Requesting YZ Jetting Recommendation

[mhays01]

I’m getting ready to go to YZ timing. I’ve tried to read every post concerning this topic and would like some final options and tips on jetting.

Current setup is a 99WR, FMF PC IV2SA, PowerBomb, TwinAir, Air Box top removed, Altitude 0-1000FT , 50% MX-50% Trails.

It seems like a popular configuration would be DVP#4, PJ 48, MJ 172, Fuel Screw 1.5. But, based on the post the E** series needles might be interesting.

I’m also planning de-octopussing with the PAJ #100 and YZ Start jet #65.

I’ve ordered the following parts.

5BE-14916-DP-00 NEEDLE (#DVP)

5JG-14916-EN-00 NEEDLE (#EKN)

5JG-14916-EP-00 NEEDLE (#EKP)

3TJ-14948-06-00 JET (#48)

7A9-14943-27-00 JET (#100)

3TJ-1494F-13-00 JET (#65) (YZ STD) (Start Jet)

4MX-14943-40-00 MAIN (#165)

4MX-14943-41-00 MAIN (#170)

4MX-14943-42-00 MAIN (#175)

4MX-14943-93-00 MAIN (#178)

Any advise or opinions would be appreciated.

Mike

[James_Dean]

Mike,

Here are 2 options to pick from:

1)Needle DVP - More responsive than stock, clean running, controlled revving, lean in mid-range relative to "standard" Keihin needle.

#48 pilot jet (**)

#100 pilot air jet

3/4-1.5 turns out

DVP needle clip #4 or #5

#172-#180 main jet

other jets stock

2)Needle EKP or EKN - More mid-range power, wheelies quicker, "The engine and the power that it produces now feel more wired to my brain"(John in L.B.- see "EKN needle results"), not always as tractable, '01 YZ426/250 use this, "standard" Keihin needle taper.

#48 pilot jet (**)

3/4-1 1/4 turns out

#100 pilot air jet

EKP#3 or #4 clip (or EKN#3 or #4)

#165-#172 main jet

main air jet #200 (or removed with #172 main)

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(**)A #45 pilot jet may be preferred at higher altitudes and warmer temps, expect 1 1/2 - 2 1/4 turns out on pilot screw.

An adjustable pilot air screw is a good addition also.

Good Luck! ?

James

[Tree_Crippler]

Great answer James! I just printed it out so I can just give my friends a copy. Thanks.

[mhays01]

James,

Thanks for the excellent reply.

It's exactly what I was looking for. It was a great answer that consolidates a lot of testing and experimentation into information that usable by everyone (e.g. novices like me). I think that the usability is proven by Tree Crippler’s intentions to give copies to his friends.

Many Thanks,

Mike

[James_Dean]

Mike,

Your willingness to purchase all the jets and needles was worth giving a more complete response. You're welcome. Feel free to post questions if you have any difficulties getting it adjusted.

James