99 not charging

Hi Robert,

Rotor magnetismis everything, even if it looks 'sound.' I would suggest you replace the pair, minimum 180 W, with a solid state rectifier / regulator.

Your pocket, your choice but rotor stator clearance should be 0.008" no tight spots.

Good luck!

Rgds Steve

I think you will find that the rotor diameter has changed so that you will have to buy a complete alternator. Not that expensive anyway. Should set you up for the next 58 years. Get a 2 wire one, 120 watts is enough in my experience, with, as Steve says, a solid state voltage regulator.

royal Enfieldalternators are the same as rm 15 with emergence coil as well as ignitionand lighting coils the shaft size should be aroundthe same hope this may help anyone yours anna j

My spare 70mm rotor sits on the bench with a collection of small nuts and bolts clinging to it. Have had no trouble fitting a new alternator, though that was quite some time ago.

i wonder at what point a load on a charging circuit is seen as a short circuit .would the regulator just shut down not charging the battery

Previously robert_tuck wrote:

Thought provoking question Barry. We should always try to find the cause of a failure,I suspect insulation breakdown due to age . Previously I had run with a heavier load than normal (heated jacket!) that must have called for the max output and more.Did it die of old age or did I kill it?.Perhaps I should consider a 140 watt replacement as a minimum.Looking at replacements there appears to be Lucas (made by Lucas) and Lucas made by others pretending to be Lucas. I can feel the phobia kicking in!.

hello robert I woundered why my knees are bad it must be the insulation breaking down due to old age then have fun yours anna j

I would suggest asking the likes of RGM and Norvil about stepped studs for mounting alternator stators. I am sure that both provide these studs with their belt drive conversion kits for Dominators. Making a set has also got be a DIY possibility.

In the past I have cut small lengths off car and radio aerials to pack out the stator holes for a better fit. Rolled slices from Aluminium tins are just as good.

Attached photo shows exactly what you are looking for. At the bottom you can see this kit contains a set of stepped Stator mounting studs. Somebody must have supplied these to RGM, who then sold them on to me.

Previously robert_tuck wrote:

I have the new alternator (wassel) rm23 ,this is a high power single phase thats fitted to ES commando's . Not sure its a good fit on a dommy. The stator has more clearance on the studs and in the housing . Does it need thicker studs,sleeves or packing round the steel core? ,the wires appear to need to exit on the outer face ,the RM15 exited on the inner face,is this important?.

No. Weather the wires pass from the front or the back is not essential in any way. What is essential is that the wires do NOT foul or are fouled by the chain (s)

Be very wary of packing out studs with tin or aluminium plate. Some decently made studs with correct sizes and threads is what you need. ANY competent person with a lathe should be able to do this.

It is not just the cost of a failed alternator you are looking at but maybe a seized engine if this lot rubs and locks up at speed!

A great suggestion Barry but very expensive at £25 a set of 3.

Robert......those studs in the photo were used to mount the stator as part of the belt drive conversion for my 650 Dominator. They were exactly the right length to help avoid the output cable rubbing on the outer cover. More info can be found in this months Roadholder.

i had a newish battery with a bad connection. i found out it was a break in the battery terminal inside the battery. it only showed itself under heavy loads. the terminal wasnt loose. it was a case of one minute you had power the next you didn't or something inbetween.

Barry

Robert.....just remember to get the polarity correct. You don't want the compressor sucking by mistake. Otherwise the other campers might begin to wonder what is going on inside your tent.

I gave up on flattening my Commando battery after once falling asleep (unconscious) with the wandering lead light still on. Instead I now take a small garden solar light when I go camping. This sits by the entrance of my tent and helps me locate my way back after the bar closes.

My RGM belt Drive Conversion has now done 1000 miles. I checked it at 500 miles and again this week before heading for the Begonia. The extended and stepped Stator mounting studs, supplied with the kit, are excellent and have kept the 40 year old Lucas RM21 in place with exactly the right amount of rotor clearance. As can be seen in the attachment, the belt is a little tight due to the rear wheel pulling it backwards.

Robert.........buy a new 961 if you want to enjoy the pleasure/pain of battery drain. My Mk 2 Sport would flatten its battery after just 5 days of non-use. Owners that have an active alarm fitted find the bike has to be connected to a trickle charger every night. Other wise they will be trying to bump-start the beast the next day. I met two separate owners who used their bikes for touring around the UK. They both stayed overnight at hotels, set their alarms at night and then came out, the next morning, to discover non-staring machines. Once I measured the current drain by the sensors on my 961 and the meter showed 200mA per hour. That was with the ignition turned completely off and key removed.

Most battery overnight drain issues are generally down to one or two reasons. A failing battery cell. Places like Halfords can do a battery check for this. The other likely cause is a failed elctrical/electronic item on your bike. The favourites here are Zener Diodes, rectifier and shorting switches.

Robert ......way back in 1976, I did an electronics HND course and quickly learned about the advantages of replacing the old Lucas rectifier with a purpose built 4 diode job plus Zener. I instantly got brighter lights and battery that did not need charging so often. The Achiles Heal, at the time, was the expensive Zener Diode which appeared to have a life of only 20,000 miles until I fitted two of them.

With the advent of the 'all-in-one' rectifier / regulator you get an easy to mount and wire box (such as the A1) costing just half the combined amount for a Zener and rectifier. The one on my 650 is now 10 years old and I have had no problems. The one fitted to my Commando, coped with a 180W alternator and was still working fine after 25,000 miles.

Observations with regards to Zener diodes- I have not known of them leaking the power away when standing but maybe. They were last made in the 80s when Lucas last existed. Any thing purporting to be a zener since then is not of much use, some have a number like BCY on them, (too low power rating) another one is chinese and even google doesn't recognise it!!

The original Lucas zener was rated at 100W, this is fine when fitted to an RM21 120W as there is a small power loss across the rectifier, the battery takes some 20W the ignition takes some 20W so your zener has to cope with only 80W! but that is at 7000 revs so you are quite safe. Unless you revert to magneto ignition and inadvertently lose the battery then you are in for trouble as the 120W gives the zener too much stick.

There is nothing wrong with the rectifier Zener system, but the reg/rect might give you a more controlled voltage.