this was here few times before but there are few new member now and maybe someone is interested how to fit and wire electronic tacho to carbed america or speedmaster.....
managed to get cheap drag specialty black face tach like this one

but its apply for one of those

too
tacho has 4 wires; green, black ,red ,blue...under dashboard on your tank you got 3 sockets for clock(3 pin),alarm(2 pin) and triumph tach (2 pin)
black from tach to brown for clock
green from tach to red for triumph tach
red and blue from tach to red for clock
when you connect this new drag tach to system it does this
tach and here how it works
tach