plugging the yics

[soccer4m]

Been seeing an interest in people wanting to plug up the p.i.t.a. yics system. Has anyone come up with a way without pulling the head? Maybe a long shaft the same size as the hole, and the right diameter to slide in? I know some members, have pulled the head but I have a fear of screwing something up that way,,,,I have an Xj1100 and an xj550 with the yics. Both Yics are a pita to get the carbs synched perfect. So,,,any working ideas without pulling the head and plugging the holes are more than welcome to all. Mike in Sun Diego

[FJ111200]

But ain't a long shaft the same size of the hole and the right diameter to slide in, the YICS tool anyway? Once you've got that, ain't the problem of carb balancing sorted?

[Rhumba]

Do a search for YICS tool. You can make one from common hardware.

Try this link

http://www.xs11.com/forum/showthread...=&threadid=436

[soccer4m]

yics tool

I think leaving in the YICS tool would cut off some of the air flow passages along with the YICS ports. Also, the Homemade tool has rubber parts that would fry inside the engine. I was thinking a solid rod of some kind????? Anyone have ideas that could work to have something inserted permanently to cut off the YICS and still allow airflow to all the other nonport areas???? Mike

[madmax-im]

Its been done before

Hey Mike...I'm sure more than a few here have done this.Personally I have not...but if you do a search I'm sure you'll find plenty on this..

[soccer4m]

maybe its possible

Hi Madmax,,,,,I wish someone had done it without pulling the head, but I searched the archives and nada. SO, anyone know how to do it without pulling the head let us YICS people know how to do it????? Mike

[trbig]

It would be fairly permanent since cleaning it out later would be a major PITA, but get a big tube of silicone and a caulking gun and a clear plastic hose that will reach the back (Right side) of the YICS tube, and fill it up as you back the hose out slowly. The silicone will withstand the temps the back of your head gets. The actual YICS port is a tiny opening right in front of the intake valve seat. I don't think there would be any way to force that silicone all the way into the head to mess with that, but it might get up into the head a bit and make it tough to disassemble the head from the cylinders at a later date.

This blocks the tube that interconnects your ports in the head to each other and would let them be individualized that way. If you did much searching, you may have found where I plugged mine with the head off. At a later date, I could open these ports back up... but it would be for a nitrous installation, not to let the YICS become operable again. Maybe someday when I hit the lottery... course I have to buy a ticket first, right??

Tod

[Ivan]

I only semi-sorta-kinda know what YICS is. Can someone elaborate on what this is and how it works (or is supposed to work)?

[trbig]

The YICS (Yamaha Induction Control System) consists of a tube attached to the cylinders that run along the back side of the motor with four holes that align with holes in the head...




Here's the head upside down..





If you look into one of these holes in the head, there is an orifice at the top that leads to a hole directly in front of the intake valve seat.




This is (I assume) to help equalize the carbs for a longer period. You could have one fairly bad adjusted carb being helped out and drawing from the others. It was to help pass emissions at the time. That's why you have to use a tool to plug off this passage, so you know you are adjusting a particular carb.

I tapped and threaded the ports in the head and installed some allen head plugs with teflon tape. (Shown with the black arrow) I also have some '78 cylinders on the bike, so there's no YICS tube to mate to these openings.. leaving them somewhat exposed past the fins for some future experimentation maybe!! *Evil grin...




Tod

[Yahman]

Re: maybe its possible

Originally posted by soccer4m
Hi Madmax,,,,,I wish someone had done it without pulling the head, but I searched the archives and nada. SO, anyone know how to do it without pulling the head let us YICS people know how to do it????? Mike

I was thinking about this the other day... The YICS port seems to be machined in such a way, that you could just insert a steel or aluminum rod that is the right diameter to be a close fit. It would be installed with the engine hot, then just put the cap bolt back in place. It might not want to come back out in the future though.

Larry

[Yahman]

After measuring the port on my XJ it would appear to be a 10mm bore, that would be the max diameter for the rod. A 25/64" drill fits snugly (.003" to spare) when the motor is cold. Take a 10mm aluminum rod cut to the right length and put it in the freezer. Bring the motor up to operating temperature and insert the rod into the port. Once the temps have equalized it would be almost permanent.

Larry

[soccer4m]

somebody try it

Hope somebody tries the silicon injection or the rod insertion and let us know how it works. Maybe one of them is an easy fix for the Yics, Mike

[Ivan]

Wouldn't that be the same as connecting all four vacuum ports with a few hoses and Ts?

[Yahman]

Wouldn't that be the same as connecting all four vacuum ports with a few hoses and Ts?

Almost the same but not quite.



Well in my pile of odd and ends I found a guide rod from a printer or a scanner (note sure which one) that is just under 10mm (.392") and it will just barely slide into the YICS port with the engine cold. I will first need to clean the port out real good.



It looks like the port length is about 14 3/8 inches. I will drill and tap the end of the rod so that it can hopefuly be removed again with a slide hammer.

This would give me a way to plug, tune, syncronize and most importantly get a good plug reading. Then when it is right I can return the YICS system to its normal function. It would be a nice way to compare the difference between having the system working and when it is plugged.

Wish me luck...
Larry

[soccer4m]

YAHMAN can do it!

Hey Yahman,,,,hope this works for you with the plug insertion. Let us know the results and long term report. WHat type of metal are you using? The same as the head, Aluminum? Maybe you could report on the synch before and after the plug and YICS tool to see if they match......All us YICS owners are waiting and hoping it works,,,,maybe You can start a YICS insertion tool business if it works well,,,,,,,,regards, Mike