The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: duTch on 05.08. 2012 13:56

Title: Pattern Regulators- maybe a Caution??
Post by: duTch on 05.08. 2012 13:56
     I've been meaning to do this for a while,but, a while back, I bought a Pattern regulator, (variation of it seems a RB 107),  which mechanically on the bench seems to be ok though not yet on the bike.
 When it first arrived I thought to see if my old brass cover will fit.?..NO..! and today I explored even further.
       The cover isn't high enough, and interfered(by about 5mm) with the 'bridge' that goes from top of regulator bobbin to 'F' terminal.
     Furthermore, same at the other side, where the series coil starts at top end of Cut-out 'bobbin', is too high and the cap sits right on it too.
   The way I see it, is that both of these will bridge 'D'+'F'+'A', straight to earth, through the cover, and mess up something?
    I can post photos tomorrow if need be, or am I just wrong??
 Also Trev, early last year you posted ;
Re: Regulator Box
« Reply #5 on: 13.01. 2011 22:16 »
   Reply with quoteQuote
The rubber mounts were only introduced with the RB107 regulator.
The early MCR1 & MCR2 were bolted to the frame with no rubber cushion.
The "frame" or "chassis" of the regulator is directly connected to the "D" output of the generator.
I'm just wondering, because as far as I can figure the one I bought (I call variation~RB 107) looks same as a MCR2 from outside,different insides, with spring clip on cover, and no rubber mounts, and the RB 108 has the rubber mounts on side of cover, but same internals as the 'RB 107'?
Also, I don't know if this Lucas literature is in the archives, but is worth a look and a save. (
Sorry if that's a bit long winded, cheers duTch
Title: Re: Pattern Regulators- maybe a Caution??
Post by: trevinoz on 06.08. 2012 03:57
                  The pattern regulators have a similar mechanism to the RB 107/108 but are a replacement for the MCR2.
However, the late version of the MCR2 has the RB 107 works as well.
Would be a good idea to make sure the points are clean before you use the reg. It will probably need to be adjusted also.

Title: Re: Pattern Regulators- maybe a Caution??
Post by: bikerjohndavies on 06.08. 2012 08:16
A friend and I have now used 4 of the pattern regulators that can be purchased in the UK for different bikes. The first one I bought was to be attached to my rigid B33. I connected it to the loom and left it dangling whilst I started the bike to see if it worked. It worked a treat so bolted it to the rear mudguard and started her again. No charge. Took it off again, checked the wiring and started her again with the new box dangling and it was charging. Bolted it back on and no charge. After lots of swearing and trying different things it turned out that the clip on cover was just touching one of the contacts inside so earthling it out when bolted to the bike. A bit of insulation tape inside the cover cured the problem and the regulator has been working fine for a couple of years. All I can say is that we have found the same problem with all of the ones we have purchased but at least we now know what to do to cure it.

If you fit one and get no charge just try taking the cover off and see what happens before swearing at it and chucking it out the window.
Title: Re: Pattern Regulators- maybe a Caution??
Post by: duTch on 06.08. 2012 10:35
Thanks John,
       You're re-iterating what I'm saying, have attached a couple of photos front and back views with my old cover one side and the one came with it other side,which is much shorter(~5mm).
  I carved a bit off the reg bobbin side to clear, the cut-off side is close but just ok I think(with my old nice brass cover-the new one's not worth a cracker).
 Trev- Thanks , it seems to work ok cut-off wise,doing on-the-bench test, as I said in another thread the other week, reg. side will need adjusting when on the bike volts seem a bit high- that's the (reg-bobbin)spring adjuster I think?
   Far as I can tell the difference is just the D-F resistor is a coil type, otherwise points on top, which makes me think I've maybe been supplied with the wrong cover?
 It'll be a bit before I get to that, so no need to rush in, but all ideas taken on.
Cheers for now duTch