The manual says its "easily achieved using a 3 legged puller".

No, it isn't "easily achieved" as the cam has no flat sections upon which the puller can find suficient grip.

Anyone have a fool-proof technique for pulling the cam off the main shaft ?

TIA,
Ian

look for the correct cam-puller.
your cam has a 26x1 mm thread, the motobecane manual shows a combi puller (26x1 and 24x1 for the clutch)
wich maual do you use?

what do you plan?
i paid hard for buying a bike with a broken puller (it had a crack), it´s not an easy job to fix the puller on the right place.
don´t just hammer it back if you remount it, use a bit locktite.

I have never seen that in a Motobecane or Motoconfort manual. As MrMoby suggests the best is to buy the puller and just buy the two sided one so you can pull either the clutch or the cam.

many thanks for the advice. I was using the Haynes manual - this suggested it could be removed using a conventional 3-legged puller.

Would you have a picture of the puller ?

These are the three pullers - top is cam only, second is clutch, thisr is both. If you google flywheel puller it will come up with a number of vendors who sell them online.

Send me your email address in a PM and I will send you a copy of the Motobecane manual you need! Keep the Haynes though - it does have some good illustrations.

Is the magneto puller a left handed thread ?

Magneto puller 26mm 1,00 pitch right hand
Clutch puller 24mm 1,00 pitch right hand

ok, cheers Reb