Welcome to the forum The.Rick, yes the sizes referred to are Mikuni, yes the baffle is actually the screen that keeps all of your packing from blowing right out. All of that packing does help keep the noise dwon but it's also for performance as it guides all of the exhaust through and out of the cannister instead of it just starting to tumble around once it exits the midpipe.
I would keep it in there, and keep the cannister packed tight.

 

Thanks very much for clearing that up. I will be keeping the baffle in and buying a few jets in different sizes and see what happens.

Thanks again!

 

I haven't rejetted yet but got the tip on and just did a quick ride up and down the street. I have to say the sound is way better. Not too loud, but a much nicer sound and deep growl. I don't know if it's the fact that I haven't been on the quad that much over the winter or what, but by adding the K&N and the tip sure seems to make a HUGE difference in throttle response. Have a Big Gun rev box on the way and still have to play with jetting when I can get out of the city to test things out. So far I'm sure glad I bought the tip instead getting a slip on.

On a side note I noticed that the stock can has the USFS Spark arrestor approval stamped right on it. Now I know that was with the original tip, but I'm wondering if a warden would actually give you a ticket seeing as how the new tip does have a screen in it and the pipe is stamped and if you didn't know better the tip could be stock??? Anyone ever been stopped and checked?