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BMW R100RT 1990 -Start Problem

1.3K views 5 replies 3 participants last post by  DannoXYZ  
#1 ·
Hi folks, I have the above bike, which has a new alternator (600 watt Upgrade) and is charging ok, yesterday after stopping and starting 3 or 4 times, on the 5th occasion the bike would not start.

The Symptoms:
The 3 centre electrical lights on the dash dim to nothing when the starter button is pressed, and the volt meter drops to 0.
I then turn off and on again the lights and voltmeter are back on, if I continue to press the start button there is a buzzing noise from under the tank and the rev counter moves upwards. Stop pressing the button the rev counter falls and buzzing stops.

Tank was taken off and I identified the buzzing to the starter relay, which I assumed was faulty - so ordered and received a new starter relay, replaced old one and everything is exactly the same!

Anyone have any ideas what his could be?

Any help appreciated

Dave Mc
 
#2 ·
That sounds like a weak battery. Get the battery tested at an auto parts store. Or, if you have a voltmeter, you can do a rudimentary test yourself. Voltage at the battery terminals should not drop below 10V while you're pressing the starter button (with the key on, of course).
 
#3 ·
dead battery

test and measure to come up with numbers:
  • to verify that charging system is working properly
  • to verify you don't have parasitic drain when off
otherwise your new battery will die slow painful death just like current one.