I just bought an 04 yfz450 yesterday with AC nerf bars and thats it. Its real clean and in good shape with grip still on the original tires. I am going to buy a Curtis Sparks Exhaust with the big core kit, jet kit and a K&n. What all is the big core kit? What is the difference from stock?

 

Congrats, on the new quad. I am waiting to find a good deal on one. LOL

 

Also I have a question about the air intake setup on the yfz450. If I am going to run without an airbox lid do I have to buy the adapter and the airfilter? Then I will have to drill holes and mount the lil bracket and then the thing will slide in and all that kinda stuff, like the raptor? Please help

 

Yes you do have to buy an adapter. i would get one with a foam filter not K&N, for more protection. i dont think you have to do any drilling i dont remember, but if you do its nothing serious. its a great mod with the pipe

 

if i remeber correctly the big core kit is just a bigger silencer on the pipe. it lets mor air flow through and gives your more power. its probably a little louder though. i was debating in geting this or the CT pipe and chose the CT.

 

The big core kit has a bigger outlet diameter, and is very loud. If you are getting an intake like the Pro Design, you will have to do a little drilling, nothing serious. I am pretty sure the standard K&N can be put on with no modification though.