Comment
The M20 collets do look odd when fitted if you are used to OHV engines. In the past the exhaust valve and seat in particular needed fairly regular attention and with the barrel in place on the cases there wasn't the benefit of gravity when it came to replacing the collets...So it was all to aid replacement in that particular circumstance..I have to admit when in short supply for OHV motors I have removed the M20 'extensions' and converted them for use in those types....Ian
email (option): Ian@wright52.plus.com