[John Cole]

Many thanks for the replies to this problem, I did buy a tap in order to thread the sprocket centre and use the clubs extractor. Unfortunately the sprocket has been hardened and apart from softening and then re hardening (which starts to get complicated) It was impossible to get the tap started, even when using my lath. As its not a job that will need redoing very often I will leave as is. Many thanks again John.

[Thomas]

Hi John, I'm not sure if I understand this correctly, but the picture shows my self-made puller made of screws and nuts.
Cheers, Thomas

[John Cole]

I have trouble removing the sprocket on the magneto, as there is no internal thread on the sprocket itself. It is too close to the casting to get a puller onto it. Therefor I have to undo the magneto holding bolts to get a 2 legged puller engaged.
You can imagine the time it takes to get the nuts back on.  My bike is a 1914 3.1/2 hp. Am I missing something?