[mtrude]

Hello, can someone tell me where the location of the rectifier should be on 1961 Clipper 350? Mine has been relocated to between the fork clamps.Also is there a clearer version of the wiring diagram available? I am trying to reconnect the alternator and I am unable to read that portion of the diagram available. Thank you.

[AzCal Retred]

You are aware of Hitchcock's Royal Enfield online supply? Hitchcock's provides a downloadable manual with wiring diagram for the 350 Clipper here, Pg. 37/82:

https://accessories.hitchcocksmotorcycles.com/core/media/media.nl?id=238077&c=1062795&h=fd85fdd2a5911fc2a759&_xt=.pdf

Do you have a VOM meter? Does the machine have a magneto? The original rectifiers were silicon, have you tested yours to see if it's still functional?

My 250's rectifier was in the underseat area. It requires airflow, which might explain the relocation.

How about a few pictures? That will clarify things.

[Mark M]

Two possibilities for the rectifier, probably on a bracket (part number 45117) under the front of the tank or just possibly under the toolbox on the right side. Most likely the bracket I think!
REgards, Mark

[mtrude]

Thank you for the replies I have the wiring diagram from Hitchcocks but I cannot read the color coding on the leads coming from the alternator. Its too blurred. The leads on my alternator are white with green tracer, green with a yellow tracer and green with a black tracer. my best guess so far is that the WG goes to the rectifier and then to the lighting switch. The GY goes to the ignition switch and the GB goes to the rectifier. Maybe.  If the lighting switch does the combining of the windings output does it matter which wire goes where? I have a VOM and the rectifier failed the test as described in the Lucas electrical equipment service manual.The rectifier is located on a aluminum angle mounted on the lower fork tree, similar to a zener diode mount.  Very vulnerable. The wiring is of adequate length to reach this position? I dont see a bracket or mounting point under the tank? and looked for that part number and didn't see it? There is a tab above/behind the airbox on the right side but appears something should slide over it? I'm sorry I dont have the ability to post pictures.  I could email them to someone. Thanks Mike

[AzCal Retred]

The 350 Clipper WD and section shows the 6 alternator coils wired as 2 pairs. One pair is two coils in series. The second pair is two seriesed coils in parallel with a second set of seriesed coils, the same as the first set but double.

So - after 60 years of owner repairs, we need to do some detective work.

One wire will be the common connection point. You need to ohm-out the 3 leads and build a "truth table".
Read the lead resistance between GG, GB & GW. One pair will have the lowest reading, hopefully over 1 ohm to be readable. That should be the paralleled pair(B//C pairs). A second pair will be almost exactly double that reading(A pair), that will be the other pair.
The 3rd reading should be essentially 3x your lowest reading(Thru A & B//C). Those leads are the coil "ends", the remaining lead is the common.

In 1960 the lighting switch did some real AC voodoo. The switch shorted B//C and let A charge during daylight running. Shorting B//C via AC inductive effects reduced the output of A. When the pilot lamps came on for evening running (a British thing...) B//C coils got un-shorted (left open circuit) to increase the A coil output a bit. For full night time lighting charging, B//C coils got paralleled with A coil. All this happens in that rocker switch part of the lighting switch inside the casquette or headlamp shell.

Plan "A"; As the old selenium rectifier is dead, I suggest you at least invest in a modern rectifier:
https://accessories.hitchcocksmotorcycles.com/16402?cont_page=accessory-shop/Charging
PART No. RECTIFIER; SOLID STATE RECTIFIER, 6V; £6.71

This is a POSITIVE ground system as is, so be aware. I believe that there is no actual voltage regulation on these machines, that's why they ultimately depend on the lighting switch to "control" battery charging by controlling stator output by depending on lighting load.

Plan "B" is to find/make a 2:1 AC transformer (6V/12V 60W) (120V/240V 600W) and use it to double the existing stator output voltage, then use a Lucas Reg/Rev and convert the system to conventional 12V negative ground. The internal common leg becomes one AC input, you parallel the other coil outputs then feed them into the rec/rev as the other leg.

Plan "C" is to just get the 120V Lucas alternator & rotor or compatable Indian Bullet alternator and current tech 12V Reg/Rec.
https://accessories.hitchcocksmotorcycles.com/37670?cont_page=accessory-shop/Charging
PART No. 200004F; REGULATOR/RECTIFIER, LUCAS (SINGLE PHASE); £36.00

ID your stator wires and let's move ahead.

[Adrian II]

Plan "B" is to find/make a 2:1 AC transformer (6V/12V 60W) (120V/240V 600W) and use it to double the existing stator output voltage, then use a Lucas Reg/Rev and convert the system to conventional 12V negative ground. The internal common leg becomes one AC input, you parallel the other coil outputs then feed them into the rec/rev as the other leg.

AC Transformer? What?? NOOOOO! totally unnecessary!

Standard Lucas alternator 6V to 12V conversion as follows, have done this myself on several bikes.

Just wire the stator so that it is permanently on full output and put it through a 12V single phase reg-rectifier, which you can wire for -ve OR +ve earth/ground.

With your stator wiring colo(u)rs the Green and Black and Green and Yellow wires are joined and connected to one of the AC wire on the reg/recfifier, White and Green is joined to the other AC wire on the reg.rectifier. You can use a separate rectifier and zener diode for voltage control if you REALLY want to.

If your alternator is working, congratulations, you now have the backbone of a 12V system. The wiring gets a whole lot simpler too.

http://www.norbsa02.freeuk.com/Wiringdiag12Vbasic.JPG

A.

[AzCal Retred]

A2 - So you've found that the 6V stator generally makes enough voltage to satisfy the modern 12V reg/rec? I figured a 1:2 step up at a a minimum. Cool Beans - that'll make achieving charging on my old 250 Fire Arrow project go easier when the time comes. That Lucas reg/rec just looks like it wants to be under the headlight to me. Cheers - ACR -

[mtrude]

Thanks again  everyone for the replies.  Just so I can understand what the stock system is,  lets stay with plan "A" for now. Here is what Ive found

w/g.           0.5.     1.0
g/y.    0.5.             1.4
g/b.    1.     1.4 
         
          w/g.  g/y.     g/b

vom set at 200 ohms
no leads grounded
 thanks Mike

[AzCal Retred]

The chart needs work. Assume "B" common, "A" is the single series pair, "C" is the double pair, it should read like this:

A      1.5     1.0      0.0

B      0.5     0.0      1.0

C      0.0     0.5      1.5

        C         B         A

You need to do a "lead tare" to know what minimum indicated ohms really is. Does your VOM read below a 200 Ohm scale, 0-20 ohm?

The common leg gives you the 0.5 & 1.0 ohm reads. The coil "ends" will be the 1.4 ohm read.

Running open circuit AC readings are very helpful. As long as it's over 13 - 16 VAC open circuit (common leg to end) it should run a modern 12V reg/rec module and produce something for charging. There's lots of voodoo built into modern electronics.

[mtrude]

My VOM does not have a setting less than 200 ohms. Am I correct in saying that the "Common, B, W/G" goes to the ignition switch, and the  two "ends", "A, C, G/Y G/B" goes to the rectifier and then  on to the lighting switch, with  A on the pilot circuit and C on the headlight circuit ?  Im getting confused a bit here. I am reading this from Hitchcocks  1960 RE 350 clipper manual. I will be able to take open circuit readings soon . Thanks Mike

[grumbern]

The 200Ohms means it can measure up to 200Ohms in this setting.

[AzCal Retred]

Mtrude - here's a simplified schematic of the charging system. Take out your existing switch and verify it operates exactly like the wiring diagrams in the downloadable manual. The 2022 diode bridge from H's will replace the 1960 Selenium unit. Myself I'd try AdrianII's way too; if it works on your stator output, things get way better. This old skool "switched coil" system looks like a battery eater to me.

Fill in your wiring codes for the A, BC & COM sections and you should be good.

When testing the open circuit voltages, the coil end to COM voltages may not be precisely the same for both coil sets. Reading voltages between the coil end-to-end outputs should be way lower than coil end to COM numbers. It's AC, so don't expect super accuracy or agreement.

Good hunting - ACR -

PS - Lower scaling on a VOM for resistance improves accuracy. Reading 0.5 ohms on a 0 - 200 ohm scale is less accurate than for a 0-10 ohm or 0-20 ohm scale. You use what you have, just understand the limitations. Digital stuff is pretty good, but do a lead tare to see what's also in the circuit you are trying to measure. It's enlightening to get a few precision resistors at the electronics store and read them with your meter. Battery condition can also affect the readings.

[mtrude]

Thank you everyone for the help. I have enough information to work with now. I may end up upgrading to the 12v system in the future, but Id like to use whats already here first. Ill keep you posted,   An off topic  question for the meter usage though,  could I place a 100 ohm resistor in parallel with my meter on the 200 ohm setting to get the lower test readings  into the middle and possibly more accurate range  of the meter?  This method is shown in the Lucas manual for some tests at higher discharges?  mtrude

[AzCal Retred]

Using a 100 Ohm resistor on an analog gauge in series would guarantee a mid-scale start, series resistance is additive. In parallel you'd be using the Parallel resistance formula: ( 1/Rt = 1/R1 + 1/R2 + 1/R3 + ... ), so 100 Ohms in parallel with 0.5 ohms results in 0.497 ohms, a result always lower than the lowest resistance in parallel. Series would work. Digital gauges are maybe less affected by end of scale issues, but it looks like a good strategy.

Let us know how this plays out - ACR -

[mtrude]

So, Sorry for the pause but sometimes life gets in the way. It appears that the GY wire is the two pair of coils and the GB wire is the single pair of coils , with the WG being the common. (maybe)I am currently filling in some voids in the harness as the previous owner removed some wire. I have tested the alternator output and found the following,  the readings  are in ac volts. This was with enough rpms to make the bike want to walk across the floor.  (no tachometer) At idle or just above, the readings of 30 were replaced with 10. I used a analog meter, and had to read between the lines.  So the zeros may be a bit higher, there was needle movement.

WG.  30    30   0

GY.    0.     0   30

GB.   0.     0   30
       
       GB.  GY  WG
 
Thanks trude