Came across phils post which prompted me to try and give an understanding of the generator I sell.
I use the winding and moffset reg/rectifier that is also sold by electrex in their race alternator kit. The advantage is that the rotor is very small, which gives very low crankshaft inertia, no flywheel effect. ideal for us racers.
there is always a compromise though, the magnets in the rotor rotate past the stationary winding, to generate electricity, basically the faster the magnets pass the winding the more electricity is created, but because the rotor/magnets are on a very small dia, it means they pass the windings at a much slower speed for a given rpm. compared to a normal motorcycle generator alternator. (ie inside of a wheel rotates slower than the outside)
this is ok on my race bikes as I am not sitting about much and the bike is sat at high rpm most of the time,
and it works really well as the bike has no starter either, so does not drain the battery starting.
My big mistake was re-designing the special cover to allow use of starter motor, I have found that people think they ride their cafe racers on the road and think they will not be using lights and because they ride fast they will be revving high a lot of the time.
But I think the reality is that when you use the starter to fire up the bike you tend to use a lot of the battery capacity, and so putting back the charge used will need a good high rpm run without interuption to replenish charge.
for example, I had a customer bike fitted with my latest kit, with starter etc and my low profile cover and generator, I have been setting suspension and been bedding brakes in and doing runs between villages before handing over build, and I have found that general pottering about with squirts up dual cariageways etc stopping to fill with fuel etc just was'nt enough. the bike cruised along lovely, but generally speaking probably half the time it was running below the 3500 rpm minimum needed to put some charge back etc.
the bike would always start on kickstart, but the electric start would begin to struggle.
Its not the reg/rectifier that causes this, and the race reg/rectifier will not be suitable for a std honda system either.
hope this helps, the covers are expensive to make and coupled with the rest of the kit its a big spend, but saves that hole in the side of fairing, and saves you clouting the ground with the stock engine cover.
