I know it’s not an enduro, but I bet I can get best answer here from the amazing experts. My R5C and DS7 rock, if you love enduros I highly recommend for added fun. I am looking for a clever way to synch carb throttle position at idle.  I synchronize WOT with my fingers and the adjusters on the caps so both slides hit WO at same time. I got air screw perfect to go with pilot jet that I bumped up from 30 to 35 because it was definitely way too lean.  It idles really nice at 1000 but I have no idea how close the throttles are at idle.  Can’t get a snail on it like my bug.  So I eyeballed them as even and then tried to adjust same.  question - is there a clever way to synch throttles at idle without taking boots off, which is a hassle?

I'd say you have it sussed so just carry on & don't worry. If you had two vacuum gauges you could plug them onto the oil line fittings & starve it of oil for a minute--or premix. Vacuum doesn't account for faulty mixture etc but does account for low compression on one side--or both sides. Low on one side & you end up with 'that' slide up a bit compared to good full comp side. Think what i used to do is back off the stops so slides hit the bottom, then turn speed screws in to 'just' feel the slides touching the speed screw. Then turn screw in say half a turn on both carbs so you know they're both the same. That shouls be about an idle. Then take up the cable free play at each carb so minimal play. Then you know they're lifting together & topping out the same. If idle is too slow then go in an even amount maybe 1/4 turn.
Umm--not sure where i'm going with this haha, so i'll slink back in the corner. Carry on i think you have things sorted well. Miss my R5 i had in the "70's, 'crash job i tendered for & won'. Easy fix but nowdays i doubt straightening the fork tubes as much as mine were bent would be legal. Think front guard was just about back between the exhaust headers lol. Color was a deep orangy red by memory although we did sell a purple one new at work.

Thanks RT
i actually “Think what i used to do is back off the stops so slides hit the bottom, then turn speed screws in to 'just' feel the slides touching the speed screw. ” before I installed the carbs.  But my short term memory sucks and I might have got L and R tweaks out of synch.   I think I need to buy a new bike 

One thing I do with synchronising twin carbs . With the carbs off the bike , and with the slides in place .
If you look into the venturi from the motor end , you can match the small clearance under the leading edge
of the slide on both carbs . Then I refit into the intake manifold rubbers , level the carbs and then with a mirror placed
behind , open the throttle until the trailing edge of the slides almost clears the venturi , and adjust cable adjusters
so they are identical . Then refit carb to airbox rubbers .
You still might have to fine tune idle screws evenly , and then fine tune air screws for pilot circuit .
It's a bit of mucking around , but worth the effort .




 

The old twin snowmobile carbs.. with them off(I know it’s not what you wanted to do) back the idle screw so the slides bottomed out.. open the throttle and place an 1/8” drill bit, the shank end, the slide is holding the drill bit, tip the carb so the it’s vertical start threading the idle screw until the drill bit falls out…
Sneezles61