Battery warning light

[Captain Black]

Went out on my R100R Classic today

All was going top banana until i pulled back onto the drive at home and noticed the battery light was on.
Now what seem's strange is that at idle it's barely on, but as i rev the bike the light goes brighter the higher the rev's and dim's when the rev's drop.
The battery is new and alway's hooked up to my optimate when not in use, and the battery terminals are all tight. Strange thing is i found what looks like a 12/13mm nut near the bike in the garage, now that may or may not be anything to do with it.
Any thought's please ?

 

[Rob Farmer]

Check the rotor out - Second page - A & B Just make sure you put a piece of paper under the brushes to keep them clear of the slip rings when you measure the rotor.

 

[cookie]

sounds like the diode board is the most likely suspect to me.

if the rotor was o/c then the lamp would never come on.

 

[Rob Farmer]

if the rotor was o/c then the lamp would never come on.

But if it was shorted out somewhere in the windings it wouldn't go off

 

[Captain Black]

Thank's Rob/Cookie

I'm going to take the front cover off and have a peek underneath over the weekend. Seem's odd that i found that nut near the bike though as i know the garage floor does'nt have any old nut's and bolts on it. Maybe it holds a wire on and has fallen through the bottom of the case ?? Long shot but worth a look. I'm going to the classic bike show at stafford this weekend so i'll try and get a look on Sunday sometime.

Seems odd it dim's at low RPM and goes brighter with higher rev's....

Would'nt be anything to do with the rectifier ?

 

[Rob Farmer]

The only thing under any of those covers with that size nut is the starter motor power lead nut. I think you'd know if that had fallen off.

 

[Captain Black]

Well checked the battery cold pre start and 12.7 Volts, when i put the meter on the plus/neg terminals at 3000 RPM i'm getting 14.3 volts. Would that suggest that the alternator/reg/rec are all doing what they should and maybe the fault is someplace else ?
The battery light does glow brighter the higher the rpm though.....
any thought's ?

 

[Rob Farmer]

Section 4.10

 

[Captain Black]

I'll give that a go Rob...Thanks..

 

[Captain Black]

At the risk of sounding like a numpty...why can't i get the plug out of the regulator ? I can see a piece of plastic with a groove in it under the plug on the Reg, but what's the secret to unclipping the plug ??

I don't want to break it

 

[Captain Black]

Got the plug out

Did the wire test across the blue and black plug wires, but still got the battery light on when i rev the engine, but not at tick over...well the odd flicker

Getting up and down volts at the battery on my meter, but no higher than about 13.5v at 3/4000 rpm ?

So i guess my reg is ok ?

Strange when it's all wired up i get a steady 14.1 ish volts at the battery so it's charging ok from the Alternator through to the reg/battery or am i missing something ? Faulty bulb or to simple ?