YICS

Before you jump down my throat, think this through.
The YICS engine runs without having a YICS tool inserted, so why use the tool when syncing the carbs, surely you would want to sync the carbs with the head in it's normal configuration.
I am not alone in thinking this.
Comments? (I'm sure)

 

Troublemaker.............

 

I can see both sides of the coin for synch'ing but for coloutuning?

 

It's probably possible to synch without the YICS tool, but it would probably also take a lot more time. Reason is that, without the blanking tool in, adjusting one carburetor would affect the vacuum draw of its cylinder, but also of the other cylinders to a lesser extent, so there'd be a lot more back and forth to get everything balanced.

 

i have a non yics 650 maxim and a yics 750 seca i use a 4tube mercury sync stick and i do not use a yics tool both bikes run great

if you can use the stick style gauges instead of the dial style your life will go much easier

 

Maybe, but the end result would be a better reflection of the engine's overall performance.

 

It DOES take a lot more time and back-n-forth. The reason for the tool is to isolate each cylinder from the others only for the purpose of adjusting. Without the tool, your reading on any given cylinder is actually a reading of that cylinder PLUS the rest of the YICS system. It's easier to adjust if you're just looking at that cylinder without any outside (and possibly still mis-adjusted) influences.

Once you're all adjusted, there's no harm in doing a reading with the tool out; as you said this is a reflection of the overall performance. And it's kinda fun; but adjustment with the tool is more precise.

 

Back to Basics 101:

What is the meaning of the word "synchronization" as it applies to Yamaha 4-stroke, in-line, 4-cylinder air pumps?

Some-where, over the rainbow,
There's an answer waiting, for you.....

 

All sucking the same, so why adjust them in isolation?

 

Having the WHAT "sucking all the same"?

 

The synchronization adjusts the setting of each carburetor's throttle butterfly valve so that the fuel / air mixture passed by each carburetor results in an equal load placed on each of the cylinders. 8)

 

i tried it with and without, without works better for me. don't take my word for it though, try it yourself

 

Support is building.

 

May be a pyrrhic victory of sorts..............

Well, that's correct in a very round-about, circuitous manner, although the phrase "load placed on" may be a bit mis-leading.


Can we try this instead:

* "Synchronization" means equalizing the power output/contribution of each cylinder so that they are all equal.

* Since many different factors contribute to, interact, and thus result in the determination of any single individual cylinder's power output (for example: piston/ring/cylinder wall interactions of each individual cylinder; intake and exhaust valve face/seat condition, valve clearance/lift/timing of each individual cylinder, carb fuel/air mixture supply----ratio and amount----of each cylinder, etc.), but we have no way of adjusting or compensating for many of those individual component factors (besides valve clearance adjustment), then the only user-manageable procedure available to adjust the power output, by cylinder, is via manipulaton of the throttle shaft/butterfly valve openings on each individual carb, thus slightly increasing or decreasing fuel volume to each cylinder.

* Cylinder power output is measured via the strength of the vacuum signal that a cylinder produces.

* Vaccum signal strength is measured via a vacuum gauge, technical name mamometer, street name synch gauge or "sticks".


All in favor, say "aye"..................

 

O bolliks :?

 

I synched my carbs last week, but this time I didn't use the YICS tool. It seems to make NO difference with or without for me. I don't think the YICS passage makes a big difference while idling anyways. My bike runs like a cat on fire and idles smooth.

 

Whazzamatta Wiz, is it raining in Oz and the Kawi's almost done so you had nothing better to do?

Gentlemen; We have another debate here that is one of science vs. opinion; but bigger than that, once again, looms the true question:

Do you really think you're smart enough to out-engineer Yamaha?

If you believe you are, then go for it.

If like me, you have found through experience that it's very difficult to out-engineer the legion of engineers that designed these things, you'll accept the need to do it their way.

 

A technical term I'm not completely familiar with......... 8O

 

Trial and Error. I guess you should try with and without. Might as well see if it makes a difference at all.
I'm going to try without today, and pick up a tool in a couple weeks and I'll post my findings.
This is all very interesting
-SLKid

 

OK ya, didn't need to out-smart the Yamaha engineers here. Just wanted to make the bike run a bit smoother and not using the YICS tool seemed to work better for me this time.
So go ahead and use the tool if you'f like. I don't give a rats ass one way or another.

 

'Without' seems to make more sense but I'd be the last to question those engineers. Still, this guy has had 6 XJs over the years and shares Wizard's point of view.

Are bikes tuned differently in the southern hemisphere? Water drains from a sink differently down there, no?

 

It is impossible to argue a contrary point of veiw with someone who has an inherent, vested interest, resulting in dogma.

 

No, the sun is still shining, (maybe not from any orifice of mine, though.)
What you have to take into account is, why the engineers developed the YICS, it was to try to produce a cleaner burning engine to meet with the, then new emissions controls, the results were arguably mediocre.
If one was to be cynical, you could say that is was a marketing ploy, an attention grabber for the "tree huggers" of the early eighties.

 

Could be.

Or perhaps it's hard to fool Mother Nature, or Father Physics.


IF----and we'd have to agree on definitions first and foremost, or we simply will continue to degenrate in the realm of "opinion" (and like other orifice's, everyone's got at least one or two of them)----if the definition of "synchronization" means:


1) an equal power output or equal power contribution from each cylinder


Then tell me, slowly and exactly, how you would measure this equallness except via the vacuum signal from each individual cylinder?


And, if that indeed IS the definition of synchronization, then how can an individual cylinder vacuum signal be measured when there is a wide open passage that connects each intake port to all others, and whose sole purpose in life is to SHARE vacuum signals between all the cylinders?



2) Now, if that is not the definition of synchronization, then tell me what is:

Sounds like cynical dogma, perhaps?

 

Don't clean the carbon out of your YICS passage and don't worriy about it. The XJ1100J (36000 miles ) I was working on today was plugged so I guess its like a non YICS engine now. synced right up . The only thing I can say is with totaly rebuilt carbs it runs GREAT. Too bad about my 2nd gear though but in 3rd she pulls real hard.

 

It runs as a 4 cylinder UNIT not 4 individual cylinders.

 

A unit is the sum of its component parts though.........

What is the purpose of "synchronization" if it doesn't apply to the INDIVIDUAL cylinders?

Why even "synchronize", then? Even non-YICS engines are supposed to be synchronized, correct?

Via measuring the strength of the vacuum signal from each INDIVIDUAL cylinder?

And then twiddling screws and mashing buttons and standing on your head while juggling BB's with your toes and consulting your OUIJA board to determine how to proceed?

Or by adjusting butterfly shaft openings on INDIVIDUAL carbs so that the VACUUM SIGNAL from each INDIVIDUAL cylinder which measures the theoretical POWER OUTPUT from each INDIVIDUAL CYLINDER is equal to all the others......thus resulting in "synchronized cylinder outputs", and thus a "synchronized entire unit"?


And how can the above be done when there is a big vacuum LEAK between all the cylinders?

 

I understand.

 

You know what would be REALLY interesting? If someone were to take a YICS head apart, take it somewhere and get the YICS passages welded up and the ports ground smooth again, NOT doing any extra "porting and polishing" and just SEE if it really makes any difference, performance-wise. Wiz may very well be right in that it was more marketing device than engineering breakthrough; but the simple bloody fact of the matter is it exists. And it really IS exactly what Len finally described it as: a massive vacuum LEAK between all the cylinders. All the more reason to plug it off for tuning, at least for vacuum synchronization.

Which raises this question: Since using the Colortune is the final mixture adjustment phase, shouldn't the YICS be unplugged because the cylinder in question will be drawing its mix from the other 3 also once in service? Remember Yamaha never intended for us to be fiddling with the mixture screws so they don't tell us anything about that part of the procedure. When they used the EGA did they use the YICS tool too? Or is it only for vacuum sync?

 

That is a wonderful question. The 1981 Yamaha Technical Training manual is pretty silent on that issue, except for two passages.

The first one deals with "Tuning For Gas Mileage", and the procedure reads:

"With the machine properly tuned, run the (EGA) idle check. Adjust the mixture screw until CO for each cylinder is approximately 1/2% less than the recommended specification. Be sure to pay attention to engine speed and carburetor synchronization. They must be constant during all adjustments."

They then go on to caution that such a setting---for improved fuel mileage---should yield increased gas mileage with "no hesitation coming off idle", but, that such a change will require "longer choking during cold starts".

It should be noted that elsewhere in the manual, they note that a low CO reading at idle is symptomatic of a lean engine condition.....and above, they are basically telling you to shoot for a Low CO reading, meaning they are telling you to purposefully lean the idle mixture setting.


The only other place that, again, indirectly mentions the issue at hand is in the table/chart of Idle CO/HC Specifications by model, by year. Under the 1981 XJ550R/RH listing, in the HC column for this bike (and this bike only; there is no listing for the XJ750RH model, for some reason.....), the specification called for is 500ppm max HC, with an asterisk noted, and the asterisk note reads:

*With YICS Shutoff Tool


Since synchronization requires the use of the YICS blanking tool, and the CO/HC measurements on the 550 model specify the use of the YICS tool, and the mixture screw changes and measurements require carb synchronization to be "constant during adjustments", then my vote is that they expected the service tech to keep the YICS tool installed and activated within the YICS passage during idle mixture screw adjustments.......akin to adjustments made via a Colortune plug in today's world.

 

Another downside of the YICS port is, if there is an air leak in one boot, say, then all 4 jugs will be effected, leaned out.
It has to be said that Yam' engineers would have to advocate the use of the tool, or they would be admitting that the YICS port is doing nada.

 

Ok gentlemen I,m a newbe to the YICS motor but it seems to me that if you sync the carbs with the tool it would be way off when you pull it out. Due to the fact that you now have a four port vacuum leak. Has any one check the carb sync without the tool after sync with the tool. My experience in syncing two or more carbs on a car if you introduce a vacuum leak into the system it screws up the sync between the carbs. It only makes sence to me if we run the bikes without the tool in it then it should be sync'd without it. I may be wrong?????

 

I could see how its working at High Speed. That would make sense. The port would make sure no bit of mixture is lost. But at Idle, it cant really compress anything, there isnt a whole lot for it to do! Since my bottles didnt work I'm going to Elec sync without, and weeks down the road I'm buy the tool and do it with.

 

The all-important asterisk! I think that one asterisk makes it a pretty DIRECT mention; they're giving us the EGA specs and telling us the tool is in use to obtain them.

YICS tool for Colortuning it is.

Wiz raises a good point about Yamaha advocating use of the tool to give credence to the effectiveness of YICS; but I honestly don't think Yamaha would have gone to all that trouble just to foist snake oil on us. I think they sincerely believed in it, and I think it did its job or they wouldn't have clung to the technology for as long as they did.

The irony in all of this is the fact that we are doing our level best to UNDO Yamaha's actual intent with YICS, to make the motors run lean (and therefore cleaner.) They wanted them on the ragged edge of too lean, we're striving for nice and fat rich blue flame.

What do you want to bet that a motor tuned using Yamaha's EGA specs would NOT burn "bunsen blue" if you checked it with a Colortune?

 

You know, I read somewhere (and darned if I didn't copy it or save a link, or if I did, I don't know where!) that, of course, the reason that we in the USA didn't get the XJ750-X (water-cooled 5-valve engines) was because of the "Harley" tariff, to protect their bigger engined bikes form "illegal and opportunistic dumping" by the foreign (meaning: Japanese) manufacturers of large-displacement bikes into the US market....which was supposedly killing HD (and HD was on the verge of bankruptcy at about that time). So as a "Buy American!" political favor, a tariff was issued, and the rest is history.....

But the interesting note was this: in that era, before HD got its "cult status", most bikers realized what was REALLY wrong with HD: their products were old, dated, over-priced, etc. Their engine technology and performance was at least 1-1/2 generations behind that of any foreign manufacturers, especially Yamaha; they were clinging desperately to the old pushrod engine design that was state of the art back in...what? the 1940's?. In fact, it was claimed that Harley engineering actually took apart some of the Yamaha engines to study, and concluded that Yamaha had perfected a method of mass-producing what amounted to basically blueprinted, almost race-ready engines for street use (obviously something the buying public had also figured out a while back).

So, although those Yamaha engineers may have been too slick and clever and cunning and deceptive to properly design a YICS system, maybe it was because they were just too busy pumping out advanced race-like engines for street bikes instead?

 

I never said YICS wasn't "properly designed" I'm just agreeing with the possibility that it wasn't the engineering marvel it was touted to be, but more of a way to "band-aid" for tighter emission specs.

It obviously WORKS; but what difference does it REALLY have? Performance alone? The jury is out.
A cleaner-burning motor? QUITE PROBABLY.
A cleaner burning motor that didn't have to sacrifice performance to that end? **bingo**

Oh, and Harley's basic (original) design dates to around 1907. I'll bet a lot of folks aren't aware where the "potato-potato" exhaust note comes from:
"Original" Harleys' (not the V-rod) cylinders have a COMMON crankPIN, the connecting rods share it, one is "forked" on the end and the other fits in between the legs of the fork. So the cylinders have to go "bang-bang--wheeze-wheeze" instead of "bang-wheeze-bang-wheeze."
Which explains why they have such a low redline.

 

Yes, the old single-pin crank design is also used on may Yamahas, Hondas and Kawasakis now. It gives that "potato-potato" sound that most like (me included) which I don't get from my dual-pin crank on my 1100 Shadow Spirit. The 1100 Ace has the single-pin crank, but makes less power, so there is a price to pay for sound I guess.
Makes you wonder why Harley never tried the dual pin crank design and got more horses/rpms out of their motors? Just a thought.

 

From my reading of the Yamaha literature on the YICS system, it was designed as a FUEL-SAVING measure rather than as a performance enhancement or emission-control system (although, of course, all three issues are inter-related). The marketing guys pump the "10% greater fuel economy without any other changes" while the engineering types ramble on about the volumetric efficiencies that accrue from swirling fluids creating better cylinder filling and better burn rates (all of which, by the way, I feel is absolutely correct, true, and a pretty basic, accepted tenet of combustion system design).

Motorcycle magazine test reviews from that era seem to verify that, as they comment on the addition of the YICS system, noting that it adds almost no performance benefit but does increase fuel economy by a measurable amount AND reduces or virtually eliminates the off-idle transitory "stumble" that seemed to be a feature of the pre-YICS engines (which might explain why the pre-YICS people recommend tying together all four intakes with rubber tubing and t-fittings on the intake manifold vacuum ports, in effect creating a simplistic version of one feature of the YICS system).

The non-YICS guys modify their engines to mimic a YICS design; the YICS guys weld-shut their YICS passages to eliminate it.

What is the world coming to?

 

Hey now, I'm not advocating welding up YICS passages, I just wondered WHAT it would do?

Come to think of it, my Norton has a "balance tube." It's a piece of tubing connecting ports (just like the XJs vacuum ports) on top of the intake manifolds to each other. Primitive "NICS?" I do believe it is...

D; I believe Harley DID shed the common crankpin in favor of more HP, don't they call it the V-Rod?

 

Welding the passage closed just to see the effect seems a bit uneccessarily extreme. Why not just do a dyno run with and without the blanking tool installed? That will at least tell you about the performance, and potentially, depending on whether you're checking 5-gas, the emissions effects.

 

here ya go Wiz link

 

Thanks Polock, it just goes to show that there is nothing new in Heaven or earth.
BTW. I notice that R.Co. didn't get involved this time around.
Have a nice day, folks.

 

Rickcomatic is to busy out riding on his perfectly tuned XJ (which he tuned using the YICS tool) to come in here and make arguments he and many others have already made.

I plan on making and using a YICS tool to tune my carbs. I've been riding for a while and my bike feels pretty well tuned. I would be ecstatic if I could really feel an improvement after tuning my carbs properly.

 

So these same "Yamaha mechanics" that people advise other owners to NOT take their bikes to for service, and who admit that they "never use the YICS tools" (i.e. never follows factory procedures) are now the fonts of wisdom and the Holy Grail, standard-bearers of AND THE BASIS OF THE RECOMMENDATIONS THAT WE ARE GOING TO SITE, GIVE, AND URGE ONTO OWNERS WHO ARE JUST GETTING STARTED IN THIS WHOLE CARB "CLEANING", TUNING, REBUILDING ETC. PROCESS?

You know, Wiz, after some thought, I'll give to you that you ARE right.....I do have an agenda. Not the one that you imply----that I'm just a huckster trying to foist useless parts onto people needlessly.....but more along the following lines:

Except for instances where the factory or aftermarket manuals are clearly incorrect...the mis-labeled air jets in the Haynes manual, for instance......I always recommend to people TO FOLLOW THE FACTORY RECOMMENDATIONS AS CLOSE TO THE LETTER AS POSSIBLE.

Why?

Because few, if any, people EVER "get it wrong" by following such procedures. Sure, in certain cases, there maybe "tricks of the trade" or shortcuts that might save a truly experienced, mechanically-savvy person such as yourself and a few others on this website some steps, time, money. But the vast majority of people who are in the first steps of learning how to work on these rather complicated, sensitive fuel systems, I feel that the exact WRONG way to go about teaching them is to say "oh, just ignore that step and kinda skip over that step and you don't really need to pay any attention to that, etc."

That just muddles up people's understanding of things, especially someone who is trying to get their feet wet on these issues.

You portray yourself as an expert---which I have no doubt that you ARE----but what's your goal here? To pound your chest and proclaim your expertise to everyone else? Is that how you truly "help others"? Especially the vast number of inexperienced, beginners that are members or visitors here?

My goal is to provide people with the correct parts and as much correct knowledge----foolproof, bulletproof, do-it-this-way and you can be certain that you won't get it wrong-----as possible. That's how you assist people that aren't technical, 20-years experienced mechanics to get things right the first time around. The 20-year experienced people:

A) don't really need your advice, and....

B) are set enough in their own ways that for the most part, they aren't going to use your advice, anyway.


I'm still waiting for an explanation of what the word "synchronization" means, as it applies to engines, and why having a big old honking vacuum leak within your YICS passage makes no difference to that synch procedure.

Because as soon as you state that a big vacuum leak does make a difference, then I'll ask you again why the Yamaha engineers made up all this stuff about using a vacuum block-off tool in the first place.

And if you say that it makes no difference as to whether there is a vacuum leak between cylinders when doing a synch, then why bother doing a synch, at all?

 

synchronization, i look at it as adjusting the idle speed of each cylinder, correct? it opens and closes the butterfly, changing idle speed, thats all it can do
vacuum leak, there is no vacuum leak, if the vacuum cap is taken off a intake manifold it will draw atmosphere, follow me here, if a tiny carb was placed on the vacuum port, would it still be a vacuum leak, no, now it's just one cylinder with a big carb and a tiny carb
once it's past a fuel metering device (carb) it's just another source, not a leak
i think anyone who is still reading this thread owes it to himself and the forum to try it both ways and form a opinion, ya can't go wrong following the book and ya can't hurt any thing not using the tool
now go get hot

 

You totally misunderstand my motives, Len, in my first post I just ran an idea up the flagpole to see if anyone would salute.
If you read any replies I make to other posts, you will see I only try to help & explain things in simple terms.
I think you doth complain too much.

 

Plenty of others around here that 'complain too much'.
Myself included

Len very well could be the most helpful guy on this board.

My thoughts on the YICS tool... well, like Polock said, I have yet to try it either way. But my guess is that it is necessary to get the sync 'in the ballpark' and that if it was just a BIT off, you could do it without it.

Then again, think of it this way... everyones talking about it being a vac leak. But, if they were isolated as if they were their own 4 engines... and they ran great that way, the YICS passage could only help remove any discrepancies (not sure if that's the word I wanted)

Meaning, if they all run perfect seperate from each other, once the vac is allowed to be shared again - if all 4 cylinders are drawing the same 'vac'... then all the YICS port can do is help balance those minor imperfections, when the motor has a SLIGHT bit more pull on one cylinder, it is equally spread out.

The motor goes through many load changes, and like Len said there are so many things, valve faces, RPM, cylinder cleanliness, compression, etc... that can alter that 'suck'. In that case, once all cylinders run PERFECT, BY THEM SELVES... once the YICS port is released, it can only help suppress those minor differences.

That's my $0.01 cent. Because nobody here probably expects two cents from me!

 

Wizard, if I mis-understood your motives, then I stand corrected. The earlier comment regarding "It is impossible to argue a contrary point of veiw with someone who has an inherent, vested interest" raised a few eyebrows though. Might have been just a turn of phrase that I mis-interpreted.

 

Polock raised a valid point, and dpawl just expanded on it: The YICS system isn't so much a "leak" as it is a giant "damper." Instead of tiny carbs attached to the vacuum ports, we have three other full-sized carbs attached; but the system is still "closed" unless there's an actual leak.

Seems like all the more reason to use the block-off tool; it eliminates the "damping" effect and lets you get an accurate reading on the cylinder in question.

 

Bingo, Fitzy,
And y'all aren't taking into account the full spectrum of the rpm range of operation, either.
The forces at work in the YICS passages at low rpm can be vastly different than at cruising or redline rpms.
Just like RF systems changing response at different frequencies, the resonances and pressures within the YICS can be drastically different at high rpm and thus effect engine performance in ways you'll never predict with a liquid synchronization gauge at idle or slightly above.
The interactions get VERY complicated and require finite element analysis to fully understand.

here's what i propose:
1. Acquire access to a dyno capable of measuring to tenths or hundredths of hp and torque
2. Plan to do all testing in the same day.
3. Run a baseline on a candidate YICS-equipped bike (Assumed to be in a good, solid state of tune, else the carb synch).
4. close the butterflies completely, then open them back up, but each of them slightly different, visually inspected.
5. Synch them WITHOUT the YICS block off tool.
6. Put her on the dyno and record the graph from idle to redline
7. Reset the butterflies askew
8. Synch WITH YICS tool.
9. Re-run curve on dyno.
10. Compare results.

Until then, i'm going to "err" on the side of believing the Yamaha engineers did some of the analysis of the YICS port effects at all rpm and studied wave propagation, cancellation and amplification as well as standing waves and pressure mapping.
Till then, i'll use the tool.

Disclaimer: I didn't stay at a Holiday Inn Express last night, but i AM an engineer in real life.
8)

Christopher.