Syncing or Sinking

Made my yics tool last fri and tried to do the carb sync yesterday. I made the Norman Kokes version1.3 that is posted in many places only I used 8-32 instead of 6-32. Just seemed more substantial. I guess it is correct although it don't make sence to me. Looks like it should have four seals for four carbs. Anyway it seemed to work marginal at best. put it in the left side as per instructions and 1-2 were easily balanced. Connected to 3-4 and nothing doing. Then I thought switch sides with the tool and then 3-4 balanced easily. connected to 2-3 for the center adjuster and these were much harder to balance. Very slow responce time. I used the 2bottle rig I made with atf in it . The atf damps nicely. After completion I saw no difference in idle. Prone to wander up and down and I can't let all the way off the enrichner or it dies even if I turn up the throttle stop. Must be sucking air so where :cry:. May be the throttle shaft seals since I used blk rtv for the carb joints.

 

Use an unlit propane torch to probe for vacuum leaks.

Sounds to me like it could also be a float level issue; did you check them using the "clear tube" method, with gas?

 

If you don't use a larger rubber seal on the end of the "homemade tool" (which the drawings and instructions for the homemade tool fail to mention!), then you have a big vac leak on the side where the tool is inserted..........and you ain't "synching" at all!

 

Since you are already closely sync-ed, you can take the tubing you already have and make a "loop" or 2 tube Manometer easy enough.

If you haven't made baffle/restrictors, just jam wadded paper towel bits in the tubes near the intake manifolds. Tightly packed.
Or take the time to make the proper ones with epoxy.

Ideally, you should be using a ColorTune at the same time to make your idle mixture perfect.

 

Yes to the tubes, . 1/4" vinyl was perfect. I got them each right on the money. I was mostly suspecious of the yics tool. The way it's made according to the plans only on hole in the fwd top of the tube actually gets covered. I noticed that Koke's plan is for an 82 1100 and I have a 650. Would that make a difference or is the YICS tube casting the same for both?

 

I wondered about that Len. The passage is blocked but the threads,washer holes and rod shaft are not sealed. The way I made it was with threads on each end of a smooth shaft. Enough on one end for the nylock nut and 2 1/2" of thread on the wing nut end. When it is tightened enough to compress the 3 rubber sections you really can't tell what is happening between the shaft and the compressed gromets. I think maybe the homade rig leaves too much room for error.

 

That's the real problem right there......

 

I think one with gromets or tube sections as such should align with each YICS port that goes into the head so there is no question of a seal. I have never seen a factory tool so I am unfamiliar with their design. Do any of you know how many holes are inside the YICS tube?

 

No, the seals don't align with the port holes; they are spaced in-between the port holes (see the sketch below). The idea behind the YICS tool is not to actually seal off the port holes; rather, it's to prevent "cross-talk" from any one port to any of its neighbors.


Here, this is rude, crude, and barely acceptable, but hopefully it's understandable:


("o" = port holes)
("x" = 3 small seals)
("Y" = 1 large end seal)


chamber -> |-----o-----------o-----------------------o-----------o----------|]

tool ---------> Y______x____________x__________X________


If you're missing the large end seal "Y". you have a vac leak from outside the engine into the far left (in the diagram above) YICS port, and thus into the #1 cylinder.

 

There are 4 holes, and you could make a sync tool with just 2 bits of rubber- - one blocking the passage for #4 and one blocking #2.
The passages for #1 and 3 would "breathe" into little dead spaces.
Blocking #4 would also seal the end.

Someone suggested gluing a Schrader valve to a length of hi-temp tubing.
Insert and inflate. Done deal.

 

That would require greater precision and would only work for one configuration. By blocking the passage between the ports you have a tool that will work on more than one engine.......

BTW, the thing that has not been discussed is that the YICS passage needs to have the end plug in on the side opposite the tool.

 

Exactly....and that's why one tool will work on all 550 - 1100 engines.

TIME's idea about an "inflatable raft" that you shove into the entire passage has some merit, too.........

 

i don't want to start no shnit here but i know what i'd do with that YICS tool

 

Thanks guys. I have the picture now.