Yics blanking tools

Can someone tell me the benefit to doing this(or what it even is)...I had to split cases and redo stuff and cleaned and rebuilt carbs and gonna colortune and synch carbs...but I stumbled across someone mentioning this....thanks in advance guys!

 

All about YICS

This has been the subject of a lot of back and forth, but I have never heard someone that used it say they regretted doing so. Writeup by Chacal, purveyor of not only the best parts for your XJ, but also vast arcane XJ knowledge.

 

Thank you

 

I'm about to build my very own blanking tool and manometer this weekend, its kind of exciting

 

I used mercury sticks and gauges but the Morgan Carbtune Pro http://www.carbtune.com at US$102 delivered works great for me. I use it to adjust each low speed jet then to synch all 4.

 

Yics block off tool is unnecessary. If you haven't bought or built one yet, don't bother. You can get a good tune without it.

 

I use a (homemade) YICS blanking tool each and every time I adjust or synch cabs see http://www.xjbikes.com/forums/threads/yikes-all-about-the-yics-system.14757/


Everyone has his or her own way. “We report you decide”

 

You did now

 

You had a negative experience with it? I can understand people saying it isn't worth bothering, but I hadn't seen anywhere that it hurt the process. What trouble did it cause?

 

It syncs right on with it in, took it out and the idle went to he'll. Put it back in and the sync and idle were right on. Took it out resync without it, tossed it in the can and never looked back

 

One of the problems with using the tool is getting the damned thing back out. Even with lubrication and high-temp silicone seals the seals can stick to the main YICS passage.

The work-around (if you really want to block the YICS for synch) is to use an old t-shirt, cut it into 1" wide strips, and knot the strips together so the knots end up being between the head ports when installed. Soak the "fabric tool" in automatic transmission fluid, stuff it into the passage using a tamping tool (a dowell or rod), and synch away.

RickComatic has a more etailed post if you want to search for it.

 

Good to know Polock and k-moe. I don't have any experience with either method myself, but I will be trying soon. I will try with blocking the ports off first and go from there. Just have to finish cleaning the carbs; I finally got the pilot fuel jet I was working on for over a week out, so hopefully I can get that all finished up.

 

assuming we want to ensure working YICS, what's a good way to ensure the small passages are clear? I assume ones for cyl 2 and 3 are a bit hard to reach?

 

Remove the YICS Plug Bolt out on each Left and Right side of the YICS chamber (XJ1100 only have Plug Bolt on Left side) With a flashlight you should now be able to see thru one side to the other side. Take your gun cleaning kit and using the wire brush dip it in solvent and push it thru from one side to the other, repeat until clean. Then use a patch dipped in solvent and push it thru, repeat until clean. This does not clean all passages but is the best you can do with out tearing down the engine.

 

Chacal sells a special pick for cleaning the ports and a good brush to clean the bore. You can also use a gun bore brush to clean the bore.

For what it's worth I didn't find that the ports required cleaning when I used the pick on my 750.

 

The small passages on mine had a bare dusting of carbon on them (inspected when I had the head off to swap out a broken case). Remember, they are constantly being flushed with solvent (atomized gasoline) during use.

 

Here's my idea on the subject. You are changing the configuration of the engine. You are tuning your bike to this configuration. Then you are changing the configuration back and expecting it to still be in tune. To me it makes more sense to tune it the way you plan to run it.

 

Individual experience aside, Those who designed the engine and YICS say to use the blanking tool when syncing the carbs. It does sound counter-intuitive to me as well. They talk about the idle speed being lower since when the YICS blanking tool is inserted, the idle drops a little. Perhaps this is from lower efficiency without YICS?
Just thought about this a little more. Syncing is best when the cylinders/carbs are isolated which is what the YICS blanking tool does. The YICS passage links all of the intake runners in some small way, which means making changes to individual carb settings (during syncing) is a little harder. Notice the tool is then removed before setting idle speed. That's because this is an overall setting, not isolated to an individual carburetor.

 

+1, Syncing means that all 4 should be ecual after it's done, how can you do that with all 4 linked together?

 

+2 Syncing can be done without the YICS tool but it's just not as accurate since the YICS passages help make up for an out-of-sync carb(s). Whether you want to use the tool or not depends on how accurate you want to get and if that accuracy is worth the extra step of using the YICS tool. Without the YICS tool, changes to one carb affects all of them to some degree.

 

Gentelmen, this is a discussion that has gone on for at least 20 years. Synching with the YICS passages blocked is ideal, but not necessary.
Synch without. If it's not smooth enough for you, then synch with the tool.
You are discussing what is literally a flea's-hair difference in the results.
I firmly believe that the only time when the tool is necessary is when an emissions test must be passed.
Keep in mind that we (the consumer) aren't supposed to even look at, let alone adjust the idle mixture screws.
Some of the tune-up procedures were in there to prevent the uninformed from mucking things up and having that fall back into Yamaha's lap.

 

Just wondering... I didn't sync at all and it runs perfectly smooth anyway.

 

And yet I still find it entertaining. Grin.

 

I've only been on here for a few weeks... Kinda late to the party!

 

try it yourself and report back

 

As a (semi) related tangential question: If someone was going to convert their YCIS engined bike to EFI (not saying I'm going to, or if it is worth it etc, that conversation is for a different time) do you think you would have to permanently block the YCIS passage for the EFI (assuming multiple throttle bodies) to function properly?
Thoughts?

 

FI ? how about nitrous oxide ? and use the enrichment circuit for the extra fuel ? yeeha

 

I don't think it'd matter one way or the other. Since the other injectors won't be firing unless their cylinder is on the intake stroke, you'll effectively be bypassing the system anyway.
You'll still be drawing some air in to the working cylinder via the YICS ports, so you should get the swirl effect, and you'll be tuning the injector to the total air volume coming in, so no worries about not "borrowing" fuel from the other injectors.