I have a problem with my 1964 5TA, when engine is running or off, if I select 1st gear and pull in clutch lever, the bike will not roll backwards; the kickstart mechanism engages and the kickstart locks progress backwards when it jams up against footrest. I have dismantled gearbox twice now and all the kickstart mechanism and pawl all look in perfect condition. What can be causing this lock up?
If no one here can help, there is someone on the other triumph site who rebuilds old Triumphs and documents his builds. https://triumphmotorcycleforum.com/
1964 was the first year that the kickstart shaft had internal roller bearing for the layshaft, it's normally this that causes your problem.