In my experience you cannot kickstart the bike but a good hill bumpstart will work. Any 2MC left now will be too old, use a modern alternative and it may work. You are looking for say a 68K Micro Farad 50V capacitor
Once I got the motor running (I was barely able to get mine kickstarted on a almost dead battery), I was not able to use the headlamp or turnsignals, without excessive misfiring. Later on I also found the 2mc was also shot (the voltage drained off in 2 seconds).
Knowing the battery and 2mc were bad, I'm amazed that the boyer was able to run! (must have been the new high output generator with the tympanium regulator)
I would be surprized to find that the capacitor lasted even 2 seconds.
That's really all they do is store a little jolt, they are designed to work with a functioning charging system. Your capacitor is probably still good.
I left some details out, the capacitor was removed from the electrical circuit, charged with a battery, left for five minutes and had no voltage. Then I left the voltmeter connected, charged the capacitor again and when I disconnected the battery, I got to watch the voltage rapidly go away. A perfect capacitor, out of circuit, would hold the charge forever.
In the real world a new capacitor should hold the charge for hours. Less than five minutes, as described in the manual, means the capacitor is almost/already dead and needs to be replaced.