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YZ Pipe Jetting for WR

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Hello ... i just recently bought a YZ250F exhaust pipe (2004) for my 06

WR250F and i need to rejet the bike. I am a newbie with jetting. I have done the throttle stop, grey wire, and airbox mods and i will be installing the new pipe this week. I currently have stock jetting and i would like to know what i would need to change the jetting to for the bike to run nicely... i live in CA... in the winter is gets to the 50s and summer 100's where i ride, and the altitude is 1000 to 3000 feet. Any jetting info would be great, thank you

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Man you did exactly what i did to my bike even the same pipe year and i live in the same altitude as you. But back to your question it made mine run lean an 06 by the way. on the main jet i had to go from a 165 to a 178 now that should set you up right but one of the ways to check to see if your runnigng right is to check your spark plug if its cinnamon color your perfect but white is lean so just play with it

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haha yeah i needed a new pipe so decided with the YZ pipe... hows that pipe for you? so basically the only thing i need to change is the main jet not the leak jet or anything else correct? thanks alot for the help man cause i had no clue what i was doin haha

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You might need to richen it up a little, see how it runs first.. I mean find a long flat straight away and play with it at different throttle positions. Get into like third gear and at mid throttle, then open it up .... is it responsive? does it pull from there to wide open throttle? or is it flat like it has a rev limiter? this will give you mid range info, like the needle itself or the clip position.

After doing the mods to my bike I had it on a familiar fire road and opened it up in fith, the bike was flat, like I was looking for another gear, I went up on the main jet and it made a world of difference.

When the bike is warmed up does it start easily or does the motor turn over 4 - 7 times before it fires?

I dont know what the guys are doing with the newer WR's but with my bike (01') I had to richen everything up.

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