I'm new to dirt bikes. I've been around M/C's my whole life. Owned street bikes for a good portion of that time, mostly track/race bikes. Everytime I bought a new street bike I had to mod it out. I finally broke down and bought a 05 Wr450F and a Honda 50 for my son so we could ride together. I promised myself and my wife I would not spend any extra money on the new bike. Did the free mods and felt very good about the bike. Went to my local Yamaha dealer today for a Oil filter. It turns out a old friend is the Parts Manager. I left with a full FMF Factory 4 system anodized blue, Quiet core insert, Scotts Stabilizer, Cr High bend bars, Upper triple clamp, Grips. I can't ever walk away from a good deal. I'm an addict when it comes to M/C's, please help me! Have any of you used or looked at the FMF Factory 4 system? It was very pricey, retail for around $699.00, I paid allot less of course. But even with a large discount it still was bucks. I'm just guessing I will have to re-jet at this point. Will the J/D jet kit work for me with this set up? Will a fuel injection guy with limited knowledge on carbs be able to complete the re-jet? Sorry about all the questions jammed in the post. I have got allot of great info from this site. Thanks Guys.