Not so. My 1641 had no balance pipe and once the throttles were synch'd she ran just fine and then after tuning the jets and emulsion tubes she sang even better and never gave me any issues.It will run like a dog without one and be difficult to tune.
Usually the manifolds come already drilled and tapped ready for a half inch tube fitting to be fitted.
Interesting - thanks.for the OP - yes the balance pipe will help but if you use a flow gauge to set the idle screw and idle mixture then by ear it should run great
Thanks - I spent some time last night looking at looking at some motorbike forums as carb balance pipes are discussed in great detail on them.With a pair of ICTs I can imagine that the length of the balance pipe is both preset and probably too long for any great influence.
Yup, disconnect both throttle linkages once she's running so you can set the carbs properly and then connect each link in turn whilst re-checking the flows stay the same. You'd be surprised how much being slightly the wrong length will change the throttle plates position.Interesting - thanks.
I already have the snail gauge from setting up the HPMX's on the van, so would balance this way.