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Dan250

Pilot size dilemma 45 or 48

3 posts in this topic

With the 45 pilot the best idle was 3+ turns out. Changed to a 48 now seams to idle best 1 turn out or less and won't kill the engine if turned all the way in. Just put it to 1/2 turn out. This was adjusted a low elevation but ride up to about 4000 or so. Any suggestions.

The 07 wr450 is mostly stock accept for, cut throttle stop, 48 pilot, 165 main, AP O-ring, GYTR exh tip and GYTR air filter with snorkel removed.

Going to change to a FMF Q4 soon if that will make a difference. Thanks

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Sometimes, the pilot jet size you really need is half way between the two, like a 46.5, which does not exist.

I assume you have an extended fuel screw. I would prefer the smaller pilot opened a lot Vs. the larger pilot and the screw nearly closed. On most of the extended fuel screws, there are grooves. First, I remove the float bowl, I use a 1/4" drill (nice and sharp) and bore out the bowl slightly. Do it carefully and make the drilled hole finish as nice as you can. I put the bowl back on the carb and put a second oring in one of these grooves. This will enable you to safely have the fuel screw at 3 turns as the second oring on the screw shaft provides additional friction to hold the screw from vibrating out of position or worse, falling put all together.

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The 07 wr450 is mostly stock accept for, cut throttle stop, 48 pilot, 165 main, AP O-ring, GYTR exh tip and GYTR air filter with snorkel removed.

Substitue a twin air filter for your GYTR and a PMB exhaust tip for your GYTR and thats pretty much my set up I'm running.

With the MSR fuel screw, mine runs good anywhere from 1.25 turns out for hotter weather all the way to 1.75 turns for colder weather. It just takes a little time to dial it in. The bike didn't exactly run perfect when I first put the 48 pj...but now it runs great.

With the Q4, I'd think about puttin a 168 main in there especially if your running the stock needle.

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