DDK - Die Deutschen Klassiker

Thought I'd run the engine up this morning - get everything warm make sure it was all OK.
Started fine but the charging light didn't go out even after running for a while, at about 4000rpm it dimmed but that was it. Put a volt meter on the battery with the engine running and it showed 12.5 volts. Voltage reg was replaced less than 1000 miles ago - so doubt that's the problem. Any ideas, do I need to pull the alternator?

Tony

Can you do a voltage check on the alternator B output cable (without removing the fan). On my car I can test the cable at several connectors including the feed to the cdi box. On mine it shows 14.5 Max at that tpoint but I lose a volt of that by the time it gets to the battery. Not sure if that is OK. However, yours seems low at 12.5 and I assume won't run for long as its not charging. Do you see a drop with all loads switched on?
Cheers
Will

Thanks Will, you've given me a couple of things to try

Tony

12.5v is a 1/2 charged battery. So no alternator output there.

Duh, missed out the important word 1st time.

No probs Tony. I am looking at same issues today on mine. Drop me a pm if you want to compare findings. Good luck. PS first job, check main ground strap is securely connected.