Topic: CB350 K4 Twin - permanent magnet alternator???

[lordmoonpie]

Does anyone know if the CB350 K4 twin has a permanent magnet alternator or not? I understand teh CB750 doesn't but does the CB350?  Ignition problems may be all as a result of this so I'm keen to rule out another possible root cause

[kirkn]

Yes, the 350 twins have permanent magnet alternators.

[bryanj]

Yes plus from memory a complicated RH switch that alterd the charging output

[kirkn]

Yep, there were / are two separate charging coil circuits surrounding the permanent magnet rotor.  One is always sending current to the rectifier to charge the battery regardless if the lights are switched on or switched off.

The second coil's output is added in and sent to the rectifier when the lights are switched on at the handlebar.  That second coil's output could be permanently switched in by connecting two wires in the headlight shell.

The 350s (and all the Honda twins and singles) used that kind of set-up and they ALL will develop poor ignition performance if the battery is not kept in tip-top shape.

Good luck with it.

Kirk

[scottly]

Simon, this is why I asked you for a schematic of the bike your charging system came from; so I could tell if it was indeed permanent magnet, and maybe help give you some insight as to how to wire it up to the power box and minimal battery.

[lordmoonpie]

Simon, this is why I asked you for a schematic of the bike your charging system came from; so I could tell if it was indeed permanent magnet, and maybe help give you some insight as to how to wire it up to the power box and minimal battery.

Problem is Scottly, my diagrams of electrics would probably confuse things more! I ask this question becuase I'm having a debate with Boyer themselves now as to whether their product has the correct setup instructions and they have now stated that if there wasn't a permanent magnet alternator in use (as in all 750s) then the power box won't work. If that's the case, I have to question why they freely sell the powerbox and ignition as a kit for SOHC 750s if they KNOW it won't work!!

My 350 setup having the permanent magnet (Thanks guys for confirming ) means they will have to do some more thinking for me...

[bryanj]

I have the proper Honda manual for CB250.360.CL360 part number6136903 which has wiring diagrams for different countries, I could scan and e-mail one of those if you want, just pick a country

[scottly]

I have the proper Honda manual for CB250.360.CL360 part number6136903 which has wiring diagrams for different countries, I could scan and e-mail one of those if you want, just pick a country

Thanks, it might help, although it would be nice to have the schematic for the 350, just in case Honda threw in a ringer...
I'll PM you.
Scott

[scottly]

I have to question why they freely sell the powerbox and ignition as a kit for SOHC 750s if they KNOW it won't work!!

I think you may be confusing the transistor box that comes with the kit with the "Powerbox", which is a separate part for use with permanent magnet alternators. If you wired the stator of the alternator to the transistor box, this would explain your erratic timing. In the instructions for the ign kit, the stator they are referring to is the plate with the pickup coils that replaces the point plate, not the alternator stator. 

[lordmoonpie]

I have to question why they freely sell the powerbox and ignition as a kit for SOHC 750s if they KNOW it won't work!!

I think you may be confusing the transistor box that comes with the kit with the "Powerbox", which is a separate part for use with permanent magnet alternators. If you wired the stator of the alternator to the transistor box, this would explain your erratic timing. In the instructions for the ign kit, the stator they are referring to is the plate with the pickup coils that replaces the point plate, not the alternator stator. 

No - not confusing those Scottly - they are wildly different parts. Boyer confirmed my setup is correct based on photos but suggest I time the bike by laying all four plugs on the head and run the starter like that with fuel off. Seems a less than orthodox way to do things if you ask me. Anyway, I've finally decided that if people as good with thes engines as Mike Rieck are using a dyna 2000 then I should be too. Mike's sourced me a replacement and I'll be sending him the green tonight!

Once installed the Boyer and power box will be up for sale - barely used