Hello Lads, The HKZ, with exciter coil and alternator regulator in copper iron, has a period uniqueness about it i actually like and admire. Power semiconductors of the period were rare and required careful design into something like a motorcycle, reliability was difficult to achieve for many reasons. Hence the HKZ/alternator solution was deemed a reliable solution, and save for the first installed inverted control box, it was reliable (*).
Harry, there are many and all sorts of aspects that would give the readings you have, from actual Laverda bike specific to how or what meter you are using. As with many aspects of life, easy things first is a good approach, perhaps you do that already. Lads have indicated items to follow through on and with. Am the messenger in regard to how a HKZ regulates the charging current, 18V is not a wanted value at any time, on a charge system. Voltage current interaction is a complex subject, not for this forum to my mind.
Stefan, you are a dedicated man in retaining the Bosch system or parts of it, have a special triple here that will retain the HKZ as fitted, there are good reasons at times. Shottcky diodes have a lower reverse voltage rating than usual power diodes, no news to to you there. There is the possibility of "load dumping" on the alternator coil when the motor stops, up to minus 80Volts is possible applied to the diodes. May take out the Shottcky diodes. Those ND FET RR's, i suspect that they use synchronous rectification on the stator input, ie the actual rectification is done by fets turned on and off in phase with the incoming AC at the frequency of the motor derived rpm. Very efficient and power fets are robust these days. Dig out an old email and post it here for those interested. The ones i have installed work very well to date.
(*) Whom remember the old theatre lights that sort of staggered their way to being dimmed? That was done with copper and iron only, the creaking/staggered dimming was down to a section of iron mechanically activated, closing a gap in a bigger iron circuit with copper winding, Saturable reactor, needs must at times and the needs were many for Laverda at the time.
OLD email on FET RR.
Not sure about the honda fours ( what do you have by the way? ) and the RR fitted. What i do have is a working knowledge of batteries. You actualy need a higher voltage on AGM batteries than flooded acid cell type batteries. Hence why modern RR's run at about 14,2-14,4 Volts output. You can get lower output voltages in RR's for use with flooded cells. Possibly the often misunderstood sense wire on RR's like the Shindengen SH530-12 is the reason for over volted charging systems, on Honda's, however i am not certain, not being present to see what is happening.
Doner RR's are many these days, i just picked up on ebay from the USA a Shindengen FH008EB, this is a FET type RR as opposed to the SCR type ( SH530 ) of the last 30 years on motorcycles. About AU$80 delivered here. If i were you i would get a modern RR, say from sports bikes of the last 2 years as the price difference is nothing compared to the power handling of the modern RR's such as the FET units. You can fit a high powered RR to a lower powered stator, no problem with voltage regulation. The FET type above came from a 1 or 2 year old Blade 1000.
HTH John.
