The Gunson Colortune tool

Stazi wrote: Where's the cheapest place to buy one from here in the States?

Any of you guys that have one, wanna loan theirs out for a small fee?

You should snap this one up immediately, that is the cheapest I have ever seen one, by far:
Amazon

I have a mercury carb sync. Thanks. I was referring to the colortune.

No eBay APP ID and/or Cert ID defined in Kunena configurationTried that approach...just went ahead and bought one.
If you lived nearby, I'd consider renting this one, but when considering the added cost of shipping, you may as well get your own. :side:
See:

I have used the colour tune for the last thirty years i would not be with out it

I just informed Santa this is now #1 on the list. Getting rid of that slight stumble off idle is gonna be so fine.

I'll probly get shit for this but I wish when people are talking about sync the carb's they would
use the term right.

To sync a set of carb's is to set the SLIDE's at the same height
in the carb bore's not with the air/fuel screw's.
She screw's are for IDLE A/F ratio they will not sync a set of carb's.
If the mech. sync is not done BEFORE any tuning you will not get the screw's any were near even
just as OMR said his ain't close to even turn's out.

OK flame on.

let me add if you have your slide's set at 1/32, 2/32. 3/32.4/32
then you have four diff. amount's of idle air flow therefore you will not be
able to "sync" the with the screw's it will take 1/4, 2/4, 3/4,4/4 turn's of the screw's
Now I'm just using these # as a refrence.

And yes I do have a colortune and if you look that morgen say's carbtune not carbsync.

No flame here. You are absolutely correct. Syncing carbs is the adjustment of slide height to ensure the vacuum drawn through all carbs is the same. That's why a tool that compares vacuum levels is used. Adjusting the air/fuel ratio is an entirely different adjustment. Ed

Spot on regarding your feedback no doubt!

I believe for the most part usage of the term "Carb Sync" as depicted in the service manuals as Carb Synchronization of the Vacuum levels that most use. Obviously, the Colortune is not in the OEM manuals... :laugh: that refers to Air/Fuel mixtures.

The Morgan unit pretty much states the same regardless if they call it Carbtune.

Now the other little tool that has made all the pieces fall into play is the AF/R gauge.... Now were talking....

Wow, you have to have a '76 smogged? That's harsh.

That Colortune tool is definitely worth a shot, it would seem. Anything that demystifies what happens in the combustion chamber is a Good Thing.

A question on the O2 sensor: if you're only getting a composite number of all 4 cylinders, is it really that useful as a diagnostic tool? I could see the rationale on a turbo rig though, where leaning out can be... dramatic,

Yes indeed for one faulty carb and you'll see the measured change indeed...

Case in point, recently, after the 1075 build run @ a 65-75 mph run normally see ~ 13.8 - 14.3 AF/R measurement. She burped/hiccuped and I immediately let off the throttle fearing the worst (extreme LEAN condition) especially after blowing the previous engine up (piston #4 disintegrated) ... :blush:

She was running rough and noticed the was measuring ~ 20 AF/R (LEAN), Pulled the ckoke a tad to add more fuel to get home..... Found 2 choke plunger caps had busted thus increased air into the carb bodies...

Freakin polymer threaded plunger caps on these carbs, really? :blink:

Order off to SUDCO.... Replaced caps and carb re-build kits for all O-rings, float valves and float seats etc... and all better.... Purr's like a kitten and my measurements while running inform me she's just where she needs to be regarding my jetting....

These will fluctuate slightly due to time of year (AZ heat or Winter), elevations, humidity, gas (ethanol) etc...

Idle: ~ 10.5 - 11.3
Low - Mid Range ~ 13.5 - 14.3
WOT ~ 14.3 - 14.7

BTW, AZ no longer requires Motorcycle emissions....

Life is good!

It is great to have that information in real time, no doubt.

What are your thoughts on the Sudco carb rebuild kits versus the K&L ones that Z1 stocks? I'm re-doing all 4 BS34s on my J2.