Bench setting for '83 550 Seca Mikuni Idle Mixture Screws?

Ok I've searched and searched, and see lots of discussions, questions, etc. but I'm still not finding:

Following my carb overhaul, where should I start with the Idle Mixture Screws? They were all over the map, as found.

My rule of thumb for carbs is to start at 1.5 turns out from lightly seated, but I've not worked on Seca 550 carbs before.

Input?

Thanks,

Kirk

 

HOW all over the map?

I'd start at around 2.5 - 2.75 turns.

Float levels (wet) and vac sync (YICS blocked off) before further tweaking.

 

Well, they were gummed / varnished pretty bad. Not as bad as many I've worked on, but bad enough to prevent the slide from moving, and no daylight thru the jets, emulsion tube holes blocked, the usual suspects...

They ranged from 1.5 open to 6 open, but I don't believe the PO knew what he was doing. He 'claimed' he rebuilt the carbs recently, but they were gunked up enough to represent a good long while and I'm not convinced it ever ran properly for him.

It was a non-runner when I got it, of course.

Yep, that's the drill - float level setting, syncing with YICS blocked, etc.

Anyway, start at 2.5 ~ 2.75? Thanks. That's further open than I'm used to on vintage Honda/Kawasaki/Suzukis, so I'd've been quite a bit off. And everything I can find only says "preset, keep your meddling fingers off" or words to that effect...

Kirk

 

Be sure the motor is GOOD and warmed up before you start doing any ColorTuning or mixture adjusting. The inner two cylinders get warm before the outer two do, enough to throw it off if the motor isn't fully warmed up.

You may end up in at 1.75~2 turns but better to start off a bit fat and come back.