Anyone else tried synching carbs with and w/o the YICS tool?

A few years back, I had the XJ550 sit around too long so I took it by the local mom and pop so they could get me going again.

The mechanic cleans the carbs up and gets me going after adjusting the pilot screws by "feel" and synchronizing the carbs using the 4 bank of vacuum gages. I ask him about the YICS tool and he gives me a blank stare and shows me that the carbs are all in sync and the bike runs about as good as it ever has. At that point, I am convinced there is no need for a YICS tool.

Fast forward a few years. This is about a year and half ago, and I had once again let the bike sit around for too long. This time I decide to go at it alone. I make a YICS tool and see no difference between synching with and synching without. I once again disregard the tool as unnecessary.

Fast forward yet again. Last year I bought a 2006 Ducati to make the 110 mile round trip to work when the gas prices were so high, so of course, the Maxim gets neglected again. Well, just before I bought the Ducati, I had been having trouble with the Maxim and just about three weeks ago decided to check the valve clearances and completely clean the carbs. As well as replacing some parts, I completely disassembled the carbs and rebuilt them. This time around, I swore to buy the YICS tool that chacal sells and "do it right". Well, yet again, I fail to see where the tool makes any difference at all.

After a little bit of trial and error and fixing a couple of vacuum leaks with my set of gauges, I finally get the carburetors in PERFECT synch. Here is the thing. They are now in synch whether I use the YICS tool or not. It doesn't matter if I use my homemade jobby, the tool chacal sells, or nothing at all. There is no difference in the vacuum readings. So what gives?

Has anyone else experienced this? Is it perhaps that the YICS system is more effective on the larger bikes, and hardly makes a difference on the 550? I don't mean the tool makes a little difference. There is no difference at all. All the gauges run exactly the same with and without the tool. They flutter the same. They equalize in the same spot. They run up and down together.

 

I didnt use it on mine and mine are dialed in damn nicely
I dont know if I would say perfect, but they are on target

 

Re: Anyone else tried synching carbs with and w/o the YICS t

My brother worked for a dealership when he bought the Seca 550 I now own. He claimed the dealership techs had the tool but never used it...on ANY of the synchs they did, claiming it unnecessary. When I bought my Seca from him, he synched the carbs for me after I'd rebuilt them, sans tool, again, stating it was unnecessary. When I finally bought my own mercury sticks, I synched my carbs twice without the tool...no adjustments needed. Once I built the tool, I was quite upset to find the synch off as much as 3 cm between carbs. Moral of the story? Use the tool. It can't hurt, and it might help. You might check your manifolds for leaks, and check to see if your YICS passage is clogged with carbon, while you're at it.

 

Re: Anyone else tried synching carbs with and w/o the YICS t

I really don't think you can have as perfect a synch as I am currently indicating if my manifolds are leaking. And I am sure they are not as there is absoluetly no change in rpm with propane or any type of flammable fluids. I can see cracks in my manifolds, but none of them extend to the inner sides.

And I also checked my YICS passages because one of the rubber pieces of the YICS tool seems to have broken off so I had to try and clean that out of the passage. I would say that I melted it in there, but of the piece that is left behind on the tool shows absolutley no sign of having melted. The rubber seal is quite clearly sheared. Granted I don't know where the other piece went, so I guess that melted and got evaporated in the engine, but there was very little sign of it in the passage. I cleaned it with a shotgun cleaning kit. The passage looks brand new and none of the opening looked clogged as far as I could see.

 

Because of all the flap and fuss I tried it both ways last time; I found that the carbs APPEARED sync'ed without the tool, but when the tool was deployed I discovered that I had one that was quite a ways off and being compensated for by the others (via the YICS.)

I can say THIS: Once you've sync'ed them with the tool and then check without it, they will still be synchronized. GETTING them sync'ed without the tool takes a lot more time and you may never get it 100%. With the tool in place, it's a lot easier to get them right, and with minimal fuss and frustration.

YICS actually has MORE of an effect on the 550s, our passages are quite large compared to the bigger displacement bikes.

 

Re: Anyone else tried synching carbs with and w/o the YICS t

I've heard applying oil to the tool will keep it from sticking but you certainly don't want to leave it in the bike for too long. Marvel mystery oil? Regular oil? Cooking spray? Any recommendations?

 

motor oil.

 

Never heard of a YICS tool until I came to this forum. My BIL went through my carbs without anything and when I finally put them on a set of gauges they were spot on. He's an HD Certified mechanic but called a couple of his Buddy's from a Metric Shop and asked if they used gauges and was told NO, none of us use them anymore.

 

Re: Anyone else tried synching carbs with and w/o the YICS t

The seals on my home-brewed tool are made from silicone tubing rated to +500 degrees F. They won't melt. I usually give them a squirt of silicone spray before I use the tool. If yours is a commercial too, (factory, Chacal, etc) I wouldn't be too concerned; they use a high temp tubing as well. If you have a home-brewed tool, simply replace the fuel line you're using with high temp silicone, available through McMaster-Carr, I believe. If anyone needs me to hunt down the vendor, I can, just PM me. (It's been a few years since I ordered it)

 

i hate to say i told ya but i told ya

 

Without the tool, all the passages are connected to each other, and will appear to read level across the carb sync tool used.

Once each passageway has been isolated from each other, correct vacuum readings will be possible for each carburetor.

As for sticking YICS tools, Don't go riding too long with it in next time..

 

i must admit i'm curious about the tool.for the last year and a half
i used a gauge. this last time they "looked" dead on
but the bike felt off. i saw the post on a home made bottle system.
for a total of $5.00 i put them on the bike and saw the carbs were actualy
way off. now the bike runs better then ever, never using a yics tool.
so know i have to wonder if the yics tool will make it run even better?
such confusion. :lol:

 

Umm, no. When I tried it without the tool, the carbs did not appear to be synchronized until I actually synchronized them. If what you are saying is true, the system would always balance itself out and we would never need to synchronize the carbs at all. To be honest with you, I think that is what the engineers at Yamaha originally envisioned the system to be like and it was an utter failure.

And I don't believe anyone claimed to be riding around with their YICS tool installed.

 

since the yics passage does share vacuum between the carbs, at first glance you have to wonder that if you issolate each carb, than sync,then open the yics passage,then does'nt the sudden sharing of vacuum change what the original pressure was while the tool was inserted?

thx ron

 

Not sure of the exact engineering or mechanical type reason, but I would say no. Or at least only negligibly so. The reason being, once your carbs are synced, you can take a reading with or without the tool and they will be spot on and exactly the same across the board.

 

then perhaps you were right about yamaha engineers lol.

 

My belief, is that if you sync with the tool, and they are balanced, then they won't need to compensate for each other, so they will look balanced without the tool.

Once the carbs start getting "janky," YICS kicks in and keeps everything balanced until you clean again, thus keeping the performance curve more linear.

Syncing without the tool proves my point exactly. YICS is doing the dynamic balancing.

Use the tool, Yamaha engineers developed it for a reason.

I ride a 1980 XS11 Special that does not have YICS, and I can definitely tell when the carbs are getting "janky" and have to clean and resync much more often than a YICS bike.

 

Re: Anyone else tried synching carbs with and w/o the YICS t

this is the hole that you actually block off on a 750 (3/32) thats a 1/8 drill bit
how much could it really do
i hear 550's are bigger

 

Nice closeup of the YICS runner! Good detail! Thanks!

Look at the size of the hole in a pilot jet.

Little bigger than a hair strand and look at all the problems it can cause if it gets plugged, or if it's too big.

 

That is a completely different mechanical concept. I can't even believe you threw that into the mix.

 

Makes you wonder how every other bike manufacturer, and even every other model of Yamaha outside of those three or four years that YICS was used, have made due without the YICS system.

 

Wasn't interested in a pissing contest. You win, OK?

I know what works for me.

 

i seem to remember reading that the yics gallery was designed to assist
during idle...at the first millisecond or two on throttle up...and therefore
have little to do with performance after that. so if your bike runs perfect at idle, and smooth during throttle twist, it all seems moot.

any thoughts??

thx ron

 

Re: Anyone else tried synching carbs with and w/o the YICS t

Good point. Although WHY YICS was actually introduced may have been a little bit different than why Yamaha SAID they did it.

I believe the REAL reason was part of their quest for cleaner (leaner) burning engines without sacrificing performance as a result.

Making the YICS ports smaller would increase the velocity of air flowing through them; how much of an effect they really had is a topic for discussion. I would say the best comparison would be the 650 motor; was the YICS version any quicker/stronger/faster than the original non-YICS version? Was there any significant performance difference between the original 650 and the YICS 650?

 

Where did Chacal's post go?

 

Re: Anyone else tried synching carbs with and w/o the YICS t

take a look here for what this topic should turn into, a, i tried it and this is what i found, type of thing, like Fitz did
it only takes a few minutes once your setup then you can approach all the theories and know what works best for you because you did it