SOHC.co.uk Forums > CB350/400

rotor

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AshimotoK0:
I agree with you Kev ....  rare earth magnets now make the permanent magnet rotor much more attractive (I recently rewound a Harley rare-earth P.M. aftermarket alternator and pulled 1.2kW from it,  as I upped the output voltage to around 200v  albeit for a non bike work project). Back in the day I had two 400/4 stator's go bad on me...both the same fault..... corrosion causing breakdown of the magnet wire lacquer insulation and hence a short circuit to the laminated mag-frame. The bikes were less than 10 years old when they failed. They run dry (like the 500/4) and I have never seen that fault with other Hondas that run in the engine oil.

The 3-phase system on the Honda fours is a brilliant system though IMHO because the system only powers the field coil  and induces magnetism into the rotor, on demand, as required. With a PM system, you have the constant magnet drag, which means you have to dump the excess power generated  with a 'crowbar type circuit ...or like on the Triumph twins from the late 60's onward rather crudely with a Zener diode.

I notice that DS now does an aftermarket CB400/350 four stator: On first glance it looks pretty well constructed.

 https://www.davidsilverspares.co.uk/CB400F0-SUPER-SPORT-1975-USA/part_322118/

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