First time sync with gauges...what do they mean?? (PICS)

My 82 650 maxim runs great (so I think)....I have a friend who had some carb sync gauges so I wanted to borrow them. I hooked them up and here is what they read:
1 and 2

3 and 4 (note, I did not hook up 3, I left the vacuum line on it)

#1

#2

#4


Again, the bike runs great. So Im not sure how to interpret these? I did NOT have the YICS port blocked. Not sure how or what to do there. Thanks guys!

 

I think you need to have the YICS port blocked for the gauges to read anything worth noting

 

Re: First time sync with gauges...what do they mean?? (PICS

The very low vacuum in cylinder #1 indicates that that butterfly is more open than the others.

In fact, #1 is doing almost all the work, it's just dragging the others along. That's also the likely reason for the overall low readings.

As you dial #1 closed the idle speed will drop. You'll need to compensate by turning the idle stop screw in.

If everything is in good shape you should end up idling at about 1100RPM pulling about 10" Hg on all 4 cylindrs.

 

Carl,
I just had a thought....it IS ok to have the #3 NOT hooked up, correct? That wouldnt affect it would it? So I need to turn the #1 air screw IN? Thanks!

 

Re: First time sync with gauges...what do they mean?? (PICS

Sorry. I was rushing earlier and screwed up. I thought #3 was #1 and didn't notice the bit about not hooking it up. Principle still applies as #1 is lowest hooked up.

They all have to be hooked up to know what's going on. All you know right now is that #1 is more open than #2, and #2 is more open than #4. You have no clue where 3 is.

 

No-3 is VITAL to getting the others all Synced.

No-3 Presents the Value to which all the other are set.
No-3 has no Sync Screw.
No-3 gets Opened and Closed by the Idle Adjustment Rod.

If you don't know how much the 3-Hole is pulling.
The Other 3 could be WAY off.

Without a TRUE Value of the 3-Hole and the YICS Port left unblocked.
You are only in the right City where the Ball Park is.
Get the Vacuum the 3-Hole is pulling.
You are in the Ball Park.
Block the YICS Passage.
You are in the Infield.
Match-4 ... to ... 3
You start walking toward the plate.
Match-1 ... to ... 2
You are close to scoring.
Match-2 ... to ... 3
You are standing at the Plate tipping your Cap.
It's outta here.
Synced.

The KEY is 3!

 

HAHAHA! Rick that was BRILLIANT! LOVE IT! I will get on that today and post more pics/results of what I find out! Thanks!

 

Re: First time sync with gauges...what do they mean?? (PICS

If you are using a "homade" YICS tool you must assure yourself that the #1 vac port is blocked or the outer seal that is missing in most drawings (ie: the one that blocks air getting in at the wingnut end) is sealed.
To correct the homemade version make the sleeve nearest the wingnut 3/16" shorter and the #1 rubber tube 3/16" longer. Doing this will block the #1 vac hole and the yics passage from outside air making the fourth outer seal unnecessary. Chacal had pointed this omission out to me and that is how I came up with this solution.