Setting idle mixture

[81xsproject]

I a non-specific Google search for setting idle mixtures. I got a lot of hits for auto/hot rod tuning. I read through a few and many suggested hooking the intake manifold up to a vacuum gauge and that the best mixture setting would yeild the highest vacuum pressure in the manifold.

Is this a method we could theoretically use on our bikes????

There are obviously some major differences in function, particularly that one adjustment screw is changing the mixture that is shared by ALL the cylinders instead of just one.

It just seems like there has GOT to be a way to adjust the mixture besides voodoo magic, dynos, and wide-band O2 sensors... And don't say Colortune, that thing is worthless as far as I am concerned (have tried it several times and every one it will only ignite the cylinder about every 5-8th revolution)

[randy]

When I do my synchro, I use a separate tach hooked to either the gray or orange at the TCI and after the synch, I'll turn the idle down as low as the engine will tolerate. Then i'll tweak the idle mixture on each carb for the highest rpm's. then it''s back to the synch one last time. smooth as silk.

[Jeremy_Sells]

I have used Colortune on numerous bikes and cars with great and accurate success! If you are experiencing a flash every few revs, then your setting is too lean. Try backing out the screw until you reach the threshold of blue flame turning to yellow flame. The transition will happen very quick. Turn the screw back and fourth until you find the exact spot that it goes from blue to yellow or vice/versa and then screw it in (lean) one full turn. You should see a nice blue flame that is sparking every time! Viola - perfect mix and smooth idle. If your needles have ever been screwed it too hard over the years, you may find that the number of turns from seated will vary greatly from carb to carb, but the colortune will ensure that they are all set the same. If you really hate the colortune, I'll take it - I could always use a spare!

[81xsproject]

I really want to use it. I payed like $60 bucks for the damn thing. It seem like having the spark gap recessed so far up in the whole is a bad design. I will give it another shot just for you