare that I have. Nothing changed.

Used a piece of sandpaper and cleaned up the battery ground wire before reconnecting to the tranny. Nothing changed.

Listened carefully for the fuel pump as I pressed the starter button but can only hear the starter relay as mentioned above. I do not hear the fuel pump whirrrr. Is it possible the fuel pump is not running because I have pushed the starter button so many times and fuel is already supplied?

Any suggestions what to check next?

Thanks,
Mark from Maine
 
The fuel pump only runs when the engine is turning over, even if only by the starter. I would check for voltage at the starter terminal ( on the starter ) when the starter button is pressed. If you see 12 volts, the problem is definitely the starter itslef. A '91 K75 might well need new starter brushes. If you get no voltage, work backward up the circuit diagram.
 
Cleaning

Your problem sounds like the one I had at the Fredericksburg TX Rally. The cause is a build up of carbon from the brushes on the commutator of the starter. When I pressed the starter button nothing happened.:banghead I was alone in a paved parking lot and tried to bump start my K75. That didn't work except that I pressed the starter button and it worked as planned. The problem was intermittant. The nice man who runs Motorad Electrik wouldn't sell me a new relay. He told me to take the starter apart and clean the carbon off with fine sandpaper. I got home by bump staring twice.
The brushes were fine. They are made of soft graphite so they don't wear off the copper commutator. The Clymer manual says to make a mark on the starter case so you put it back together the same way you took it apart. I didn't do that and got it wrong. The starter ran backward. I got do the job again - correctly. That was 10 years ago, so I am possibly due for another cleaning.
 
breyfogle said:
The fuel pump only runs when the engine is turning over, even if only by the starter. I would check for voltage at the starter terminal ( on the starter ) when the starter button is pressed. If you see 12 volts, the problem is definitely the starter itslef. A '91 K75 might well need new starter brushes. If you get no voltage, work backward up the circuit diagram.
Click to expand...

But the headlight lights up, so the shed relay is getting a ground thru the starter winding and brushes.
 
42016 said:
I have a 91 K75RT with 80K. It would not turn over when I pressed the starter button so I charged the battery and it still will not turn over. Lights, horn, funtion fine. Bike started and ran great a week ago. Kill switch on right handlebar is in correct position, (up). Any suggestions will be much appreciated. P.S. Kick stand is up and tranny is in neutral. Key is turned to on position.

Thanks,
Mark
Click to expand...

Have you disconnected "the brain" recently that sits on top of the battery?

If you've accidentally bumped the connection loose on this, you can't even get a crank. Unplug the brain, plug it back in, and try pushing the starter...
 
motoedde said:
Have you disconnected "the brain" recently that sits on top of the battery?

If you've accidentally bumped the connection loose on this, you can't even get a crank. Unplug the brain, plug it back in, and try pushing the starter...
Click to expand...

I always leave "the brain" connected to its wire harness plug when servicing the battery but I will double check the connection.

Thanks,
Mark
 
Thanks everyone for your time and experience. It means alot. I will try cleaning up the starter when I get just a little time. I may be a while getting back to you. I have a busy work week ahead. Will keep you posted on the progress.

Mark from Maine
 
Observations on the brain-

Make certain that you have the wire bundle that attaches to the on board computer zip tied and attached firmly to the frame. This bundle, if left to bounce around, will cause intermittent failures, including sudden death, refusal to restart and so forth.
 
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