Vacuum ports

["Richard Chawes2"]

Thanks all for the help. It turns out it is simple to do. The carbs have the correct hole already in the side and it goes almost all the way down to the pilot air passage.
All you have to do is with a tiny drill (like #57) poke through the last mm or so.
If you remove the pilot screw you can see daylight right through.
The port is 6mm for the hose but steps up to 7mm for the press fit into the hole.
Some locktite will probably help.
Got some on order from Hermy’s senior (610 562 3155), not the son who runs the BMW/Triumph dealer.

Richard Chawes

["Dennis Grossman"]

Now that we have had a good discussion regarding vacuum ports, I would like
to know the favorite and most effective tool for tuning and balancing the
cylinders.
Denny
75SS

["Robert Fleischer dba Fleischer's Service"]

IMO, adjusting the carbs and throttle cables is most accurately done by the shorting method. The other methods are various ways of measuring or comparing, the signal at the vacuum takeoff ports; and, one method of measuring the incoming air flow to the carburetors. Most folks have a favorite method.
I like the shorting method, as it costs little to nothing, and is very accurate. That method….AND OTHERS….are fully discussed, here:
https://bmwmotorcycletech.info/synchcarbs.htm


The method I most dislike hearing about is adapted from the method BMW promoted for the PRE-/5 models….well, perhaps better said, the magneto models…in which the spark plug caps are removed and re-connected, back and forth. It's not at all safe for the later models (/5 onwards) that have coils, but no safety gaps….and, is not all that accurate, either.

Snowbum