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My $10 DIY YICS Solution

Started by skatefrench, August 19, 2016, 12:39:27 AM

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skatefrench

Hey! I tried sealing my YICS 3 or 4 times, then finally gave up. I rode with it plugged up for a while, then decided to build my own. I initially was going to use copper pipe and solder the ends on, then tap in some barbed hose fittings. I actually ended up discarding that idea because the box store didn't have large enough diameter pipe to make it work.

I ended up buying 4 PVC end caps a 1 ft section of 1 1/4" PVC, and 2 threaded hose barbs. I took the existing YICS, poured water into the 2 chambers til each one was full (I had my YICS split in half, but this would probably work better with it all in one piece). I then poured that into a measuring device. I used that to calculate how much volume each new chamber should use. I think it was right around 100-102 ML, but I don't remember for sure. One chamber is slightly larger than the other.

I cut the pipe, glued one end onto it, then drilled and tapped a hole for the threaded barb fitting. I installed the barb fitting with JB weld to add an extra seal. I then put the 2nd end cap on and poured the quantity of water I had measured from the original YICS into the chamber through the hose barb. I adjusted the fit of the end cap til I had the volume of the container just about right. I marked a line on the pipe to indicate how far onto the pipe I should slide the end cap when I glue it. I took the unglued pipe end off, dried all the water out, then glued that end on.

As you can see from the pics, I used a pipe clamp to secure the cylinders to a piece of sheet metal. I drilled a hole in that piece of metal to secure it to the original location with a 10mm bolt.

I was a little skeptical of using PVC for something that encounters fuel. But I've had it on there for about 7 months. I just removed it to check vacuum, and both YICS chambers still hold vacuum after all that time. I was getting used to the original YICS chambers constantly leaking, so its refreshing to have one less thing to worry about.


Rikugun

Nice work and a good looking installation too. I like the look of the silver clamp and flat black chambers.

When you removed them to check for leaks did you find that some liquid fuel had collected in them?
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

skatefrench

Hey thanks! I like the looks of how it turned out, too. I painted the metal backing plate with some grey hammered metal spray paint, too. I like the look of it.

I didn't find any liquid fuel when I took apart the original yics. I just meant that it encounters fuel in the sense that it's part of the intake system of the bike- one challenge of trying to seal the original YICS was finding a goodles sealant that could stand up to fuel.

Rikugun

QuoteI didn't find any liquid fuel when I took apart the original yics. I just meant that it encounters fuel in the sense that it's part of the intake system of the bike- one challenge of trying to seal the original YICS was finding a goodles sealant that could stand up to fuel.

Actually I meant if you had an opportunity to remove your new YICS (not the original) after it's run for some time if you found liquid in the chambers.

The reason I asked is I have a bike where someone fashioned YICS chambers from copper tubing fitted with barbed hose outlets. I had them off recently and discovered they both had some liquid in them. It smelled of the foulest rotten gas you can imagine, times 10.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

skatefrench

Oh gotcha, that makes sense. I actually have the YICS off right now while I'm cleaning the carbs- just shook it to double check, and no liquid fuel in there. That's pretty interesting about the copper one. Looks like I dodged a bullet on that one. I wonder if the copper acts like a heat sync and condenses the fuel vapor.

Rikugun

That condensing fuel vapor theory was brought up when the copper YICS idea was floated on the forum some years ago. I don't know the bikes history so there are potentially other reasons but I'll put these back on and make a point of checking them periodically.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

pinholenz

Good job!

I notice that you ran with the YICS ports capped for some time before you built these plastic fantastic chambers.

What were the main noticeable differences between running with and without YICS?

POD has installed twin Malossi Boost bottles in place of his YICS
http://ridersofvision.net/rovforum/index.php?topic=13508.400

And as a matter of interest, XZ-Ernie on the German XZ550.de forum has been building his stainless steel YICS alternatives and offering them to Forum members. I hope that his design does not have the condensing problem reported with the copper designs. However, I would have thought that a warm day and engine heat would have evaporated any accumulated fuel...
http://fivefivezero.bplaced.net/wiki/index.php?title=Datei:YICS_Edelstahl.jpg

All of which cost much more than your $10 beauties
Only one '82.5  eXtreme Zen 550

skatefrench

Those boost bottles look sweet! Love it. My PVC guys are working well still, I think one might be deforming a little bit, but can't tell for sure.

I think if I remember right, the main difference between YICS installed vs capped was easier starting with it installed. I think I actually noticed that difference between my leaky yics and it being capped. I don't remember if I noticed the same change when I installed the new one. Since I installed this new unit, I've also cleaned the carbs and coated the tank. So it's been a work in progress. I would say that the difference between plugged and YICS is pretty minimal. My guess is that it effects the mixture in some ammount, which effects cold starting, and probably gas mileage. But that's all a guess. My bike isn't perfectly tuned, it just runs adequately, so if there's a difference, it's hard to detect on my machine.

pinholenz

Given that Yamaha built their YICS out of plastic, and that POD reports that his boost bottles have an internal spring to help the bottles self adjust their capacity, I suspect that some degree of deformation is actually desirable in a functioning YICs. When I had mine installed and working, I could feel it pulsating. In fact I probably still have a mini YICs on my bike. If I was deaf I would know it was still alive by  feeling its pulse at the YICs port caps.

Looking forward to hearing about POD's experience. His boost bottles sure look the business!.
Only one '82.5  eXtreme Zen 550

Rikugun

Quote from: pinholenz on September 06, 2016, 05:33:05 PM
Given that Yamaha built their YICS out of plastic, ......I suspect that some degree of deformation is actually desirable in a functioning YICs.

I thought he might be referring to deformation from heat? Depending on how they're mounted, they may be closer to the engine and PVC may not be as tolerant to heat as the OEM material.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

skatefrench

Yeah, I think it may be deforming from heat a little bit. I have a metal shield behind them that helps. But at the spot where the hose clamp goes around the pvc it looks like it might be bending inward a little bit.

skatefrench

Just wanted to update: after 2+ years of running with these PVC YICS canisters, they still hold vacuum pressure perfectly. They have deformed significantly due to heat, maybe cause of fuel exposure? But while pulling the carbs for cleaning, I decided to vacuum test them and was pleasantly surprised that they are still holding vacuum.

Rikugun

Thanks for the update. Did any fuel collect in them?
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

skucera

Thanks for the update after two years.  I sometimes wonder how well fixes like this last.


And here's where my mind wandered, inspired by this thread....

I got pondering...  I have an odd feeling (not backed up by science) that the triangular shape of the chambers is also a factor in how YICS works on the Vision.  Yamaha has always been and remains first and foremost a company that makes musical instruments, and it seems that this acoustic engineering prowess shows up in everything Yamaha makes, starting with using pressure waves in exhaust pipes to help scavenging and cylinder filling in 2-strokes decades ago.  I wondered if the YICS boxes have their triangular shape to help with RPM range tuning, or if the triangular shape was simply a stylistic touch from the styling department.

So, I started Googling...  The descriptions in the late Seventies and early Eighties don't go into technical detail.  The ad writers kept the details especially light, and the repair manual writers didn't go into how YICS worked much more deeply, but at least they show pictures and described how to work on the systems.  Ads go into features and benefits; manuals talk about how to bypass YICS to perform maintenance, but info on troubleshooting or theory of operation.

OK, on models with V-4 engines with YICS, the "boost bottles" are hidden away out of sight and they are unremarkable squashed cubes with rounded corners and reinforcing creases and a wedge shape.  Here's one from a Venture V-4:



So, these related V-engines both used chambers, one per cylinder, but I didn't realize that the inline 4's didn't use "boost bottles," but instead just linked the intake runners of each cylinder with a cross-bore through the head.  They use pressure pulses directly so the pressure pulse from a freshly closed intake valve packs extra swirl and air/fuel mixture into another nearby port with a valve that is just opening.  These pressure pulses are at the speed of sound (acoustic in another word) and thus right up Yamaha's alley.  The acoustics of the V-engines leave awkward gaps in the cylinder filling order, so these clever Yamaha engineers used the bottles as echo chambers... acoustic delays of varying size and timing to accommodate the slightly irregular V-twin firing order.  Very clever.

Forgive me while just I geek out a bit on this realization.   :)

So, the different depth of the two ports on the must affect the pulse reflection time... the echo time... in the chamber.  I had wondered why the two sides were different, and this might explain the difference in the two ports and why the two chambers are different volumes.  The triangular shape?  That wedge shape to the chamber may affect the character of the pulse and its pressure attack and decay.  Since the Venture's YICS chambers are not so pretty, I think the triangular shape on the Vision was partly the result of artistic vision from a stylist or two, but the shape was probably dictated by engineers who set a lot of parameters for the same, run lengths, port locations, etc.

I think I'll be pondering this more later, but it's getting late, and it will soon be "crunch time" at work.

So, forgive the mental diversion away from skatefrench's canisters.  Thanks again for the update two years on.

Scott

Rikugun

Interesting perspective. Maybe you should have written the ads!
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

skucera

No, I was just a college boy when the Vision was new.  I only went into the ad business and graphic design in the late Eighties.  I made a run of it for five years, but switched to software testing, which has been both more lucrative and more fulfilling.  So, I'm the only engineer on staff at my company with two art degrees. ;)

I must admit that fluid dynamics and acoustics was not my strongest subject when taking "Physics for Architects" in college.  I much more enjoyed mechanics and electomagnetism.

I was thinking about that wedge-shaped chamber, and perhaps it is wedge-shaped for the same reasons that a megaphone flares out.?. to redirect the sound energy from running in all directions around the opening of the port to run away from the wedge.  Then if it reflected off the perpendicular end, it would reflect off the flaring sides like in a listening horn right back at the port opening.  Acoustics are a little non-intuitive for me, so it's hard to picture....

Scott

skatefrench

Sorry I don't keep up with the forum as much as I should! Haha. To answer the question from years ago above, no fuel collected in the YICS chambers I built. I'm actually preparing to sell the bike
now, as I purchased a fuel injected 2007 Suzuki V Strom. The Vision has never let me down! But I won't miss cleaning carbs  :D

injuhneer

#17
There are actually really good descriptions of YICS in the inline-4 manuals.

I posted a synopsis here:
http://ridersofvision.net/rovforum/index.php?topic=12535.0

Also offered to 3D print a YICS box to test the viability of a printed version.
- Mike O
1982 Yamaha XZ550RJ