YICS tool

Just curious, but what exactly is a YICS tool that people say is needed to adjust the carbs. And is there a fuel/air adjustment on a 82 550 maxim? It has Mikuni carbs. I've synced my carbs beforei was just wandering what the purpose of that tool is.

 

YICS is a narrow passage in the head that interconnects the four intakes. It's supposed to work some kind of performance or emissions miracle. The YICS tool is used to block the passage when synchronizing carburetors.

Your Mikuni carburetors have a fuel screw. It's located on the top of the carburetor at the front near the enrichener valve. It might be covered by a brass plug.

 

Is the YICS tool absolutley needed to sync the carbs? Thanks for the tip on the fuel screw, i'll probably leave it alone since the bike ran awsome last year and still got 62 mpg. I was just curious since the yamaha info said "no adjustment"

 

The answer is pretty much "Yes".

When the bike is running normally, the YICS passage allows each intake port to draw a bit from the other three ports. So, if the YICS passage is not blocked off when synching, adjusting one carburetor is going to affect the vacuum levels of all the ports, not just the one it's connected to.

I suppose you could eventually get things synched without it, but it would be a much more frustrating trial and error process.

 

I think the YICS tool makes your set up more precise. Since there YICS passage interconnects the carbs it will tend to mask some minor sync issues.

Be sure to check the valve lash or syncing is a waste of time.

Yamaha put the plugs on and said "no adjustment" to keep the EPA happy. My motto is "if it ain't broke don't fix it".

 

hench why each time i came back to a carb the vacuum was different than when i had left it. I see I see. Guess i'll have to find one of those tools. Man, she should run really good this year then. lol

 

Chacal has them for $37. I believe they can also be rented somewhere.

Or, you could make your own... instructions here: http://www.crc2onlinecatalog.com/yics_tool.htm

Cheers,
Paul

 

If you use Colortune to adjust the mix, are you still need the YICS tool?

 

That diagram on the crc2 website is not fully correct. It is missing the large sealing washer that needs to be on the end of the tool where it enters the YICS chamber; otherwise, you'll have a massive air - vacuum leak on that one cylinder, and you'll never get a proper synch accomplished!


And yes, you still need the YICS port blanking tool, even when (or especially when) using a Colortune. The purpose of the port blanking tool is to segregate each cylinder from all the others (which the YICS chamber joins together by design) during synch and carb tuning procedures, so that each cylinder "stands on its own two feet" (fins?) during the tuning procedure.

 

do you use the same tool in all XJ models?

 

Yes, as long as it is a YICS-equipped engine.

 

so where can I buy a YICS tool? can someone post a link please. Chacal gave me no hits on google. Thanks,

 

Chacal sells them (cheap too) and you can make one with the plans set out in our DITY section.

 

Chacal is a forum member. PM him or see his thread a the top of the forum index

 

Ethanch, look just above your last post....thats Chacal.... :grin:

 

hehehehe Chacal the mystery man.

 

I bought my YICS tool from chacal. Works great.
Make sure to spray the YICS tool with silicone lube every time you use it.
The YICS passage will be filthy. Clean it with a rifle cleaning kit that you can purchase at your local gun supply spot.