So when I turn the key to the on position, with the kill switch in the run position, the bike sometimes will start when I pull the clutch lever in--before I push the touch start button.

If the bike is in neutral, and I do the starting process--the bike sometimes cranks a for a sec then the speedo goes blank or a second as it's lost power. (Almost like a loose battery terminal or failing connection.

Electrical gurus--what should I be testing? Battery is 13.5v and drops to 13.2v on start up so that seems to be okay

When I had very similar issues the fix for mine was cleaning the carbon deposit that accumulated on my starter motor. Pull it out and apart and use a pencil eraser to remove the carbon. I don't have a part number for a $199.00 BMW OEM pencil but any should work. I have done this in a parking lot of a Circle K at 2AM in the middle of Texas.

It's been several years since I've cleaned in contacts in the starter. Definitely worth going through. I wonder if I can source some used BMW pencils 🤪

This form inspired me to start using all different types of parts on my bike. From building Fuel Pumps to putting sport bike front end on it with a Cognito moto axle and triple tree.

I have the pencil and the really rare matching pencil sharpener.
Regards Martin.

Check the starter button the small spring may have collapsed causing the button to always be in contact.

What bike you got, what year, how (electrically) stock is it? 6, 8 or 16 valve?

How do you normally start it, like do you always pull in the clutch before pressing the start button? For example I don't use the clutch, the kill switch is always engaged, never use the choke, I just turn the key on and press the start button while it's on the centre stand.

Are you doing anything different to usual when you have this problem? Does it only happen say when warm, or on the side stand, or with the handle bar turned left, turned right etc?

With the key on, does it crank with the handle bar turned left or right, or with the instrument cluster wires wiggled, right handlebar wires wiggled, or other wire's wiggled, or the kill switch wiggled?

When you press the start button you should feel the spring compress, when you release the button you should feel the spring pushing the button back up again.

I'll definitely check the spring under the button, Duck. Though it feels like it's in place. The outer edges of the green button fell off years ago, the only difference I've noticed is, it's harder to start with gloves until this problem.

Generally, I have the bike in neutral turn the key hit the button and it fires on. Rarely do I pull the clutch--just noticed that malfunction upon troubleshooting.

I'm going to clean the starter brushes and check the spring underneath the push button start as advised. 🫡

It's the outer part of the green button that retains the spring, so I guess the spring has been missing for years too.  So let's say the start button is engaged on the occasions when it starts before you press the button when you pull in the clutch, but then it should have started before you pulled in the clutch. That makes me guess your new problem is that the gear indicator switch isn't working properly. In that case the neutral light wouldn't be glowing while you have this problem. If it does glow while you have this problem before you pull in the clutch, which then results in the starter turning, then my guess is wrong.

This guy in Spain sells replacement start buttons:
http://www.hardtoptire.com/producto_en-hardtop.php?id=177&id_familia=105&id_catalogo=19

Not happy with my grammar last time, this is what I was trying to say.


Also the gear indicator should read 0 while the neutral light is on.

At the top of the drawing you see fuse one. I think you're saying that it's an intermittent problem when the instrument cluster lights cut out (Speedo lights) so check that fuse one is clean and tight, and replace the fuse with a new one. The fuses are deliberately the weakest link, might as well replace them all with new one's, they're cheap and easy to do. It's a good bit of preventive maintenance.

Thank you for sending the button replacement link--unfortunately I'm in California and I don't believe there's an option on his website to send here. I still have the underneath side of the button and will include a picture (the spring is still under there.)

I cleaned the starter brushes, and that seems to have resolved the issue. 


If anyone knows of a green starter button replacement in the US--I'd love to know about it. I have thought about making one and gluing it to the green part that exists.

Ok, with a multimeter, some questions about the starter relay.
With ignition off, do you have power at 86 black/yellow wire? You shouldn't.
With ignition on, do you have power at 86? You shouldn't.
With ignition off, do you have earth at 85 brown/red? You shouldn't.
With ignition on,  do you have earth at 85? You shouldn't

( Edit: that's if the problem returns)

Maybe revisit the questions about turning the handlebar, I don't like the way it looks like the switches make contact with the tank ( Edit: it looks to be non original forks which might be causing trouble with the wiring)

MikeisonTV wrote:If anyone knows of a green starter button replacement in the US--I'd love to know about it. I have thought about making one and gluing it to the green part that exists.

If you're still looking for alternatives, read all the way through this thread.