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Original Post (Thread Starter)
#879284 05/02/2022 3:53 PM
by dave j
dave j
My 67 Triumph has the two condensers in the points cavity and two more under the tank. Am I right in thinking that if the two in the cavity are no longer working then the two under the tank won't make any difference to sparking at the points because they can't just take over? I was reading about this in an old thread but don't properly understand it. I can't see the point of the extra ones if they can't help.

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#879290 May 2nd a 05:32 PM
by quinten
each pair of condensers , on either side , works in parallel .
1.if either condenser fails "open" ... the remaining condenser will do the work
( one can work without the other )
2. if either condenser fails "closed" ... its a short to ground ( big enough to blow a fuse
or small enough to prevent the ignition from sparking )

3. only one condenser is needed in the circuit , the one on the points plate is necessary
as a mounting point for the points spring and + side coil wire .
a. aftermarket condensers for this spot are fussier to fit , because they slightly changed the thread boss at the base .
It's easy to mess this up and accidentally ground out this connection .
b. ( you can get rid of this condenser by making up a dummy condenser ,
that has the threaded end , and is insulated with epoxy , and no condenser guts )
... the remaining condenser at the coil can do all the work

4. It's kind of a coincidence of Manufacturing that they rolled out and fitted the extra condenser at the coils
Before the condenser at the points went away ... as both of these condensers are not needed .
( lucas was also chasing ignition problems in 1967 , when most bikes when to 12 volts ,
so maybe they thought the extra condenser was helping )

5. the 4CA kettering points cam is a known engine killer , when run at 12 volts .
( the 86° cam allowed for extra sparks ( pre- ignition ) when the points closed
... that can cause overheating of pistons to the point of power loss and seizure )

6. I wouldn't use a 4CA 86° points cam , and if i did . I would drop the voltage to the coils
with a 1.5 ohm ballast resistor ... and change 12 volt coils out for 6 volt coils .
This lowers the voltage across the points by half , from 12volts to 6 volts .
Doesn't seem like a lot , but it is when switching an inductive circuit .

7 . there is also a 4CA ET cam . when used with ET ignition its a completely different system
that had none of the 12 volt Kettering problems . Coincidentally you can use this cam at 12 volts .
where it will severely over dwell the coils , but if they don't overheat in crap out , will work fine .
( supposedly , back in the day , this was race modification ? )
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