Boyer Question

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Aug 19, 2003
This question is directed to Dyno Dave, but of course other feedback is welcome. I've had my current '73 850 Commando for two years and have ridden about 8,000 miles without a problem. I bought the bike with a Boyer MK III ignition installed. Recently I decided to install a Dyna coil. When making the change I found out that the 'black box' on my bike is actually the Triumph/BSA version!

Happy that the bike seemed to run fine, but wondering if it would run better with a Norton black box (or something else) I checked out your website for insight into the Boyer issue. In your 'Boyer Evolved' notes you indicate that the advance curves for the Tri/BSA and the sample Norton boxes seem to be the same ( over a disappointingly broad range) - overall not a ringing endorcement of the MKIII unit.

So my question is, assuming my current Tri/BSA box is basically the same as a Norton box is there any significant performance advantage to:

a. Switching to a Norton MKIII box at a cost of approx $90.00.
b. Completely switching to a Boyer Digital or Lucas Rita system at an even higher cost.

My 850 is in standard tune, with a single 34mm Mikuni. Using the current box the bike starts on the first or second kick, very rarely kicks back, does not backfire, runs strong (I think, not having been on another Norton in over 20 years) and gets between 50-60 mpg while running at 60-65 mph. In my opinion a very modest increase in performance would not be worth the cost/hassle of installing a completely new system. What do you think?

NC Commando
boyer MKIII

Enough contacts with boyer by others have convinced me of their statement that the only difference is the connector style. OK, years ago I had tested a tri/bsa unit that was substantially different. Foolishly, I thought it was intentional rather than just one extreme of the production tolerance. Not a ringing endorsement for sure.
If your device, where ever it sits in the spectrum of igniton curves, works for you, then any further purchases would only be in an intellectual pursuit and cost you money.
In general, I feel for the 8.5cr 850's respond, OK with the MKIII boyer (not including the E-Start).

I have given further though about the micro digital curve, and it is only theorizing about reports of owners, rather than direct testing and feel, if it set to 28-31 degrees (5000rpm) on a norton, it is way to retarded at low rpm/idle. I have no interest in using one on one of my bikes(norton twin). It may be fine on a slow burn/tall combustion chamber BSA or Triumph.

I am sure if installed on a bike the MD runs and goes down the road but until I fix my dyno readout and do tests, I only am going by gut feeling and judgement based on past experience. So if you know someone who has done actual dyno work with this unit on a norton I would love to hear the results.
Dave Comeau
Dave, Thanks for the reply. I'll stick with the current box for the time being. Reading through everything I can on the issue, it seems like keys to good performence with the MKIII unit are: a. Solder (don't crimp) the connectors on. b. Keep the battery charged.
boyer pick up stud mod

Actually, I recommend unsoldering the leads from the board. Scrape clean the board. Then I screw in some #4 brass screws, add lockwashers and 2 nuts. Then I solder the brass screws to the PC board trace.
The wires get eye lugs.
If they were to break you can still field strip the wires and reconnect to get home.
It's what I thought boyer should be doing on new product. They didn't ask me however....
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