Slowly sorting out my 72 Triumph. When I start it cold and go to kick it into 1st gear it grinds and stalls out the bike. This happens with every start for at least 5 or 6 times until it finally goes into gear and then it shifts smoothly the rest of the time I'm riding it. Even after turning it of and starting again. But if I don't start it for a day or so it fights going into first on startup again. It shift fine into 1st gear when the bike is off. Any ideas whats causing this and how to resolve it?