Check your ENDs

[Johnny4428]

This I discovered last night checking the electrics, timing etc. Trimming the HT leads and reconnecting, this screwed off with the cable, not much holding it!

[AshimotoK0]

Thought there was a wavy washer retainer thing that held it in. Well it's like that on  the 70's style NGK ones I have seen

[royhall]

I had the exact same thing happen on some caps that came with a Boyer Bransden ignition kit. Swapped them for NGK now but the fitting method was still the same.

[Johnny4428]

Incidentally this is an NGK cap as are all caps on my K3. Don’t know whether these are original. New on order, Dave Silvers. No other known fixings on these.