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warden415

Pilot screw and bog issues? 2003 wr450

9 posts in this topic

I just installed an aftermarket pilot screw. I set it at reccomended adjustment. The bike hasnt run in a month and a half due to being torn down and parts at the powder coater. When I tried to start it, the battery was dead but it did start second kick. There is a serious bog coming off throttle now and a pretty good flame shooting out the exhaust. Never had the bog before. I assume the pilot screw is off and it needs leaned out??? Any suggestions? Also could the battery being dead have anything to do with this? thanks Steve

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Clean the pilot jet.The recommended adjustment is only a starting point. You will probably need to fine tune it.

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What is the current state of tune of the bike?

Stock pipe?

Stock airbox?

Stock jetting?

More advice is forthcoming with this info.

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The bike has a stock head pipe, FMF Q slip on , stock jetting, uncorked and all free mods done. Engine stock except for it has a YZ cam. It was in it when I bought it, thinking of going back to the original cam

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The bike has a stock head pipe, FMF Q slip on , stock jetting, uncorked and all free mods done. Engine stock except for it has a YZ cam. It was in it when I bought it, thinking of going back to the original cam

I think Maxtherat is right; you're pilot circuit is clogged. I am new to WR's , but I think a JD jet kit, and an adjustment/instpection of your APump circuit is in order too.

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Here is one more point. When i took the original pilot screw out the carb was still on the bike, I didn't see the o-ring come out???? I got a small piece of wire and fished around to see if I could find it? I never did, now it may have fallen out when the screw came out but I never saw it. The new pilot screw went right in no problem. My fear was I now had 2 o-rings in there? Now I wonder if that is the case and whats causing my problems?

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If you don't have the o-ring and washer in there to make a seal then it can certainly be extra lean. At this point it is probably best to remove the bowl and inspect. Check your PJ while you are there. You probably need to rejet as well depending on your altitude.

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Your pilot jet could be clogged, but it could also be that you need to richen the jetting for the cold weather. I doubt there are 2 o-rings on the pilot screw because that would make the pilot too rich; your problem sounds lean. Either way, you should pull the carb to check it out, clean, adjust.

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Well I messed with the pilot screw a little tonight. I took it from 1 3/4 out and started adjusting, What I have now is about 1 1/4 out. Seems to have helped a good bit. It may not be spot on right now but it appears much better. We are covered up in a ice storm so I cant get out and ride. I am just running it and making adjustments in the basement with the exhaust pipe sticking out the door. Thanks Steve

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