Formula - before investing in throttle bodies which you probably don't need:

Remove the linkage from the outer carbs; but leave the carbs in place. Wire the throttles closed. Some of the aftermarket progressive linkage is really good at leaving one or the other outer carb cracked open.

My guess is this will clean up the idle.

If the idle clears up, add linkage to one carburetor at a time, to determine which is the guilty party.

If removing the linkage does not clean up the idle; remove both carbs, and replace with block-off plates. Readjust the center to get a good idle. Now introduce the outers 1 at a time. The idle adjustment on the center carb SHOULD NOT CHANGE!

In the "for what its worth" category, I would highly suggest solid linkage for this set-up NOT progressive. The 97 is too small for the center to use with progressive linkage.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop