Author Topic: Throw Away Your YICS  (Read 11890 times)

Re-Vision

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Re: Throw Away Your YICS
« Reply #20 on: October 26, 2010, 08:15:35 PM »
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Hartless

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Re: Throw Away Your YICS
« Reply #21 on: October 26, 2010, 08:53:59 PM »
maybe  mine runs better without because i have mac exhaust. plan in doing a slip on conversion. maybe
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Lucky

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Re: Throw Away Your YICS
« Reply #22 on: October 26, 2010, 10:14:30 PM »
I have Macs on both Tourer & as of Sunday, Cafe. i haven't (& don't plan to) removed the YICS from Cafe to see how it runs without the YICS, but I know Tourer runs better...
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Hartless

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Re: Throw Away Your YICS
« Reply #23 on: October 27, 2010, 04:28:32 AM »
yea, i still havnt really worked all the kinks out of mine , im sure once everything is "perfect" it will run better with the yics
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supervision

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Re: Throw Away Your YICS
« Reply #24 on: October 30, 2010, 09:10:39 PM »
 New Yama Super Tenere Air box shows pulsing chambers of some sort
 
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Extent

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Re: Throw Away Your YICS
« Reply #25 on: October 31, 2010, 01:32:47 AM »
Those look more like hemholz resonators to me
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Raj1988

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Re: Throw Away Your YICS
« Reply #26 on: October 31, 2010, 09:14:12 AM »
my next bill will be FI .. no question abt te

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zore

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Re: Throw Away Your YICS
« Reply #27 on: October 31, 2010, 11:53:56 AM »
I wont deny that the YICS probably offers some benefit as unperceptive as it may be to me.  It just wasn't worth the hassle of trying to fix it a second time and the bike runs good enough with out it. 

I thought someone on the forum was building some.  Is this still the case?
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injuhneer

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Re: Throw Away Your YICS
« Reply #28 on: July 03, 2019, 10:14:29 AM »
I know, I know. This is an old thread. Adding some color to the subject:

YICS has been implemented on many Yamaha engines. The concept is simple. Air (gases) compress and decompress based on pressure, velocity, etc. Multi-carb bikes also benefit from balance tubes (a passage linking the intake tracts together on the engine side). Combine the two principles, tune the cavities (passages, boxes, reservoirs, etc) to charge and discharge (pulse) in response to fluctuations in the intake tract (Mazda did this by linking the intake tracts on their rotary engines) and the result is a "bounce" of the air or air/fuel mix. This bounce when ported to the intake tract produces the "swirl" (retention of fuel in suspension).

This was much simpler to do in the XJ and FJ engines because they were inline designs. I used to make YICS passage tools for the XJ crowd.
Original tool:



My prototype:



Final version:

The tool blocked the passage during carb adjustment/calibration. The passage was unblocked when the tool was removed creating a chamber for balance on the head side as well as the bouncing air/fuel charge.

To get the most out of the original YICS the carbs should be balanced with YICS blocked off then unblocked reconnected. Then the chamber can act as intended rather than just being a balance passage. It seems however that the YICS on the XZ is different in that the chambers are separate? Yeah, that makes sense.

Anyway...

One of the advantages of posting to an older thread like this: How about just 3D printing new YICS boxes? I have a printer and the materials. Might be worth a shot. I'd be willing to test the concept.

HTH!

« Last Edit: July 03, 2019, 11:52:45 PM by injuhneer »
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injuhneer
1982 Yamaha XZ550RJ
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1975 Honda ST-90 (164cc stroker)
1972 Kaw GT4R
1978 Kaw KM100
2008 KTM 450 SXF