This has been a problem with many Triumphs, TBA, Speedys, and Triumph have not got a permanent solution. (shame on them.)
Mine went after 1500km from new and they had no real solution for this, just said some bikes do it some dont. after a few loud words and some pestering they replaced my cush drive rubbers with the T,Bird rubbers also and has been ok since, now at 15500km . still get some clonking into gear but that seems normal for a Trumpy.
you might want to insist on the T,Bird cush drive rubbers being fitted instead.
Good luck
Herb
