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About RockIslandRider

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    TT Newbie

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  1. RockIslandRider

    2008 Yamaha WR450F Mods

    Looks like you are on your way. I assume by now you've done the AIS removal kit, and ALL of the "free mods" posted on TT. These are all excellent and necessary mods to "uncork" the stock bike. I have an '08 WR 450, and almost have the machine dialed in. The following worked for me - can't say it will work for you - but my bike pulls like a tractor... and flat out halls butt when i'm not in the forest. NOTE: the heavy fly wheel tames down the "yank" that a YZ produces... and helps maintain momentum in the technical stuff. Depending on your riding style and where/what you ride, you might want to consider some of the following: yz 450 exhaust cam - somewhat expensive, but great improvement in performance. Definately worth the bucks. The '07 and '08 cams have sligthly less overlap than earlier models. I used an '07 YZ exhaust cam. You will need to re-jet the carb. You are at 7,000 ft., so I don't know how to advise you on jetting, except you want to mirror the jetting for a YZ 450. You will need to by-pass the Air Cut Valve. Look for the Air Cut Valve post on the TT site. Use a #100 pilot air jet - #70 is stock for the WR. Buy a stock YZ needle (NFLR) unless you want to spend the $ for the JD kit. Buy the JD kit for the YZ, not the WR. At 7,000 ft. you might need a leaner needle. On second thought... but the JD kit. YZ exhaust header. Much larger diameter, more free flowing. The '07 YZ 450F Exhaust header will bolt right on. Don't try to order an OEM graphite gasket, because they don't make one for this mod. Go to NAPA, and but a sheet of Fel-Pro 2499 Pro-Ramic high temp gasket material. It comes in a 12" x 28-1/2" by 1/16" thick sheet. Motor heads use this for home made exh. gaskets. You may have to special order. Cut a piece about 1-1/2" wide and wrap it around the YZ header. Make sure the ends butt up perfectly. Slide the stock exhaust pipe over and clamp it down. It fills the gap perfectly. This will help mid to top end. I didn't notice much loss on the bottom, but i did this mod at the same time i dropped in the yz exh cam. I don't have a big budget, but you can use the same principle with an '07 YZ mega bomb or power bomb header. Buy a couple of new rear tires. You'll need them. Power Now is a great mod if you do allot of tight technical stuff... and have an extra 100 bucks. I hope you have your MSO. If you do, make your bike street legal w/ a Baja kit. Spend the money for a Trail Tech Vapor. If for any other reason, it has a coolant temp sensor and a tach. Aloha and Good Luck