Quick YICS Removal question...

[CdnDave77]

I've been meaning to remove the YICS chamber on my 83 before it becomes a problem. I bought some caps to plug the ports with, but got reined-in very quickly when I tried to get a good look at the inner YICS cylinder ports : the outer hoses are no issue, but I can't even see the inner ones.

 

So my question is this : is it possible to remove the YICS hoses & cap off the ports without having to pull the whole carb rack ? It looks way too tight in there for my hands. I do have a 4-yr old, but she isn't all that handy with a pair of pliers (yet).

 

Just wondering...

[5bikes]

If you can't get the cap on the nipple coming out of the intake port, cap off the hose. Use a bolt and hose clamp.

I just super glued the seam on the YICS chamber when I had the bike all apart doing the 2nd gear fix. And kept it. I get 45-50 mpg, thinking the YICS works. Later 1300's don't get as good of mpg without it.

[Sheradan]

What problems does the YICS chamber get??

[Venturous Randy]

What problems does the YICS chamber get??

 

The chamber can crack and the hoses get rotten. Any leaks tend to be major ones and cause sync problems.

RandyA

[Dano]

Dave, use a long pair of needle nose pliers to get in there and install your caps. Use the same clip rings to hold them on. Works for me!

 

Dan

[CdnDave77]

I'm not sure it is a problem... yet. But it is kind of a Just-In-Case. I may do an experiment & pull the chamber but plug the hoses themselves as 5Bikes suggested. That way, I can give it a good once-over, reseal the chamber and pop it back in. I'll see if I can document any mileage difference.

 

Thanks fellas.

[ScottXD45]

What is the Yics supposed to do and what do I plug off to get rid of it? Anyone have any good pictures?

[CdnDave77]

Well, the YICS is the Yamaha Induction Chamber System, which (and I'll hold off on the engineering lingo) basically is another chamber attached to your intake ports (between the carbs and the cylinder bank) that holds some additional air-fuel mixture and lets it flow into the cylinders at a different angle from the main air-fuel intake. This is supposed (and does) give a better combustion, and therefore better mileage/fuel economy, etc.

 

It was a fantastic idea on the inline 4-cylinder engines (Maxims/Secas, FJ's)... a simple port could be cast in the head - no additional components, no moving parts, nothing to wear out. However, Yamaha marketing decided it needed to be on the V-4's as well. The geometry of the engine isn't naturally suited to a single interconnecting port on all 4 cylinders, so the design engineers had to add an external chamber and connect it to the cylinders with individual hoses. Of course, to make it light (and cheap), they made it out of plastic which does the job fine for a few years. But 20+ years of heating/cooling cycles & vibration takes its toll and they begin to leak. The hoses suffer the same fate. Eventually, the device that was supposed to improve the performance of your engine begins to erode it, making your engine run lean as the leaks increase.

 

I also think the YICS chambers make the engine a little more robust initially... and by that I mean the carbs need less attention. But, if you are willing to learn a little bit, and give your bike a good check-up occasionally, the bike will run just as good without it. Maybe better, depending on the condition of your YICS chamber.

 

Removal isn't hard, but to completely remove the hoses, I had to pull the carb rack off the intakes to get at the inner ones. All you need are vacuum caps to cover the YICS ports on the cylinder banks (I re-used the hose clips). Remember to do a re-synch of your carbs ! Mine was much different than with the YICS.

 

My bike runs better without it, but my mileage didn't improve much - I get 36-38 mpg, but I am betting it is an issue with throttle application on the rider's part, not the engine.

 

The YICS have gone the way of the Dodo bird now... replaced by fuel injection systems that eliminate a lot of hassle (hint, hint Yamaha).

 

Hope that semi-explains it. If you need pictures, send me a PM and I'll try to email some after I get home tonight.