Commander ignition systems

[Ian]

Hello all. I'd like to ask the collective's opinion about these.My 1992 Commander still has the original Boyer unit fitted and appears to be fine. My questions concern what happens next.I'm a bit worried that because mine hasn't failed it must be about to. Strange logic but true. So, the questions:Is it living on borrowed time and overdue replacement?If so, do I do for one of Graham's well-respected Minimag units because it's a straightforward replacement, orDo I go the whole way with one of Andover Norton's digital systems that includes new coils, etc?Whilst the Boyer must have been fine when the bikes were new (or were they all that was available?) and mine's been fine, why did Norton Motors go to the trouble of developing their more sophisticated system? Surely resource wouldn't have been used to design it if a Boyer/Minimag replacement was fine? If the digital one is better, in what way? Does it justify it's price?Now, finances aside, do I replace my Boyer, and if so, with which system? For these purposes, please ignore the cost implications; I'm after the 'best' one!Thanks in advance.Ian

[johnbirchjar]

Hi Ian,I replaced the Boyer unit on my Classic many thousands of miles ago with a Minimag one,the main drawback was the Minimag did NOT have a wire for the Ignition light ,so in the event of charging problems(of which I had a few)my first indication of a problem was a flat battery ,I have since overcome this problem by fitting a voltmeter ,I know Commander's are wired differantly but in my experiance the Minimag is a reliable piece of kit,rgds,J.B.

[Richard Negus]

Ian,As I was directly involved in all the Norton ignition systems, I can offer this for you.The first Norton rotary ignition system was the Sparkrite CDI, later enhanced with a separate retard box, fitted as original equipment to all Interpol 2's.The ignition unit, matching voltage regulator, retard unit and trigger were manufactured by a small company in Birmingham and were not totally fault-free. The boxes were not weatherproof, allowing internal corrosion and some allowed the smoke to escape (see Lucas thread). Paddy Ryan in Shenstone's inspection became adept at repairing them and, after Sparkrite had ceased trading, continued to assemble a few new ones.Before the eventual demise of Sparkright, Norton started discussions with Boyer for a replacement system. This sytem was first used on the Classic and later on the Commander and F1 and introduced inductive 6 volt coils and the dreaded Lucas ballast resistor. Boyer supplied the ignition unit and flywheel trigger, the only difference between Classic and later units was the rev limiter, set at 8,750 for the Classic and 1,000 higher for the others.Initially good, problems in service demonstrated that the ignition unit had to be kept , the ballast resistor had to be kept dry, and all the wire connectors had to be kept clean. The Commander installation, particularly, did none of these; the ignition was sandwiched to the voltage regulator (mea culpa) like an electric blanket, the ballast resistor had rain directed at it by the fairing, and all the ignition wire connections were difficult to access without major dismantling of the bodywork.The Minimag ignition unit is an excellent like-for-like replacement for the Boyer unit, but doesn't solve other problems in the ignition system.The Norton digital system, developed in conjunction with Minimag, addresses all of the problems encountered in service with Boyer systems:.Sparkrite and Boyer flywheel triggers are, to the best of my knowledge, NLA.Sparkrite and Boyer triggers require an air gap to the flywheel of 0.04 mm +/- 0.05.Norton flywheel sensor is an encapsulated automotive part made by the million and requires an air gap of 2.00 mm +/- 0.30. It is fitted with a long lead and an IP68 weatherproof plug..Norton ignition unit is a fully-sealed metal casing fitted with IP68 weatherproof connectors.Norton system dispenses with the ballast resistor and uses inductive 12 volt ignition coils.Norton system is supplied with a separate wire harness to connect all items together, including soldered ring terminals at the coils.There are many rotaries with Boyer (and Minimag) systems that continue to perform faultlessly, and I would be the first to agree that the Norton system may seem overkill. I no longer have an axe to grind either way.R.

[Richard Negus]

I replaced the Boyer unit on my Classic many thousands of miles ago with a Minimag one,the main drawback was the Minimag did NOT have a wire for the Ignition light

Hi John,Have you stopped taking the tablets ? The ignition warning light wire comes (came) from the voltage regulator on IP2's and Classics. No other Norton rotaries have that useful feature.R.

[Ian]

Richard, many thanks for this very complete summary.One final question, if I may.You say that many Commanders perform admirably with the Boyer and Minimag systems. Mine has a Boyer, which seems to be OK. I'm happy to change it if it is considered life-expired but really I'm not sure if it's anywhere near it's service life yet. Not wishing to get stranded, I'm wondering (probably for the wrong reasons) if I shouldn't change it to be on the safe side.What do you think?Ian.

[Richard Negus]

Ian,Difficult question! Some days I take the view " If it ain't broke, don't fix it" and other times I'm glad I have "get-me-home" RAC membership. Only once, up in Scotland, have I needed it as, even with a workshop, I couldn't have fixed the bike there.The Boyer hasn't failed in 25 or more years (I guess) so is unlikely to fail now. Making an extension lead and moving it to a cooler location will make this even less likely.The Lucas ballast resistor deteriorates gradually until corrosion in crimped terminals makes it go open circuit. Easy to identify (press starter button, engine starts; release button, engine stops) and relatively easy to replace. There is an Indian or Chinese version, slightly larger, which has screwed terminations of the resistor wire rather than crimps and is far more resistant to corrosion.R.

[johnbirchjar]

Hi Richard,the original volt regulators may have had three wires,(red black and yellow?)but all of the replacements I have fitted(three up to now)have only had two,(red and black) when I quiried this from the supplier I was informed that ALL volt regulators now only have two,and when I asked "How can I tell if I have a charging problem?" the answer was,(and I quote)"The battery goes flat".I expect there is a way to wire the ign: light using the red wire but to me electrics are akin to alchemy ,hence the fitting of a volt metre.rgds,J.B.