25DC lighting

[Mike Norris]

Hello all.
I have restored a 1961 25DC.
The engine and gearbox were rebuilt by Louis at Villiers . Most of the internals of the gearbox had to be replaced because it had been filled with water instead of oil.The engine had 1 h.c. head and 1 l.c. When fitted into the frame and everything bolted up it fired FIRST kick. I can strongly recommend the work. He also rang me when something extra was required, ectremel helpful.
The bike runs well but There is a problem with the lighting. 6 gloworms to the rear light and 10 to the headlight.
The brake light is fine.
I have checked all the earth points with a multimeter and all are very good. the output from the generator reads between 6.5 and 7 volts on a little throttle but the lights do not increase in brightness when the revs are increased.
The bike has been completely revired as per the villiers wiring diagram All wiring supplied by A.Osborn who amended the colours shown on the diagram to the modern equivalent colours. An extremely helpful chap.
Any suggestions please.
Thanks
Mike

[John Wakefield]

25DC Lighting

Mike
Not sure what you mean by 'glow worms' (volts, amps or watts?)
The fact you are getting 6.5 to 7 volts from generator suggests that all is ok with that. Where did you check the voltage? at the multi pin plug on engine or somewhere else in wiring. I assume that this is AC voltage.
Looks like the problem is with the rectifier, has this been replaced with a new one as the old selenium one will probably be u/s? Have you checked that the battery is receiving a charge without lights on? If so rectifier is OK, & the problem lies with the wiring or switch connections. There are two lighting coils in the generator, with headlight off only one coil is in circuit, with it on both coils are in circuit, the switching is done by the lighting switch. Finally have you connected the battery the right way round, should be POSITIVE earth.
Also worth checking switch is the correct one (if its been replaced) the positions are:
Off - Auxillary (Aux) & terminals 7 & 8 linked (note Aux has a fixing screw through it & is not earthed)
Head - 2 & 3, 5 7 & 8 linked
Pilot - 1, Aux & 8 linked
Note: terminals 1 5 & 6 are permantly linked.
Hope this helps

[blackshiver]

Positive earth?

John.
My 20DC had negative earth when I acquired it. It runs fine, the lights work but I'm not convinced the battery is charging.
It has a remote ignition coil and as well as the "two pin plug" there is an extra wire from the engine running to a second "little square silver" rectifier.

Can someone explain the effect of running negative earth like this and then simply trying positive earth by swapping the battery leads over.

[John Wakefield]

20DC wiring/charging

There is no disadvantage/advantage in having positive or neg earth, the official Greeves wiring is Positive earth. You cant just change battery terminals over. To check the charging disconnect one of the battery termials & put a ammeter in line. There should be a small charge without lights on & with them on it should balance out the discharge. You can also check it by putting the lights & rev the engine, lights should come up brighter.

[blackshiver]

Into the wiring...20DC

This is what I'm starting with (attached). The engines getting the Nametab treatment so I'm looking at the wiring I should have sorted ages ago (you know, crimped, scotchblocks and quite nasty but working) except..I think.. for the charging).

I have the wiring diagrams in the A4 Villiers Engine reprint but the rectified one has a "off P H Direct" switch and its negative earth. The direct one has a "L Off H" switch.

So I'm confused and have not warmed up the soldering iron yet.

Do I have an odd switch or is are the wiring diagrams to pot?.

The MDS was much easier John...no wiring.

[John Wakefield]

20DC wiring/charging

Here is a link to the Villiers 9E/32A wiring diagramm, http://www.villiers.info/picpop.php?part=AGW32r as you say its Neg earth.
As you say it has the extra DIRECT position on the switch. I would assume the switch you have would be ok but you would not have the direct lighting function. Sorry I cant help futher as I im not familiar with the wiring on the singles. I would suggest you get a Greeves wiring diagram for your bike (the one linked is a general one, individual makes of bike may vary) & re wire it according to that.

[John Wakefield]

20DC wiring/charging

Having asked someone in the know, apparently its easy to change from pos to neg earth if you use a modern block type rectifier, ie Maplin part No AR82D price £2.39. These have 4 connections (not three as per the old type selenium rectifier in the Greeves or Villiers diagram). Connect the AC connections as per diagram to the AC termials of rectifier & connect the DC ones + to battery positive, & - to frame (earth) The block type rectifier does not need to be isolated.
You then have a negative earth system.

[Les Pilgrim]

25DB Electrickery!

Hi ,its me again,and I apologise in advance,if I seem to have missed the obvious,in the lighting problrms comments, but ,as I have pos earth on my bike,and i have all the lights, horn etc,working OK,AND, I have one of the silver box rectifiers,(Maplins) referred to,(the selenium disc one IS jiggered!),retaining pos earth ,do I connect the terminal marked + on the rectifier,to the frame,(earth),and the remaining,(opposite) terminal), to the battery _ lead,?,or have I got that wrong?.Any conirmation or correction will be most helpful,as I dont want to damage the Maplins item, by connecting it wrongly.
MERRY CHRISTMAS EVERYONE!
Les.

[John Wakefield]

25DB/DC wiring

If you wish to keep it positive earth then + to frame & - to battery but you may need to isolate rectifier. I would advise making it NEGATIVE earth buy putting + to battery & - to frame. My 25DC is wired like that. There is no advantage in having positive earth, it was at the time thought to reduce corrosion of battery terminals but proved a myth, hence all modern vehicles are neg earth. It also makes things easier if you want to connect in any polarity sensitive accessories such as a sat nav, although I dont think these will run on 6 volt

[Les Pilgrim]

25DC Lighting

Many thanks for your,"Lightning,",lighting,response!.Really helpful,and much appreciated.
The bike now has a Certificateof Authenticity,(required to get such an imported vehicle,registered here in NZ,and I shuold,fingers crossed,be riding it in January,(it's Summer here now,and just the right conditions, for an enjoyable spin!)
Thanks again,
Les.

[PhilT]

Hi John 25DC Wiring again

Have found your updated 25DC wiring diagram under East Coaster - much clearer than the old one, thankyou. I have the 25DC that was sold by Charterhouse at auction October 2019. It is not as good as it looks and it has had the common rewiring effort by someone totally clueless as usual which I am trying to correct. I haven't tried to start it yet as there is no spark at the contact breaker so I thought I'd better sort out the wiring first. The lights and horn now work which is a positive start.
Couple of questions:

1. The engine plug has 6 holes. I think somewhere else you recommended leaving one wire out to the plug but I can't find that again in the Forum. Having rewired it according to your diagram with 5 wires going to the plug, which position on the plug should be blank assuming that R(red) is 1 and going clockwise?
2. Is the view of the plug from the top as it enters the socket?
3. I have bought a new Rectifier, though Maplins no longer do one. This one was on eBAY for £5 new and advertised as "

Greeves 3T Villiers 324cc . solid state rectifier. item no.

223746723151

"

.

The advert said that it was suitable for "alternator" rather than the dynamo fitted. I have assumed this is not an issue.
I have wired it as +ve earth, -ve feed from battery. When I check the thing should i be getting current out on the other 2 connections, i.e. Red wire and Black wire to Engine Plug? I'm not when checking with a simple 6v lamp earthed to frame.

Thanks
PhilT

[John Wakefield]

Greeves wired positive earth but I wired my bike with neg earth as it seems more logical for positive to run along the wires and earth through frame, I think this is the thread with the details you want https://www.greeves-riders.org.uk/fo...iring+diagrams The main thing is that the five wires correspond in the plug, leaving one set blank on a 6 pin plug. The rectifier is the right one, I have bought one from that seller.


Second diagram has a Lucas switch but is useful as it shows the coil connections inside the engine.

[PhilT]

Many thanks John. 2nd diagram useful for my understanding.

1. I am still unsure about the engine plug wiring - are the wiring colours as they enter the plug, let's call it "top view" as "plan view" is not clear?

2. Again on the engine plug, I have assumed that position 2 is blank

based on the wiring plug being from the "top view" as the wires enter the plug and

assuming that red is connected to position 1 and going clockwise. Is this correct?

3. On the lighting switch as 8 and Auxiliary are not linked I have kept the back light working by staying with the red/white wire connected to 8 (actually a delightful shade of pink from the back light on mine but too much of a pain to replace with correct red/white!).

Thanks PhilT

[John Wakefield]

Plug is looking down from top (the side wires go in). You need to wire the plug so that the corresponding wires as fitted to 5 way plug/socket correspond to the 5 way diagram The important thing is that the wires match. If you have 6 wires to crank case socket I cant really help as I have experienced the 5 way one

I have now found the official 25DB/DC Greeves wiring diagram with 6 pin plug/socket (attached) so that should help

Note I have reposted the pic of my 25DC/25DD diagram in my original post as two of the connections were wrong, you may need to combine the drawings to arrive at correct connections for the 6 way plug/socket

[PhilT]

Thanks John. I will have to combine the drawings as this 6 wire plug one seems to throw up more questions such as there is no wire from battery to Capacitor, and Auxiliary is connected to headlight but on my switch has no supply to it, and no stop light is wired(though that is straight forward). Ah well, I can play with them and see how I get on - at least I can be sure of positions of wires in the engine plug now.