YICS rag doll

I've been thinking for a week about a way to improve Rick's idea of stuffing the YICS passage with oiled strips of t-shirt.

Now here is my idea:
1-take a section of rather malleable galvanized wire, three times the length of the YICS passage and fold it in two in the middle ;
2-cut short sections of t-shirt strips, maybe 2-3 inchs long (not sure for the moment) enough strips to entirely cover the length of your folded wire with overlap;
3-make a small loop by twisting two times the folded end of the wire
4-put a first strip of t-shirt between the two wires and twist the wires tight two turns
5-put another strip and do the same until you have the right length to fit in the YICS passage then twist a few turns tight end cut the balance of the wire.
Tadam! You have your YICS rag doll with a small loop to take it out easily when you're finished.

Doesn it sound to you like a good idea?

 

here's another idea, forget the whole YICS thing, turn your attention to more pressing matters and live happily ever after

 

Haha, thanks, but thinking about YICS doesn't make me feel unhappy, does it to you?

 

I cleaned the YICS passage a couple years ago...... I think that's the only time the passage was ever opened.

Dave F

 

The rag doll tool, soaked in oil, wouldn't be to clean the passage, it would be to block it while balancing the carbs.

 

i forgot about it long ago, now i'am in the, ignorance is bliss, state

 

im digging the idea, even if nobody else seems to be *shrug* going to probably employ something similar, maybe the same dont know but i like the idea. no idea how they pushed the strips in there before but this makes some sense. maybe a hanger or something idk.

 

Ricks original idea was to draw the T-shirt through with a hooked bit of wire I think. Quebecois' idea I guess is to make something a bit more permanent? :?

TBH if making stuff like that's your thing fine, personally though I'd want to use a fresh bit of rag each time looking at the crap that builds up in the passage... I use a home made YICS tool that came with the bike anyhow so all good here lol

 

Actually, it was just to make it easier to pull it out once the job is finished.

But the more I read about it, the less I'm convinced that using a YICS tool or whatever homemade replacement is useful at all.

Like a member wrote, the engine usually runs with the YICS opened so what's the point of blocking the YICS while balancing the carbs?

The only thing that it would show if the adjustments on carbs are different with or without YICS blocked is that you have one of more YICS passages plugged up by crappy deposits.

 

OK I see, would probably help clean the passage better too I guess

I suppose the point is that if one cylinder is relying on the one next to it to provide some mixture, blocking it & balancing the carbs will do one of two things

1 make engine run smoother when done, as that cyl's carb is now in sync and it no longer relies on another's mixture...

2 make engine run worse when done as the carbs need rebuilding to clear a blockage on 1 carb that required another to be out of sync to compensate for it... (or cause a complete misfire on the bad cylinder)

And crap-blocked YICS would be shown up by no difference with the tool in place (blowing my own trumpet a bit now, but I had to throw my sync out to check they weren't blocked on my bike as bench sync was spot on! )

EDIT-: I guess another thing the YICS blocking could be useful for is for a Yamaha tech. to gauge whether it's "worth his while" doing a sync, as if the YICS isn't clogged-up (unlikely when these bikes were still being serviced by them) and the engine doesn't change it's note when the tool is in then the carbs must be pretty close on.

 

You could always use a wire 410 shotgun bore cleaner.

 

Good idea, but most of Canadian (like me) don't own a shotgun, so i think it would be cheaper to use t-shirt strips than go buy a shotgun brush.

 

Maybe, actually, if #3 carb draws less vacuum then the other ones, it will clearly show on whatever balancing or sync'ing tool you use, if the YICS tool is in. Then you could do the statement that #3 carb was out of sync and make adjustments.

BUt then you remove the YICS tool and ride the bike, what happens if YICS passage to #2 carb is half blocked or totally blocked? I'd bet that your engine would act like you didn't sync #2 carb properly. This carb would rely on other carbs and on YICS chamber and other passages.

That's why I think that the YICS tool is useful for nothing but to make it obvious that some YICS passages aren't 100% clear. (Then what would coud you do about it?) If all four passages are 100% clear, I can't see how using or not using the YICS tool could make any difference.

THat's my point, but I'm opened to further explanations.

 

A "bore snake" is about 17$, they work well.
Cleaning the carbs won't help the yics passage
If you pull the carbs you can spray carb cleaner down the tiny hole to the yics port
But there's a oring in there if it gets messed up, your pulling the head

 

Further, Definitive, and Final explanation here http://xjbikes.com/Forums/viewtopic/t=14757.html

If you read (and fully digest, that's the tough bit, took me a while.) what exactly YICS is doing mixture wise you'll see what it's doing, why it does it & why the carbs should be synced to their own individual cylinder for it to work properly.

 

Actually, copied from that thread this is pretty much the "distilled version" of why you need to bother blocking the YICS off...

Right from the horses mouth as it were, if you've got a factory fresh bike with blueprinted engine and carbs exactly to spec, or an old snotter with carbon'ed up YICS, you COULD technically do without, but considering our bikes are usually somewhere in between or closer the "snotter" end then blueprint (sad but true), there's no point doing without for the sake of 5 minutes & a couple of quid/bucks in case we put holes in our pistons (they take longer than 5 minutes and cost more than a couple of quid, see.....)

 

If you use a sync tool or vacuum gauge, there's no way you could be so out of sync that it will cause a holed piston. The engine would run a bit crappy at worse.
A holed piston is mostly caused by too lean of a mixture, adjusted with mixture screws, not sync screws.
THe main concern about using YICS or not would be the top end performance,as Len pointed out, and I would add maybe fuel consumption.

 

But if

then, when the revs rise what happens, YICS hole cannot supply adequate mixture to both cyls, both lean out, both go *POP*....

And, the PILOT mixture is adjusted with the pilot screws btw, the main jet accounts for what, 95% fuel at full throttle...

 

OK, all of the fuel jets are important in the mixture depending on how much you rev the engine, but it has nothing to do with syncing, in my understanding.
If one carb relies on YICS chamber to supply most of the adequate mixture, I don't think this will lean out the other carbs. The main intake is still working on other carbs and it is pretty wide compared to the YICS passages. This will simply decrease the general performance, I guess.

 

You were asking though about why bother using a YICS tool/otherwise blocking the YICS to sync. If you do this and suddenly a cylinder drops off you know you have a problem that you otherwise may not have picked up if you hadn't blocked the passage.

I dunno, I just accept that the advice Yamaha gave when they sold the bike was that the carbs should not be synced unless the valve clearances are known correct & the YICS is disabled with the tool. You're making my brain hurt now lol

 

Well, I just wanted to bring up the point that the YICS tool seems to me more of a diagnosis tool of how clean your YICS passages are than a sync tool. It doesn't sound logical to me to sync the carbs in a way (with the YICS tool in) and run the bike in a different way (without the YICS tool).

 

remember on a 750 the passage from the runner, where the YICS tool goes, to the intake is about 3/32 or .8mm. so whatever it's doing, it isn't doing much of it.

 

Given how well the system works, not much is just the right amount. A cleaner, more complete burn, makes better power.

Think about this. How much change in orifice size does 1/4 turn of the idle mixture screw equate to?

 

Thanks for the earworm, dude...

Aerosmith - Rag Doll

 

^^ haha good stuff

 

Catchy little tune!

 

[quote="quebecois59]...It doesn't sound logical to me to sync the carbs in a way (with the YICS tool in) and run the bike in a different way (without the YICS tool).[/quote]

You block YICS to isolate the carbs from each other. Otherwise, you're not reading just the vacuum from the carb you're trying to adjust, you're reading a "combined signal" from all 4.

The single biggest reason to sync with YICS blocked is because Yamaha says it's necessary; that's good enough for me.

 

I'm curious to know where are these o-rings located exactly? Any drawing?

 

Here is the very last section of Len's explanation about YICS tool use:

« Now, to be fair-----if the bike has been reasonably well maintained and the cylinders are all fairly close to begin with, you can usually get away without blanking the YICS passage and still achieve a reasonable state of tune. At the opposite end of the maintenance spectrum, the YICS passages are often already plugged up with years worth of accumulated grunge and grime, so the bike is effectively being tuned with the YICS system disabled and the presence of the tool is irrelevant. But we have seen some examples of carbs where one cylinder was effectively relying on it's neighbors to supply most of the mixture through the YICS system, and this most certainly affects performance, especially the top end.

So, my recommendation: for an engine with approximately equal compression across the cylinders and valve clearances in spec, make sure the YICS passages are clean and use the blanking tool to tune the carbs. »

Is it just me or do the very first and the last phrases say different things?

 

No, first he says you COULD get away with not using.

Last he RECOMMENDS, as do Yamaha, as does Fitz, as do I FWIW, that you do use the tool

Dunno why I'm biting like a dumb ol' carp at your YICS baited hook, you're always going to argue your point. I think just because you're interested & struggling to fully understand the system, which I'm not knocking you for, at least your trying.
Unfortunately it's a funny thing to get your head round I guess a lot of people (myself included) don't FULLY understand why you *should* use a YICS tool and never will. Please though accept like most of the rest of us that Yamaha says use it & that should be good enough until you either know exactly why you should or should not.

And if/when that day comes, please tell me what the conclusion of your studies decides!

 

I really like to know how things work and what they are used for. JUst being told to do something because Yamaha says so is not enough for me, sorry about that. Yamaha says "use yamaha lube" for your engine oil, how many of us do so? Not a lot I guess.

But I agree that using the YICS tool in a bike you just bought and that you don't know for sure how well it has been maintained could be a good to learn more about your bike.

 

quebecois59 We could use a hockey stick!!!

 

Yamaha says use YamaLube!
Harley~Davidson says use Harley-Davidson Motor Oil

Neither Yam nor H-D are in the Oil Business.
But, both are in the "Bottle Business"

The ONLY thing "Special" about the Oil you get from a Dealership, ...
is the Bottle is comes in!

A Logo and a pretty color picture on the Bottle ain't worth the extra two or three bucks!