I am looking at pipes for a 2004 yfz 450. I am wondering which makes the most hp. Also does the sparks or ct pipe stick out past the grab bar? Is the stock grab bar on the yfz stirdy or does it bend like the raptors? What is better to do, run with a lid or no lid on the air box? Also if i run with no lid do i have to get an adaptor and outerwear and if i run with lid alls i have to get is a replacement filter right? I searched and didnt find info that i needed.

 

I have a Fat Boy 4 complete system on my 04 YFZ i have not had any problems with it at all. Right away when i put it on i had a noticeable gain in throttle response (but i cut 4 coils of my carb spring) and in power wise. I run with no air box with a K&N air filter with no prefilter/outerwear. i clean it about every month depending on how much i ride. I normally rid ein sand drag racing

GOOD LUCK PURCHESING A PIPE!

 

I have an 05 raptor that im getting work done to. I already have a curtis sparks pipe and k&n air filter. Im gettin stage two hot cams and a 11 to 1 piston......am i going to see a big difference? Thanks

 

Cubby, Yes you should see a great amout of bottom end gain along with a noticeable amout of gains threw the powerband up to top end speed. An aftermarket CDI box would go great with your set up also