Fabricate a YICS

[Glyn Pickering]

OK - lets get rid of that brittle badly constructed plastic box with something more robust. At least that's what I thought when checked both of my boxes and both leak badly.

I'm constructing a first draft this w/end out of two small cast alloy electrical conector boxes available at our local Dick Smith (electrical suppliers). The boxes have nice strong screw down lids which should be able to be made airtight with a little gasket sealer / silicone.  One box for each pipe. Drilling the lid to take a brass hydraulic line fitting with a threaded back, to which I can screw up nice and tight to seal.
I thought as a first off I should try and mimic Yamaha's internal volume of each chamber in the YICS as close as possible. You might think they gave this a bit of $ R&D at the time. Would be quite interesting to experiment with geater/ smaller volumes over time to see if this improved things (or not). Anyone out there ever tried this construction? If not why not?? Seems an easy way around a very common problem on the site.  

Cheers

Glyn ;)

[Lucky]

It's been mentioned before that there probably was a reason they used plastic originally, due to it's ability to flex, even if only slightly, so that might be a limiting factor to using metal.  interesting to see your results

[silicon_toad2000]

I was thinking about the volumes, I reckon Yamaha would have made the volumes of the yics so that the stream of air to swirl the intake charge would last the entire time the valve is open.
So the higher the revs the lower the volume you need as the valve just isnt open that long, but the more the throttle is open the larger volume you would need as the vacuum isnt there to suck the air out of the yics.
I think going to a smaller volume would be detrimental but going to a larger volume might improve things.

I had a look at my setup, some knob took the yics off. The hoses are connected to each other. Are they better off capped?

[Lucky]

Your better off capping them off than leaving them directly connected, hooked directly together you've basicly confused the intake flow. i know someone once hooked them together and blocked the hose in the center with a steel bearing. maybe you've got that bike...

[harry_angel69]

I started to fabricate two spheres to do just those exact tests.  But I have had to place them on the winter/spring "shelf" for now.  I was starting with double volume, and I was using a sphere to try to assist with the "swirling" effect that the is supposed to occur.  Using the electrical boxes is a good idea to start, but watch out for the paint on the box.  It is was never designed to come into constant contact with fuel or that much heat.  I would consider sanding down the inside so that crap does not end up in your valves or cylinders.

I really did not figure that I would get a noticable difference in perfomance.  It seems to me that the people who plug the YICS say they notice a higher idle and a smoother idle without it, but that is a symtom of a bad YICS.  Lucky ,and the other senior members, have said many times that a properly synced and tuned bike with sealed YICS runs just like it should.  That is the other reason for the spheres.  I am going for the cool effect.

[Lead_Deficiency]

Can you not do the same job as the YICS if you connect the hoses with a "T"

Is it just to prevent fuel spit back and to even idle?

[h2olawyer]

Lead -

The YICS chamber is divided into two chambers inside.  Any attempts to connect the two cylinders will not work.  Connecting the hoses with a T would cause the same problems as when the YICS leaks internally.  (erratic idle, sluggishness & major stumbles)  The YICS is supposed to help make the fuel burn more efficiently by mixing an additional fuel/air mix charge with the primary intake charge & creating a swirl in the cylinder, leading to more complete combustion.

H2O

[Lead_Deficiency]

Do any other manufactures use something like the YICS