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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Doodaadog on June 22, 2018, 09:59:25 AM

Title: Low voltage from start button
Post by: Doodaadog on June 22, 2018, 09:59:25 AM

Helppp....hello fellow Bricksters.....almost at the end of my recommissioning of a 92 K1100 LT...
It had been stood for 9 years...yup 9 years.
Have managed to get it running and MOT’d after many a trial and tribulation.

But....it has developed a fault at the start button....I’m only getting 6v (ish) through.....managed to bypass it and rigged up a temporary start button....which throws 12v (fused) direct from battery........but would love to fix it.

Things I’ve tried...
Dismantled handle bar switch, cleaned contacts, checked spring etc. I do get a continuity when I put my meter across the terminals....when I check Volts I am only getting 6v.....?

Checked for loose or corroded terminals / connectors

Checked for chafing / mouse nibbles etc.....

All test OK

Any help appreciated

Regards Greg

Title: Re: Low voltage from start button
Post by: The Mighty Gryphon on June 22, 2018, 10:51:20 AM

You have cleaned the pushbutton contacts inside the switch with Deoxit, haven't you? 

Are you getting 12v to the start button contacts?

Title: Re: Low voltage from start button
Post by: Doodaadog on June 22, 2018, 02:55:13 PM

Haven’t tried deoxit not seen it here in UK, have ‘scratched’ contacts, I’m hoping that it will be as easy as the contacts....
Thanks for taking time to reply...
Regards Greg

Title: Re: Low voltage from start button
Post by: Laitch on June 22, 2018, 03:09:38 PM

Quote from: Doodaadog on June 22, 2018, 02:55:13 PM

Haven’t tried deoxit not seen it here in UK . . .

It's there somewhere (https://www.google.com/search?q=deoxIT+uk&ie=utf-8&oe=utf-8), apparently. Your ignition switch might need cleaning also. Instructions are on the site. Check the incoming voltage to the switch as Gryph has indicated.

Title: Re: Low voltage from start button
Post by: Martin on June 22, 2018, 03:33:07 PM

Try Jaycar UK for the DeoxIT. It now comes as a two part spray first one cleans, the second one gives it a coating to aid conductivity.
Regards Martin.

Title: Re: Low voltage from start button
Post by: Inge K. on June 22, 2018, 04:00:26 PM

Check the voltage at the black/green wire on the multi connector for the RHS switch assy which you find
under the fuel tank.
Measure on both sides of the multi connector while pressing the start knob, and then pull the clutch and
see if that makes any difference.

Title: Re: Low voltage from start button
Post by: stokester on June 22, 2018, 07:03:46 PM

Quote from: Inge K. on June 22, 2018, 04:00:26 PM

Check the voltage at the black/green wire on the multi connector for the RHS switch assy which you find
under the fuel tank.
Measure on both sides of the multi connector while pressing the start knob, and then pull the clutch and
see if that makes any difference.

As Inge mentions, check for voltage under load. 

A meter will show the proper voltage with corrosion on terminals and with all but one strand broken until put under a load.

Title: Re: Low voltage from start button
Post by: Doodaadog on June 24, 2018, 05:04:21 AM

Thank you for your ideas...will try them out and report back

Title: Re: Low voltage from start button
Post by: DEcosse on June 26, 2018, 01:50:15 AM

Quote from: Inge K. on June 22, 2018, 04:00:26 PM

....  pull the clutch and
see if that makes any difference.

This part is a key component in identifying where the fault lies:
The 'start enable' (which is the INPUT to the Start Switch) has two possible sources;
EITHER the Transmission is in Neutral OR you have the clutch pulled.

So ....
Pulling clutch makes no difference - problem would be in the start switch itself, oxidation/pitting of the contacts
Pulling Clutch DOES make a difference - problem would be in the Lunch Box