mods for new bike

hey guys, I just got an 09 yz450f and would like a little more power out of it soon once I get used to it.

what would you recommend I get for mods?

I am very interested in a JD jet kit, and an exhaust, but im not too sure which exhaust would give me the best performance. im leaning towards Yoshimura as ive heard good things about them. what do you guys suggest?

What do u guys think about the fmf mega bomb is it interchangable withany other brand of silencer ?

I ride lots of trails and would probably need more bottom-mid end than anything.

anything else I should know/change on the new bike? this is my first brand new bike. I have a feeling the chain is junk and gonna get replaced soon, as well as the clutch/brake levers replaced with unbreakables or hand guards.

how about a skid plate?

any info would be appreciated.


Get the suspension setup for your weight and skill level. More important than power, IMO.

I weigh about 180 pounds and dont have a clue how to set up suspension

Any suggestions

You want MORE power out of a 450? Not to be a dink, but...yes....over the internet, I can say for a fact your not ringing it out to potential. Why waste the time/money?

Swapping the exhaust out on an '08-'09 YZ450 is about all you really need to to do. The stock pipe creates a "soft spot" in the power curve in the lower mid range (4500-6000) that makes the bike feel weak at lower RPM's. Almost any good system, or even a slip-on, will improve this. DRD, Yoshimura, and FMF systems seem to be the most popular.

Another thing you can try is an '06 exhaust cam. This will clip a very small amount off the top end peak power, but gain considerably in the middle.

As far as suspension, you don't need new springs at your weight. Here's a link to a basic setup guide.

I weight 180 and ride gncc and hare scrambles. On my o8 I am running a fmf with the power bomb. This is also what the Yamaha factory gncc guys are running. Also, strait from them, take off one of the engine braces. It will let the frame flex. Also, from them, set your forks in the triple clamps at 263mm from the center of the axle to the bottom of the triple clamps. About 100mm of sag in the rear. Your jetting is probably very close. I would not mess with a jd kit.

As for suspension, the forks have 47kg springs stock. I happened to have some 44kg and put them in one day cause I had nothing better to do. I gotta tell you in the woods it is magic! You would think that is would blow into the stiff part of the compresion but maybe it is the speed sensitive valving or whatever but it really works great. I run my clickers pretty much stock. 13/50 gearing, higher handlebars, gripper seat with a bump, steering damper and some cool stickers and you are set for the woods. One other thing, a little flywheel weight and a rekluse is nice too.

thanx alot guys , suspension will probably be the first thing i adjust , then throw on the fmf q4.1. Does anybody know do those spark arrestors cut back any power or performance?. Its law to have one in to ride in the bush in B.C canada.

Does anybody know do those spark arrestors cut back any power or performance?.
The ones in my DRD pipes are unnoticeable. The only problem you might ever have is if the muffler starts blowing shredded packing up against the screen.

I have an 08 450 and i put a megabomb and factory 4.1 on it and it feels like a whole different bike. It pulls everywhere. I can jump just about anything in second. I didnt need it but its def worth the money.

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