I was having a lovely drive around my locality in the UK when my ‘50 Rocket 88 made a serious screeching noise for a second or two - then it disappeared. Half a mile later it happened again and this time didn’t stop. Pulled over, turned the engine off and checked the drive belts. The dynamo one was hot but so was everything else. Started her up an and screeching continued which was getting peoples attention. Knowing I had a spare at home I decided to cut the dynamo belt drive - the engine bay was too hot to start stripping things down and it was starting to get dark. The dynamo pulley was locked solid and I thought it would be the main bearing. The noise had disappeared and I drove the 7 or 8 miles home (with full lights) just on
the battery. Below is what I found on stripping the dynamo down.


God alone (and perhaps some clever people on here) knows what could cause this - the armature windings and commutator look fine. It will cost more to have it rewound than to buy a replacement from Fusicks. My question is that I have heard that in the event of a serious failure of the dynamo you should also change the Voltage Regulator. Does any body know, or have experience with this? Many thanks in advance for any advice.

 

Yes, I would replace the voltage regulator. That is catastrophic failure of your generator.