YICS Question

[Rhumba]

I haven't had to synch my carbs yet as the bike is running very well, however I am interested in the process for when the time comes.

In reading the YICS tool how-to I noticed that the YICS was described as a passage that all 4 carbs share to increase vacuum efficiency. If the carbs are connected by this vacuum passage, wouldn't that equalize tiny differences between the carbs vacuum settings, rendering syncronization moot?

Just a thought...set me straight

[Ken Talbot]

Yeah, that's what it does, sort of. And it will try to do it when the four carbs are all at quite different settings. Imagine that you've got one butterfly open way too far compared to the others, then the YICS gallery evens out the vacuum, and hence the flow through the venturi. Now you've got an airflow through the venturi that doesn't match what what another carb would do at that same butterfly opening.

That's why you want to isolate the four carbs first, then use a vacuum sync tool to get all four butterflies exactly the same. Then you can reactivate the YICS system and let it help by smoothing out the vacuum pulses.

That's how I understand it. Anybody with some real carb knowledge want to add something more or different?

[ross]

yics tool....

hey there folks...i have seen the tool and the owner explained how it works....i think ken has it right.....but ya need the tool to sync the carbs......no other way.....ya might wanna check with the guys on the xj site.....if ya can't find it, let me know....the guy i know goes by schmeerman on here, but he seems to be very good with the xj's.....i have his # (i think) if ya need.....let me know....ross

[XSPastor]

Check out this thread.
DIY YICS tool

[ross]

hey there xspastor....don't mean to step on your bosses toes, but that is a sync tool.....a yics tool fits into the engine and has a flip lever that shuts off the ports to each carb.....btw, gave you a shout out in the "an irish perspective" thread.....hope ya like....talk 2 ya later...ross

[XSPastor]

You're absolutely right, Ross. I pasted that link in based on the title. I didn't even look at the thread which is - as you said - all about sync - not the YICS tool. This is the one I was thinking of:
do it yourself YICS tool

Thanks for pointing out the error.