Intruders-Alert

You can do it by ear, you can also use an inductive tach on the plug wire.
Advance Auto has free tool rental.

I was wrong, I have a couple more questions.

I'm looking at a set of instructions that are very straight-forward, but a couple questions occur..

Instructions found under: viewtopic.php?f=10&t=12231 (4th reply)

It recommends that I observe the butterfly valves opening simultaneously, but they're in the units, do I need to take the boots off or can I observe the axle that's sticking through the cable bracket?

Also, is the sync cable referenced in the butterfly valve instruction the same as the idle sync cable in instruction 4 under "now sync"?

Sorry to be dumb but I haven't done this before and I'm having trouble finding a set of pictures that do the process justice, the shop manual photos are trash.

For the butterflys,
I stand on the right side of the bike, left hand on the front carb external butterfly linkage, right hand on throttle while watching the rear linkage.
Slowly crank the throttle
You should feel the front start to move when you see the rear start to move.
IF they aren't close, adjust with the sync cable.
This is a rough adjustment.

The fine adjustment is done with the SAME sync cable using the vacuum gages.
Sync cable adjustment is very fine, small movement changes vacuum alot.
Use Sync cable for idle speed and throttle cable adjustment for high speed.