MOTOBRICK.COM

TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: boostd4 on July 06, 2017, 02:56:41 PM

Title: School me on Alternator load light please
Post by: boostd4 on July 06, 2017, 02:56:41 PM

Hi,


I have a 1985 K100RS that someone started making a cafe racer project out of.  I swear through all my reading/searching about these bikes I read somewhere on this forum that the bulb in the instrument cluster was required for the alternator to work properly and that removing the cluster could ruin the alternator.


I bought the bike with no cluster.  It runs normally, I've maybe put 150 miles on the bike since I've had it and it has a stable idle and no symptoms I can discern.


Is there a wire I should have a resistor on?  Am I truly at risk for some kind of electrical failure without the cluster in?  I do plan on getting a KOSO cluster with basic warning light functions (temp/oil/neutral/battery,etc)

Title: Re: School me on Alternator load light please
Post by: Laitch on July 06, 2017, 04:35:25 PM

Quote from: boostd4 on July 06, 2017, 02:56:41 PM

I swear through all my reading/searching about these bikes I read somewhere . . .

Read these two threads. The first gives you information about the interaction of the cluster light and charging operation. The second gives you an idea of the correct output of a working alternator. You can use a multimeter for the test.
http://www.k100-forum.com/t8912-battery-charging-light-absolutely-necessary#104855
http://www.k100-forum.com/t6817-testing-alternator-output

Title: Re: School me on Alternator load light please
Post by: boostd4 on July 06, 2017, 05:30:45 PM

Thanks!  Very informative threads.  I joined that forum just yesterday (new to K-bikes).  It seems the concensus is that outside of a working bulb in the instrument cluster, the alternator can be triggered to charge by RPM as well.  Something like 2500rpm and the alternator circuit starts charging (vs immediately or 1000rpm with the bulb there?).

I don't idle my bike ever, really.... I'm riding within 30 seconds and 2500 rpm comes shortly after that.  I can test the alternator if I need to but don't have any symptoms.  Any other risks?

Title: Re: School me on Alternator load light please
Post by: Laitch on July 07, 2017, 07:26:28 AM

Quote from: boostd4 on July 06, 2017, 05:30:45 PM

I don't idle my bike ever, really.... I'm riding within 30 seconds and 2500 rpm comes shortly after that.

You must be on one of those bikes that spins donuts at traffic lights. :giggles