> There are some very good electronic balancers. These are easy to use and a great way to go if you have multiple twin cyl' bikes that need tuning throughout the year. 

> If you just have the one bike, maybe you wouldn't want to spend hundreds of dollars. In that case you can build a simple manometer using a yardstick, 12 feet of small ID clear hose, and some red liquid (like ATF). See THIS LINK 

Remember, your carbs need to be "balanced" at idle (using the Speed screw) AND balanced at 1800 RPM (using the cable length adjusters). 

The Harmonizer is great but sadly out of production.

I used my homemade balancer for decades.  The homemade design makes it as reliable as gravity, but it is so sensitive, it can be overly touchy. So I splurged a few years ago a bought a Digi Sync tool (thedigisync.com). It is easier to use and seems to produce good results. I’m good with it!

@wobbly Great suggestion! I'll build one of those and give it a try. Thanks!

hi After many years I have used a gauge That uses mercury, I have had it for twenty plus years. I also use a colour tune kit to set idle mixture. You can see colour of spark

I've never heard of the colour tune system. Anyone else using that?

Is the color of the spark a good indicator of proper idle mixture?

Posted by: @blake-wester

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I've never heard of the Colortune system. Anyone else using that?

Is the color of the spark a good indicator of proper idle mixture?

I worked in a shop that had one. It's a clear plastic part that takes the place of the sparkplug. You can see the ignition color to do initial mixture settings.

There are several YouTube vids if you'd like to see.

@noblenobby Which adapter do you use for it?