Author Topic: CB350 K4 Twin - permanent magnet alternator???  (Read 3692 times)

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Offline lordmoonpie

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CB350 K4 Twin - permanent magnet alternator???
« on: September 03, 2010, 01:15:28 AM »
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 ???
1994 Ducati 888 SP5
1951 Ducati 50cc Cucciolo
1981 Yamaha XV750 SE

Offline kirkn

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #1 on: September 03, 2010, 04:10:58 AM »
Yes, the 350 twins have permanent magnet alternators.

Offline bryanj

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #2 on: September 03, 2010, 11:51:45 AM »
Yes plus from memory a complicated RH switch that alterd the charging output
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline kirkn

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #3 on: September 03, 2010, 01:48:00 PM »
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

Offline scottly

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #4 on: September 03, 2010, 07:19:55 PM »
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.
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Offline lordmoonpie

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #5 on: September 05, 2010, 02:32:55 AM »
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 :D) means they will have to do some more thinking for me...
1994 Ducati 888 SP5
1951 Ducati 50cc Cucciolo
1981 Yamaha XV750 SE

Offline bryanj

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #6 on: September 05, 2010, 07:23:07 AM »
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
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline scottly

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #7 on: September 05, 2010, 04:41:57 PM »
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
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Offline scottly

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #8 on: September 09, 2010, 04:18:04 PM »
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. 
Don't fix it if it ain't broke!
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Offline lordmoonpie

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Re: CB350 K4 Twin - permanent magnet alternator???
« Reply #9 on: September 10, 2010, 05:09:20 AM »
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  ;D
1994 Ducati 888 SP5
1951 Ducati 50cc Cucciolo
1981 Yamaha XV750 SE