Identify the Dynamo and Terminals

[Chris Launders]

They will often need more than a soft cloth, if it has been stood a while it might need a bit of 1000 paper while it's running.
Dynamos can be strange beasts, the one on my twin never needs touching whereas the one on my Brough needs the commutator doing every few hundred miles.

 

[oexing]

I am not very familiar with that type of dynamo but before you take it out of the engine you could just take off the sprocket or drive gear. Then, with negative earth battery , get a charger or better a charged battery , connect negative pole to dynamo or engine case. Then the positive wire onto connected D and F terminals on the dynamo. Now the dynamo should start spinning - in same direction as when engine running. When direction is wrong you swap field connections inside the dynamo. Or else you got positive earth on your bike and swap the battery poles. When nothing happens the dynamo is crap or internal fault somewhere.
Or am I quite wrong in my logic on the way ?

Vic

 

[timetraveller]

I've been keeping out of this as I am rather unsure of the facts but, from memory, the last time I saw a dynamo that looked like that it was either on my first bike, an ex-WD side valve Royal Enfield or my second bike a 1947? Triumph 3T. If I am correct then it is a very old model and possibly, even in good order, might only produce 40 watts. If someone out there knows better than me then fine, but I do wonder whether this is the correct dynamo to be used on a Vin.

 

[poor1]

Thanks for all the information.

If anyone has a working, or one suitable for reconditioning, Lucas dynamo for a Comet for sale please PM me

 

[Matty]

If it is a Lucas Dynamo the idea of flashing the field to battery positive is to set the magnetic field into the correct direction for positive out put. This is standard practice and should always work if all the rest of the system is OK.
Otherwise as suggested look on the BRITESPARK site for excellent advice.