tuning questions?

i have a yics tool, colortune plug, and vacuum gauges. i've read you vacuum sync first with the yics tool in place...then colortune. is that all? i've also read you vacuum sync then colortune then go back to the vacuum sync and once more on the colortune. what about colortuning at higher rpm's? sorry...i'm new to this.

 

back and forth, back and forth. Perfect tune is something approached but not necessarily reached, in math terms.
Never actually used a color tune. I hook mine up to the vac gages and the precision tach on the diagnostic cabinet.
Get vacuum sync'd then take the tool out and let it cool, replace the plugs. Now turned the idle as low as it will stay running, then fiddle with mix screws. When a cylinder is on good mix the RPM will come up. lower the master idle set, repeat with the next screw. Repeat with the whole rack.
Reinsert YICS tool and check vacuum sync again. Adjust as needed. Should be pretty well on if you've done all with a keen eye on the gages and a fine touch on the screwdriver.

The way I've always done it.
I intend to do this and confirm mix with colortune for grins.

 

Color tune only at idle!!!! You will burn it out if you try at a high idle! Color tune should be done at 1050 RPM or as close to that as possible. And its color tuns, vac sync, color tune, vac sync until you are satisfied. And make sure the vacuum caps are good when you color tune or you wont get anywhere. I had one bad one, looked and didn't show signs of leaking not even with a leak test. But as soon as I put a gear clamp on it I could set it.

 

thanks everyone. "fine touch on the screwdriver" is right militant. i botched the first attempt on the vacuum sync so badly that i took them off and bench synced again. now i'll try again. i'm assuming i should vacuum sync in the same sequence as a bench sync?

 

Vacuum sync sequence: (ASSUMING VALVES IN SPEC)

Remember #3 is "home base" its only adjuster is the main knob.

Also remember that #1 is "tied" to #2. SO:

Sync #1 to #2.

Sync #2 to #3; it will bring #1 along with it. Now #1, #2 and #3 should all be in sync.

Sync #4 to #3. Done.

Adjust main knob to set idle speed.

 

Are your valves in spec? If not that's the first step. Then what everyone else says.

 

Good point. I figured anyone who spent any amount of time reading this forum would know that by now...

Editing my response.

 

Was surprised you left it off in the first place which is why 8 added.