Hello, I have a 1987 bmw K75S, it was running last week but after coming back from a ride down the road, it wouldn’t start up again, pressing the start button and it won’t make a noise. The battery is charged, kill switch of off, side stand is up, clutch is in, tranny is in neutral, the lights come on when the Ignition switch is on, the blinkers high beam and horn work as well. I tested the starter relay and it works, same with the fuel pump, it works. It doesn’t crank when the start button is pressed, BUT just a few days ago it worked fine.

Two Questions:

1.  How many miles?

2.  When was the last time you checked the brushes in the starter motor and cleaned the commutator?

Bonus Questions:

Is the ground wire to the side of the transmission tight? 

Are the connections on the starter motor tight?

Asher123 wrote: BUT just a few days ago it worked fine.

A close variation of that theme comes up in hospital ICUs and emergency rooms everywhere and often.  

Your K75S doesn't have a side stand switch so it doesn't matter if your moto's side stand is up or down. I'm interested in how you tested the starter relay and the fuel pump, and but mainly I wonder whether you've checked for power into and out of the starter button.

I guess the starter has good earth through its mounting bolts, but you could check for that.

I guess the starter is getting power. With the start button pressed, you should have 12volts at the starter terminal.

If the starter is getting earth and power, but it's not turning, it's the starter.

Asher123 wrote:Hello, I have a 1987 bmw K75S, it was running last week but after coming back from a ride down the road, it wouldn’t start up again, pressing the start button and it won’t make a noise. The battery is charged, kill switch of off, side stand is up, clutch is in, tranny is in neutral, the lights come on when the Ignition switch is on, the blinkers high beam and horn work as well. I tested the starter relay and it works, same with the fuel pump, it works. It doesn’t crank when the start button is pressed, BUT just a few days ago it worked fine.

Please read the forum rules before posting a question. This is the Member's Intro section. This thread should be in Troubleshooting.

Hi,

to this forum!


Bernie

Welcome… first try simple push to start button and be sure on/off kill switch is in the correct position. I know sounds… but

Oops! I’m bad, just re read original post.