JAP 2A Wico Magneto

Does anybody know the correct resistance of the secondary, high tension, winding of the Wico magneto for a JAP2A please? I have four all of which look very dubious and am trying to see if any are likely to be serviceable

I would guess that like most coils the resistance would be around 4-5000 ohms.

Many thanks. Next question what is the thread form on these engines. With the age I had assumed it would be BSF but for the head at least it does not appear to be

crabtree wrote:Many thanks.  Next question what is the thread form on these engines.  With the age I had assumed it would be BSF but for the head at least it does not appear to be

I'm not sure exactly what thread the head studs are on those, I never found anything in my collection of taps and dies that fitted them! They might even be BSP or a cycle thread? Pretty much everything else on them is BSF though. Reminds me of the early Morris engines where the head studs were metric in the block as they were based on a French design, but either bsf or bsw on the head nut end.

Pete.

Magneto
Not sure what type you have fitted, but I've just measured my Wico Series A at 5.66 k ohms

Head Studs
What diameter and thread pitch? Maybe time to splash out on a set of thread gauges and a cheap digital caliper.

Jap 2a/s head studs are of British standard cycle thread. Most other threads on jap engines are the same profile. See Tracey tools for taps and dies.

Some new JAP 2A head studs on ebay at the moment.