Triumph Repair: tr-6 carb troubles, vent tube, tr 6

Question
What, or how do you lean a set of 175cd's on a 76 tr-6. It runns great on the road, but it seems that it is too rich at idle. I have tried to adjust the needle with very little luck. any suggestions would be great.  Thanks

Answer
Hi John,
Remove the top of each carb and with your 3mm Allen wrench confirm that the needle does move up and down and confirm that the needle was in the lower position. If it is in the lower position on both carbs, inspect the diaphragms and reinstall the pistons. Confirm that the oil in the top is not heavier than engine oil.
Next look the choke assemblies and tell me which kind you have. Manual or coolant operated. If it is manual, confirm that both are fully closed when the cables are in the off position. The trimmer screws on the side and the thermo trimmer are not able to make one run rich.
Other things to look at are the carb vent tube or high float level.
Let me know what you find.
Howard