Triumph Repair: tr 250 carb, allen screw, float chamber

Question
I am running a 1968 tr 250 with a rebuilt motor. All stock but my tail pipe is black and sometimes overloads with too rich a mixture . Are there external adjustments I can make on the carbs? Thanks Paul

Answer
Hi Paul,
The mixture is in under the top cap on each carb. Use a long 3mm Allen down in the bottom of the oil. Some were plugged back then but if you find the Allen screw it is open and can be adjusted. Counter clockwise leans the mixture. However, there are other things on that carb setup that are more common to make one run rich and that is the choke system. Look at the choke cable to see if it is a dual cable going to a choke unit on the left side of each carb and check to see that both are closing all the way off when the choke cable is pushed all the way in. Also pull the hose off of the vapor ports on the float chamber vent ports and see if any fuel comes out of the ports when running which would be a flooding carb and a float needle and seat would then need correcting.
let me know what you find.
Howard