jetting

My elevation is 2500 ft. and temps are around 80-100 degrees. should i still up the pilot jet to a 45 or stick with the stock 42. i have a 2006 YZ450F.

I run a 48 in my Yz400. Stops the decel popping, and easier to start. One of the best mods I ever did was to get the JD Jetting kit. I read all the kudos from others, but could not see spending $50 for 2 needles and a few jets. Finally did it. I tell you, the needle for sea level to 5000 ft is worth every penny. I cannot believe how much smoother it accelerates through the entire range.

My first question in a jetting thread is always "How does it run?"

There is no fix-all recommendation for jetting. Every bike is a little different and the conditions, climate, and elevation that you ride in all factor into the jetting.

Does it hesitate, pop, backfire, or bog?

80-100 degrees at sea level:

45 Pilot

165 Main

Runs like an absolute bear....I do agree with ovrrdrive though you have to go by how it runs and start from there. You may be able to just adjust the fuel screw to start with.

My elevation is 2500 ft. and temps are around 80-100 degrees. should i still up the pilot jet to a 45 or stick with the stock 42. i have a 2006 YZ450F.

I would. We've run ours with a 45 at altitudes ranging from 2000-3500 feet so far, and it works fine

45 Pilot, 165 main, needle on the 4th spot.

45 Pilot, 165 main, needle on the 4th spot.

Still.....have you figured out how to stop making popcorn on decel?!?

I have that other needle on order....(the Dubach recommendation from the other thread)

Still.....have you figured out how to stop making popcorn on decel?!?

I have that other needle on order....(the Dubach recommendation from the other thread)

Mine doesn't pop but I'm running a 48 pilot, 168 main and stock needle on the 4th clip. I tried my Honda needle and it was no good, far too rich.

Mine doesn't pop but I'm running a 48 pilot, 168 main and stock needle on the 4th clip. I tried my Honda needle and it was no good, far too rich.

I am little confused on the low end/idle. I am running a 45 pilot and sometimes my idle hangs up and pops like mad on decel (lean). When I was running a 48 I was getting little black puff everynow and then but no poppiing on decel(rich). My choke doesn't seem to do much to my idle speed. 4th clip, 2 turns out, 165 main.

I am little confused on the low end/idle. I am running a 45 pilot and sometimes my idle hangs up and pops like mad on decel (lean). When I was running a 48 I was getting little black puff everynow and then but no poppiing on decel(rich). My choke doesn't seem to do much to my idle speed. 4th clip, 2 turns out, 165 main.

Go with the 48 and adjust the fuel screw in until you aren't puffing any more. :thumbsup:

I have a 45 pilot and 168 main, Tusk fuel screw out 1-3/4 turns. Check that the idle screw is not out to far, when I was setting up my jetting the idle screw was out to far and it caused the idle to hang occasionally. I would also check to see if the fuel screw is still there when it falls out you're bike will decel pop like crazy.

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