how do I set mixture .. without colortune

1982 xj650 maxim

Valves are done
Carbs are Clean balanced as close as i can (no yics tool)

ATM mixture screws are set 2.5 turns out from bottom


When she starts in the morning (not very cold) I have to still give her choke about 1/4

Sometimes I have to set the idle a little high 1500 to 2000 or she stalls.
Once warmed idle goes to 3000 and I have to readjust back down

I think the mix is close as plugs seemed OK color wise when I set it after cleaning the carbs... But now seem to be on the rich side after a few days ridding ..1 and 4 being the worst 2and 3

I would like to dial in the mixture even more ..not don't know where to start
Without a colortune

The warm vs cold idle might be vacuum leak?


Side issue I have some seepage from the drain screws.. They are as tight as I feel comfortable .. Replace?

 

With out blocking the YICS it is near impossible to properly sync the carbs (I tried and failed) Once you do get them synced here is a method that works with a non-YICS engine (not sure if it works with one)

ADJUSTING PILOT SCREWS BY EAR vs. COLORTUNE

Tuning is a bit of an interactive process at the best of times. You may have to sync first, adjust the screws, then sync again, etc. Try starting at 2.5 turns out from lightly seated:



- warm up the engine and sync the carbs with a mercury tool or vacuum gauges

- adjust the idle down to approx 700 or 800 rpm

- adjust one pilot screw out slowly while listening very carefully to the engine sound and watching the tach needle

- listen for the engine speed to pick up a bit then fall off

- if it doesn't pick up, adjust the screw slowly in, again listening for any increase in idle speed

- when you hear the increase, adjust past it a half turn or so, then come back to it again until you've got the sweet spot

- adjust the idle speed back down to your low starting point

- then work another screw, again looking for its sweet spot

- each time you get a screw adjusted, drop the idle back down

- once you've got all four screws set, resync the carbs

- take one more pass through the pilot screw adjustment for each carb, still working at 700 to 800 rpm
verify that the sync still looks good

- adjust the idle back to 1050 or so depending on your personal preference



- go for a ride!

 

The high idle can be a leak or the carbs not being synced. There are ways to block the YICS with out the tool.

One way is messy. Use strips of a rag and soak them in oil and stuff them in the YICS passage (tightly). after syncing and tuning the carbs use a dental pick and pull the rags out.

 

Use an infrared thermometer on the exhaust(only a few $'s cheaper than a colortune). I had to put a small spot of tape on each header pipe to get a reading because the thermometer didnt like the reflective surface of the chrome.
Leaner cylinders will be hotter, richer cylinders will be colder.

Oh and +1 on the vacuum leak, as the rubber boots heat up the vacuum leak fluctuates, making proper tuning impossible.