I am at present fitting a new Sparx stator, rotor and Sparx single phase regulator, rectifier, battery eliminator and a Boyer brandsen mk3 electonic ignition to my 1963 t120 Bonneville. The instructions are quite straight forward but the instructions for the Sparx regulator, rectifier states:-
IMPORTANT **Single & Three phase boxes*** Due to the sensitive nature of both the single and three phase boxes it is VERY important to fit spark plug caps of the 5000ohm resisted type. Failure to do so will cause overloading.
I donít understand what the spark plug caps have to do with the charging system. I am also concerned about using these spark plug caps with the Boyer Brandsen when I can find no other reference. I am also using new 6 volt coils. My question is am I better off using standard spark plug caps or should I use the 5000ohm resisted type. Any advice is greatly appreciated and highly regarded. Regards Coopers
It seems to me that Sparx are advising you to use resistive (AKA suppressed) HT caps because their own regulator boxes are susceptible to RFI (radio frequency interference). As to whether this as a problem for your Boyer, I don't think so. I say this because they sell the 5Kohm caps.
To confirm this, you would have to ring their tech support line on 00 44 1622 737040 between 4 & 5pm UK time. I just tried for you that's how I know. If you want me to ask, (due to the time difference), let me know. HTH Blapper
Coopers Your Boyer will work fine with the 5k caps. They won't hurt anything and the 5k resistance will prevent RFI from de-regulating your regulator, causing it to overcharge. The Sparx box is apparently susceptible to RFI which IMHO is a design fault. It is readily covered up by adding resistance to the plug leads.
RF interference is common, not a design flaw, to products that use modern electronic components.
The ignition, with its spark plugs and wires, is not the only source of RFI on these motorcycles. While the Boyer MKIII is typically immune to RFI from plug wires, the alternator wires can introduce RFI into the simplest MKIII Boyer box and cause it to faulter.
Any electronic device utilizing a computer chip is more susceptable to RFI. Thus the Boyer Micro-Digital and Micro-Power units need special attention, as well as the Sparx regulators.
It is one of the inconveniences we suffer to update our 50 year old motorcycles. John
I agree John ......but I believe that with internal shielding and internal RF bypass capacitors on the leads the boxes could be RF-proof. That would, of course, raise the cost and probably the size of the box. So I guess we could call it a design limitation.
John, I am just starting to renovate my T140 and adding a Boyer Power Box and Lucas three phase alternator are amongst my upgrades. When you say 'the Micro Power and Micro Digital need special attention', what special attention other than careful rewiring with single point earthing do I need to know about? Hope this isn't hijacking the thread, I figured any info would benefit coopers too. Thanks, Blapper
If you follow the instructions that come with the Boyer, which includes using 5,000 ohm resistor plug caps, you will not have any problems using the Boyer Micro-Digital or Micro-Power units.
When setting up your grounds, remember that the engine must also be grounded. Assuming that it will be grounded through its contact with the frame is not a wise thing to do. The engine is an important electrical path for the plug to establish a path to the electrical systems ground. Powder coated frames are the worse culprit for insulating the engine from the electrical ground, but corrosion can also isolate the engine from the electrical system. Both of these will cause the Boyer, or other electronic ignition to have problems or not work at all. John