03 450 Jetting help

I have and 03 450 that I bought new. Ive never modded it much until recently when I got back into dirt riding. It has the airbox snorkel removed and holes drilled, a white brothers air filter and e series exhaust with all the discs in, and gray wire cut. Currently it has a 152 main, 48 pilot, 65 starter, 70 paj, 70 leak, and was 3.5 turns on the pilot screw. I have never felt any off idle stumble but just constant throttle stumble. When riding at constant throttle, 1/4 throttle, it stumbles but if I pull the choke it runs better, even when warmed up.

What sea level are you at? Seems like your needle could stand to be raised or just go to a larger Main jet might be best. I am running a 170 Main in my 04, needle in stock position.

What position is your needle in?

I am at about 600' above sea level. My needle is in the 6th out of 7th position.

I am at about 600' above sea level. My needle is in the 6th out of 7th position.

From the top? If so, you for sure have too small a Main Jet. Avg. position of the Needle is in the middle, give or take a notch either way. Stock Main I think is 165 and yours is set up for a high altitude. I am around 500-600 Ft above as you are.

I would at least go back to a stock Main and maybe more, I went from 165 to a 170, and move your needle clip 3 notches down from the top. This should fix you up.

From the top? If so, you for sure have too small a Main Jet. Avg. position of the Needle is in the middle, give or take a notch either way. Stock Main I think is 165 and yours is set up for a high altitude. I am around 500-600 Ft above as you are.

I would at least go back to a stock Main and maybe more, I went from 165 to a 170, and move your needle clip 3 notches down from the top. This should fix you up.

Ditto, I'd try a 168 - 170 main, clip #3, and fuel screw 1.25 - 1.5 turns out as a starter point.

The clip is in the 6th from top now. would the 3rd from top be richer or leaner? I put a 168 main in, 48 pilot, 40 leak, and 100 pilot air jet. I also got an adjustable air screw. The air screw, leak, and paj are on order and due in on thursday

3rd from top would be leaner, but everything interacts together.

Check this out:

http://www.thumperfaq.com/jetting.htm

Your the original owner, and your positive it is the stock needle....right?

I can't imagine why a dealer would jet a bike like that...but...well...you know how some dealers are... :/

Look for "color" on the top of the needle...red, or blue....like this....

http://www.pbase.com/jdjetting1/image/38163739

just to see if it may be a JD needle somehow.....

I didn't need to mess with this, what is the stock pilot air jet size? i plugged my leak jet, #35 still did not work well for me.

I am the original owner so it is the original needle.

Try this:

165-168 main; 152 is really lean.

3rd clip needle; 6th clip may have been to compensate for the very lean main.

45 pilot, 2 turns; I only find the need for a 48 when it gets cold (< 50).

40 leak.

No real need to mess with the starter or pilot air.

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