bettyswolloks
Scooter Rider
Today Was Tomorrow Yesterday
Posts: 59 
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Post by bettyswolloks on Mar 9, 2018 14:24:41 GMT
Hello all. I'm sure this will have been covered but I can't find it so....
My carbs are coming off this weekend. When I come to balance them up what's do I do with the yics? Leave it as is and balance them as that's how it's going to be running. Or block them off and balance? Last option seems alien to me as I will be opening up an airway after they've been balanced, won't I?
Anyone know how to build a yics tool for my XJ900s?
Thanx!
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Post by crickleymal on Mar 9, 2018 15:35:57 GMT
What are yics?
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Post by spike240 on Mar 9, 2018 21:41:51 GMT
Thought it was me. I haven't got a clue either. I heard of yics on the first xj's. Still don't know what it stands for.
Btw - why are taking carbs off?
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Post by spike240 on Mar 9, 2018 21:50:19 GMT
YICS stands for the Yamaha Induction Control System and is a performance and fuel-efficiency-enhancing cylinder head design that promotes better and more complete combustion chamber "filling" and "mixing", and thus better combustion efficiency via a cast-in, full-length, 10mm diameter chamber within the back top edge of the cylinder jugs connected to special passageways within the cylinder head. This chamber is sealed with a small hex-headed bolt ("plug") and sealing washer at each end, and within the chamber has 4 individual tiny holes (or "sub-intake ports", as Yamaha calls them) that lead up into the cylinder head's main intake passageway.
YICS made it's first appearance on various 1981 models, and was used until 1986.
"Just googled it"
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Post by Beehill on Mar 10, 2018 7:55:13 GMT
, and was used until 1986. "Just googled it" So that would mean they are not in the XJ900S??? Andy |
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Post by spike240 on Mar 10, 2018 8:25:40 GMT
Just re-read first post. Wonder if he means the exhaust valve thingy on the D9.
If it is, it can be removed or left on. Makes no difference to running of the engine, but if you take it off, it gives a bit more room under fairing, plus gets rid of a bit of weight.
Atb
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bettyswolloks
Scooter Rider
Today Was Tomorrow Yesterday
Posts: 59
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Post by bettyswolloks on Mar 10, 2018 18:15:56 GMT
Thanx all. I actually meant yics as in the induction stuff. I thought I couldn't see it on the bike! LoL! The last yam I worked was a n XJ650 Turbo, which was a nightmare to balance up due to the yics nonsense. The carbs are off, been scrubbed on the outside, they're just trying off in the fire place as I type!  |
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bettyswolloks
Scooter Rider
Today Was Tomorrow Yesterday
Posts: 59
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Post by bettyswolloks on Mar 13, 2018 17:12:44 GMT
Fitted and balanced, my goodness what i difference! I could hear it smooth out as I was turning the screws, done many in my day but this has been the one that's made the biggest difference! Can't wait too go to work tomorrow Lol!!
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