05 CRF 450 Jetting problems with JD Kit

Took out my new bike today for the first time. It was a bear to start and once started it poped and backfired like crazy. It was also cutting out a bike out with a quick chop of the throttle and basically ran really lean. It came stock with a 168mj.

Before I ever even started the bike I put the JD Kit in. I also put in the zip ty screw and the Twin Air screenless filter kit. THe JD Kit calls for the Red needle in the 5th position from top. It also called for a 178mj at my elevation 0-3000 ft. Temp today was around 70-80. I put in a 180mj when I got home and it helped some with the backfiring. I also tightened my Zip Ty Screw to try and help the cut out when I chop the throttle. There were too other guys at the track with stock jetting who had no complaints on their new 05. Anyone have any ideas what I should try? Would lowering the clip on the needle richen it more than a bigger mj? Its kind of like I am rich in the pilot and lean in the main??? Not sure where I am at with the needle. Thanks guys!

You'll have better luck on the jetting forum. JD answers questions personally.

I have the same set up. Use the 175 main (JD's suggestion for 2005s). Red needle in the FIFTH position (from top). I have a Zip Ty as well. When I went to the track earlier today, I had the same pop when decelerating. I adjusted the fuel screw to 2 1/4 turns out and the bike ran really good.

Put back in the stock needle and a 170mj to compensate for the screenless filter (168 is stock) and the thing runs like a champ. No popping or backfiring whatsoever. I also got rid of the downlow bog with the zip ty screw. Wonder if the JD Kit for the 05 still needs some fine tuning? Dovi, If I put the clip 4 down from the top and use a 175mj I am worried that it will act even worse than it did with in the 5th from the top and a 178. The kit I got from JD said to use the red in the 5th and a 178.

Put back in the stock needle and a 170mj to compensate for the screenless filter (168 is stock) and the thing runs like a champ. No popping or backfiring whatsoever. I also got rid of the downlow bog with the zip ty screw. Wonder if the JD Kit for the 05 still needs some fine tuning? Dovi, If I put the clip 4 down from the top and use a 175mj I am worried that it will act even worse than it did with in the 5th from the top and a 178. The kit I got from JD said to use the red in the 5th and a 178.

I had the same questions you did and did some research in the jetting forum. According to James Dean, the instructions for 2005 are the same as the rest of the years except to run a 175 main instead of 178.

You are right about 5th position from top with the red needle. Sorry - I was going off of memory. :cry:

The popping on deceleration can be cured by mearly backing out the fuel screw a little (richer). According to James Dean, however, there is no need to go to a richer slow jet.

Have no fear about the JD kit - it is as impressive as ever. The bike ran ridiculously fast with the screen removed and the JD jet kit installed. The throttle response was crisp too. :cry:

I only have 3 hrs on my new bike,,and there's no hitch in the giddyup with stock settings so far

I just put in my JD jet kit in my 05,the 175 main,red needle in clip 5 and 2 turns out on my storm screw.ran great no popping on acceleration or deceleration.pick up was better off the bottom as well.

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