+ve supply to Bosch CDI unit.

G

ghwallice

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Location
Ipswich
The +ve supply to the Bosch CDI HTK unit. The red wire. Normally comes from a centre tap on the 3rd stator coil, but I've fitted the bike with 2 BTZ type charge coils.

One would assume that it would be +12v DC, but then when one makes assumptions, things fckup. Is it ok to supply this with +12V DC via an ignition relay?

I put my new toy (Cathode Ray Oscilliscope) on the pickups, and, just winding the motor over on the start button, they are each giving me a nice little 6v peak to peak sine wave with duration of about 25mS.

Regards, Greg
 
ghwallice said:
The +ve supply to the Bosch CDI HTK unit. The red wire. Normally comes from a centre tap on the 3rd stator coil, but I've fitted the bike with 2 BTZ type charge coils.

One would assume that it would be +12v DC, but then when one makes assumptions, things fckup. Is it ok to supply this with +12V DC via an ignition relay?

I put my new toy (Cathode Ray Oscilliscope) on the pickups, and, just winding the motor over on the start button, they are each giving me a nice little 6v peak to peak sine wave with duration of about 25mS.

Regards, Greg
Click to expand...

Reckon the name says it all; HKZ=Hochspannungs Kondensator Z?ndung=high tension capacitor ignition, ie, capacitor discharge ignition.

Pretty sure +12V won't be enough.  The CDI unit is supplied with high-tension via the red wire from the stator coil, the warning stickers aren't there for nuthin... :D  If they were supplied with only 12v from the stator, they wouldn't go tits up at the slightest ingress of moisture in the connector.

You will require ignition boxes such as the later BTZ units, lots of those kicking around.  These work off +12V.  BTZ=Batterie Transistor Z?ndung=battery transistor ignition.

piet
 
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