Alternator electrics on late single

Richard,

As far as i know it is only the stator that varies.

I have a Commando 12V 120W, with a modern solid state reg/rect,on my wideline ES2. The mounting studs seem to be a smaller diameter than on the Commando so a friend turned up some sleeves to go over the studs/through the stator totake out most of the slop - after i burned out a stator when it slipped and lost clearance without the sleeves despite care on mounting/tightening etc.

cheers

Iain.

It doesn't matter if the stator is a "6v" or "12v" one. The alternator can be used to charge a 6v or 12v battery. The 6v stators had 3 wires coming out of them, and switching was provided to only provide limited output when only the engine was running, and more output when the lights were on too. By using a double bullet connector, the stator can be made to charge at full rate at all times. A Zener diode controls charging for a 12 volt battery, just like it does for a 2 wire 12v stator. Back in the '60s the magazines were full of articles on how to convert from 6v to 12v.

You will obviously need a rectifier, Zener diode with heat sink, 12v coil and 12v bulbs to do the conversion.

Colin.

There are two rotor sizes, 70mm & 74mm. The RM15 & 18 alternators use the 70mm rotor, which are no longer available, the only option is to have them remagnetised, the RM 19 & 21, & all subsequent alternators, use a 74mm rotor, the small rotor will not work properly in the large stators &, obviously, you can't fit a 74 mm rotor in place of a 70mm. The differnce between the RM19 & 21 is the 19 is a three wire stator & the 21 is a two wire stator, you can turn a three wire into a two wire by simply joining the green/black wire to the green/yellow wire. All the three wire stators can be used on 6 or 12 volt systems, although the RM15 & 18 are only rated at about 80 amps wereas the RM19 & 21 are nearer 110 amps so if using the 15 or 18 on a bike with coil ignition & high wattage headlight etc, you may be left embarrased so best to upgrade to an RM19 or 21 but you will need both the stator & rotor.

The man to talk to is Al Oz at AO Services, he's the clubs electrical guru & can tell you exactly what you will need to do & what is the best way forward.

HTH, Regards, Tim

Previously richard_moss wrote:

I am trying to recommission a 1936 Model 18. Unfortunately, the oil pump was seized and damage has been caused to the drive gears. The engine is in a very worn state anyway and needs a complete rebuild.

I am fortunate to have a spare engine and I believe that this is from a very late ES2, maybe 1960's. I have removed the original engine and installed the ES2 engine already and have some information re. primary drive sprocket alignment differences, but it looks like that will be do-able.

I will need to set up for the different electrical system for this engine though, but initially need to know what the alternator output voltage is.

I seem to remember somewhere that the output was cahnged to 12V sometime in the sixties... Is that correct?

How can I tell this?

Many thanks

Previously john_oldridge wrote:

Hi Richard, this is my first post, so hope it works.

I have a 1960 model 50, and i have just converted to 12volt, with the help of Mick Hemmings. I bought a new RM 21 Stator and Rotor, and a Boyer Power box, which does away with any other electrical bits, ie diode and rectifier etc.The alterations to the existing loom were very simple, and so far so good, at last lights that can be left on for daylight running, my bike has coil ignition, so apart from 12v bulbs and a 12v coil everything stayed.

Regards John.O

Previously richard_moss wrote:

I am trying to recommission a 1936 Model 18. Unfortunately, the oil pump was seized and damage has been caused to the drive gears. The engine is in a very worn state anyway and needs a complete rebuild.

I am fortunate to have a spare engine and I believe that this is from a very late ES2, maybe 1960's. I have removed the original engine and installed the ES2 engine already and have some information re. primary drive sprocket alignment differences, but it looks like that will be do-able.

I will need to set up for the different electrical system for this engine though, but initially need to know what the alternator output voltage is.

I seem to remember somewhere that the output was cahnged to 12V sometime in the sixties... Is that correct?

How can I tell this?

Many thanks