Monday, March 07, 2005
YICS (Yamaha's Incredibly Crappy System) - So I start pulling things apart to try and find out why I am getting a back fire in the exhaust. What do I find... My YICS Box (or as some call it my YIKES Box) has a severe leak on one side and a minor leak on the other. Apparently, it is not leaking from one side to the other. In the picture, you can see how badly the one side was leaking. It looks like someone had repaired it at one time using RTV Gray or something. Now I have to see if I can repair it after it's already been repaired once before. I wonder if the hammer trick will work with the gasket seal already in there?
Paraphrased from the Yamaha service manual:"The YICS consists of 2 seperate chambers, each connected, by a hose, to a port on each cylnder just behind the intake valve. As the piston moves down on the intake stroke, the cylnder fills with a fresh air/fuel charge. A vacuum is created in the YICS chamber at the same time. When the intake valve closes, part of the charge is drawn into the YICS. When the intake valve reopens the mixture in the YICS shoots back out through an angled tube into the cylinder, mixing with and swirling the main intake charge. The swirling charge is then compressed and ignited, burning more completely and producing more power than that of a conventional engine."