New Bike Questions

Hey All. I am the new owner of a 03 wr450f and I took it for its first ride this weekend. I was running in the 5000-6000 altitute. I have the endcap removed and the snorkle out. I noticed a lot of popping after releasing the throttle and there was a big bog off idle when I went to pop the front wheel over an obsticle. Is this a sign of being way too rich. The dealer "said" he performed the service bulletin, but failed to punch the vin. So I'm guessing that he opened the air screw a couple of turns. Would this have made my bike to rich? I'm not quite ready to get into the rejet stuff, I just want to go out and ride. How can I get this to run normal at that altitute and at sea level? Can I just close the screw a turn or two?

An advice for a newbie would be greatly appreciated.

Spend the 65$ on the James Dean kit Jet kit and all your problems well be solved. It is real easy to install. My bike ran like crap untill I installed my JD kit. Know I can't keep the front wheel on the groud :)

Is there any other suggestions besides rejetting?

Since your removed the intake/exhaust restrictions, the bike is running lean. Turning the fuel screw out (counterclockwise) will richen the idle mixture. This could help with the popping on decel, but, it may not be enough without rejetting. The bog off idle is usually a "too rich" condition with the needle, but, that seems weird since you uncorked the bike and have the stock jetting. Try moving the needle down (move the clip up) one slot, this makes it leaner on the transition. If it bogs worse, move the needle up one slot from original (move clip down). This makes it richer on the transition.

wrkaholic is right on! You have no choice but to rejet. If you can't do it have your dealer do it. It must be done so you don't burn up a piston running to lean. :)

This is a update on the jetting:

Per everyones advice I took the bike to the dealer to see if he would rejet. He did. What he did was go from a 150 to 155 m.j. and turn the fuel screw out three turns. Its still seems to pop a little bit, but that was a back of the truck check, I'll know more after I ride it. The bike will die if you go from idle to a bunch of throttle as well. Ca someone explain what the dealer did? Did he richen the bike of lean it out. Is this enough jetting? I see everyones sigs. that have long list of jetting setups and I have no idea what they all mean or how to figure out if they are right for me. Is there anything else I should do if it continues popping. I ride at all elevtions from sealevel to 6000+ so I looking for an all around setup. The bike has plenty of power stock, so I'm not looking for major power gains. I just want to ride the bike and not worry about putting a hole in the piston.

Thanks for all the help

You are good with the 155 main but the stock needle is designed for a corked up bike. get the JD kit and put the red needle in position #4. As for the bog down below you may have to turn your accelerator pump screw in a 1/4 turn to prevent a too rich squirt upon opening the throttle from a closed position. :)

I ran the bike at 6000 feet elevation and tested the setup. It popped a whole lot less but it still boged real bad. I moved the clip down one and seemed to help higher in the RPM's but not the bog. How do I adjust the accelerator pump screw? Is it something that can be done without pulling the carb?


Yes it is behind the right side carb cover. Take the 2 bolts off and you can ride around on the street or parking lot with the cover off. The black cam with the gold screw is what needs to be adjusted. Instructions are found in the factory manual supplied with the bike. I would start with a 1/4 turn inwards (clockwise) Keep track of where your adjustments are so you can get it back to the original position. I bet you are getting to much duration on your squirt which gives you a too rich bog. :)

Well I've tried a couple of different setups and the bog is still there. right now I'm at 155 main, 48 pilot and I moved the clip down one. The bike rips, but still has the bog. I messed around with the accel. screw and it didnt have any effect on the bog. My fuel screw is about 1.5 and the bog is at elevs. of 500 and 5000. Am I moving in the right direction? I was tempted to go with the JD kit, but as I uderstand, all that you change is the main and the needle which wouldnt help with the off idle bog right?

Any other suggestions?



Save yourself the trouble and just order the JD kit. Go read my post thats entitled You Da' Man JD. This kit is the bomb!! You will notice a huge difference!! Chuck

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