Lucas K1F magneto cut out

Now you have to use the kill button to change gear without closing the throttle or declutching.

A Lucas SR magneto is a much better deal than a wader. You can buy them cheap - they are fitted to many stationary engines. They are rotating magnet and the condenser is external. I have done lots of things with K2F magnetos. Even when they are rebuilt by professionals, they are unreliable.