YICS tool question

[mlew]

I have been having problems for a while getting my XJ11 to idle well. I have been through the carbs and cleaned and replaced all the guts. I then built the YICS tool to the measurments in the diagrams I found. After several attempts to sync the carbs it wasn't any better. I made another attempt yesterday , but still the same. All the intake pressures read the same and still a bad idle. I held the YICS tool to the head of a spare engine and noticed that the tool will not seal the passage between # 3 and 4 cylinders. Could this be the cause of my sync problems. I modified the tool length to seal each passage and tried again. WOW what a difference, nice and smooth idle now. Has anybody else had the same problem with their XJ11 while using the YICS tool built from the plans? Is this tool supost to work on all YICS engines? Or are they specific to each enging size?

[trbig]

Things like this is why I plugged off the YICS ports in my head. You could have one fairly bad carb, and the rest would be picking up the work for you with slight decreases in performance over time.

I bought all the stuff to make one of these tools, but never actually had to use it since I did the above mentioned mod. I'm glad you got it figured out.

Tod

[mlew]

Can you plug the ports without taking the engine apart? Tell me how you did it. This is the only YICS bike I have, I have never had any problems with the other XS11, they don't have the YICS.

[heatmanal]

I've had the same problem. what mods did you make? did you make the rubber pieces longer?

[Ken Talbot]

Originally posted by mlew
Can you plug the ports without taking the engine apart?

Sorry, no. With the head off, you can tap the gallery holes and seal them off with some screws.

[mlew]

Thanks Ken
I may tackle that if I ever have to take the engine apart. with only 16k miles I hope it will be a long time.

Hey heatmanal
Build the YICS tool just like the drawings shows, but change the two 4 1/4 " tubes to 4" and 6". Put the 6" piece at the end that goes in the head first. That should seal off all the passages. It worked for me.
Good luck.
Mark

[DELL82]

I had a similar problem and altered the YICS tool to match my port dimensions. using a stiff wire with a small bend in the end I could measure when the bend fell into a port.
I have a theory that because the factory plugged the idle screws they had a way to adjust individual carbs for their particular flow rates, that done they plugged the screws. However the carbs still needed sync, so the YICS tool was created.
From my perspective the color tune would be done without the YICS tool installed. That done the YICS tools is then inserted for sync.
WHAT SAY YOU GURU'S
dELL82

[trbig]

Doing a colortune without the YICS tool installed would be no different than trying to synch the carbs without it. You could get a good reading on the colortune, but could actually have a cylinder running really rich or lean and depending/drawing air from another cylinder to make up for it.

The YICS is kind of a crutch. It helps a cylinder lean on the others when it isn't doing too well. Spread this help out over 3 other cylinders, and one can get pretty crummy before you realize it.

Any tuning on any of the cylinders would require you to individualize it with the YICS tool.

Of course... I've been known to be wrong!


Tod

[DELL82]

Thanks Tod, guess my thinking was in err

[trbig]

LOL.. Not necessarily. Like I said... I've been known to be wrong a lot. I don't know this for a fact... just the way it would seem to me.




Tod

[heatmanal]

thanks mlew I did the same thing you did cleaned & recleaned the carbs still idle'd bad. I'll try your mod. this weekend.

[DELL82]

heatmanal and mlew, Have you guys checked the boots on the carbs, the ones between the carb and engine? Could be one or more are leaking. Use an engine starter, either, or UNLIT propane torch and spray around the boots while idling. If engine starts to run higher there is a leak. fix by cleaning very well with acetone or and alcohol then paint with black RTV using an acid brush. Worked on mine and helps keep the boots from UV light.
Jeff Covington found at the NTCC that the little boots on the vacuum ports, on the same carb boots above, were hard and leaking. Replaced with Auto Zone vacuum caps, whistle and leak went away.
Dell82

[mlew]

Hey Dell82
I replaced my intake boots last year because they leaked, put on new caps also. I had tried silicone on them but they were to far gone.

[DELL82]

Well eliminated one more source. Keep going eventually it will come.
Dell82