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Boyer Ignition cb750

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philward:
Have been provisionally fitting the Boyer Ignition/mini coils to the CR Rep and when I fit the magnetic rotor, I've only got half a nut on the centre M6 advancer shaft. Surely that's not right. The instructions say if the rotor fouls the cover, to file the rotor so the advance and retard unit dogs fit in the rotor.
Has anybody else experienced this? I could just either cut the dogs off or time it up (few months off that/start up) and then file slots in the rotor to fit the dogs when the rotors in the right place.
Thought I'd ask first as if this is normal, why doesn't Boyer tell you to make the mod - seems strange

JamesH:
Phil - post a pic so we know what issue you're experiencing. The last time I fitted one I had to chuck the Boyer rotor in the lathe to open up the ID of it so it would fit over the shaft of the honda plate. Pull the plate off and see if you can assemble by hand and make share the tabs on the shaft are seating in the bottom of the rotor hole (make sense?).

philward:
Pictures are not that good - sorry

gp_st3:
I fitted the same kit about a year ago to my K4 engine and had the same problem - in the end I did away with the washer and that meant all except the last turn of the thread was covered.  Having checked that the cover to rotor clearance was about 2mm, I gave the nut a decent hand torque with some loctite and told myself at the time that I would go back and notch out the rotor to accommodate the dogs and increase the clearance 'later' but as with many such things, not got round to that yet!

It's actually a rather poor design IMO but the rotor is such a tight fit on the shaft (and has so little mass) that it'll never move.

The other thing I never did understand is why the instructions say to "time to the Full Advance Timing marks ... with the engine running at a steady 4500 RPM" when according to everything else I have read, full advance should be there by 3000 RPM (and the Honda Shop manual says 'above 2,500 RPM)

The thing is, if you set the Boyer to give full advance by 3000 RPM then at higher revs, the advance goes too far so it has to be done according to the instructions and to be fair, the performance is excellent so will remain a puzzle.

G.

philward:
Welcome G (noticed its your first post) - I agree about the design - all a bit 'home made ish'. I bought it based on the performance and longevity of design (had one on my Z1 in the mid 70's). I've got some half nuts so I'll fit one of those and loctite and peen the end of the M6 advancer shaft for safety. Poor design that you can't just fit it from the box though. I've modded wiring/connections and mounted minicoils as per picture

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