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DRZ400S Jetting question...

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Hi all...I have searched, and gots lots of different ideas, but i have some questions specific to my bike...Please let me know if you know of a similar setup, or believe you know the answer.

I just bought a 2006 DRZs with:

FMF Exhaust

FMF Header

K&N Filter

I am planning on doing the 3x3 mod and re-jet...

I do not believe the bike has ever been re-jetted, and does not run as well as I think it should...especially at 0 to 1/4 throttle. I have minor experience with some jetting issues on streetbikes, so i know my way around a carb. Now, i just got the FMF Powerup kit (stage 1 Dynojet) and do not think with the 3x3 mod from my own experience and what I have read on here that all the Jets in the kit will be the appropriate sizes.

I know that each bike is different, and no-one can tell me the exact sizes, but i have seen suggestions on others bike to use a 155 -140, all with the 25 pilot.

Some say use the stock (142.5 Mikuni = 152 Dyno)...

So, while I am not particularly unhappy with the main as is, I need the low end to run better, so I figure if there is a better solution, i might as well try it while i am in there. Minor backfiring on deceleration, terrible transition @ 1/4 throttle in all gears (very jerky power surges), and I think it feels a little flat on the main.

Before I take everything all apart, I am looking for some suggested setups, and potential online retailers who have what I need cheap.

Please let me know if you have a strong feeling (and experience) to guide me, not really interested in my buddies buddy runs a blah blah blah...i can find all that through Search.



90% riding is at or near sea level in hot dry conditions...

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Could you post the 25 pilot jet link for ease of finding.

I have 2009 drz400sm with: Yoshi rs2 full exhaust, 3x3, and DJ kit but it didn't come with the pilot jet or the extended fuel mixture screw. So I would like to order it from you guys.

Question: I have all of the parts installed and currently having issues with mid range acceleration and cruising speeds but only at the higher gears.


Would not changing the pilot screw affect it?

I went by the directions: 155 main,and the needle on the second notch down from the top. Any advice.

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I dont know what the deal is. I have been tinkering with the carb and not sure what is wrong. I have went over my work time and time again.

I had : 155 mj

25 pj

DJ needle on the second notch down from the top

3-3.5 turns out

Currently : 150 mj

25 pj

DJ needle on 2.5 notches down from the top.

and have been playing with the mixture screw with no luck

No matter what I do I still have the stumble on accel and when 1/4 to 3/4 throttle just cruising. Am I getting to much fuel or not enough?

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Well the package say's DJ 3110.001 US model only 2005-2009 DRZ400sm.

So I have been going over all of the instructions from the DJ kit and the exhaust. The DJ kit instructions say to install MJ 155, E-clip in the #2 groove down from the top and mixture screw 3.5 turns out.

The exhaust instructions say install a MJ 145, PJ 25 and install the supplied shim on the stock needle. So Im not sure what to go by.

I have been reading just about all of the threads on here, and what I am thinking is I should just be moving the needle down a groove.

So here is what I am going to go try right now.

Main jet 155

Pilot jet 25

Needle #3 groove down from top

What do you think?

Its stock carb.

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So here is the setup....

MJ 155

PJ 25

DJ needle 3rd groove down from top

Mixture screw 2.5 turns out

With that said... I took it out for a test ride and it was diffenently better.

Though it still has a slight stumble 1/2 to 3/4 throttle when cruising but way better then it was. So for now I will leave it so I can ride.

So if I get the bike to the dyno would they be able to see where the bike it lagging?

Question: How do I tell if the bike is running lean/rich other then backfiring?

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Well to be exact 3x3.5

Yosh RS-2 full exhaust

I was wondering if removing the spark arrestor was bad for the engine in the long run?

Thanks very much for your reply. I was reading about you in the faq section and you seem like a very busy man.

So I realy appreciate the help.

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its the 3x3 mod,not the 3x3.5 mod.

removing the spark arrestor has no effect on the motor.

the jetting needs to be

160 main jet

clip 2

25 pilot jet if you are using the stock fuel screw

2.75 turns.

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See I wasn't sure if it was suppose to be exactly 3x3. Looking a pics on TT they diffenetly are not exact. I guess I am glad I didn't go with the timplet the yosh instructions came with because it was like 3 1/4 by 4 1/2.

Well I am going to fix the mistakes I have made. Thanks again for the help.

I am using the extended fuel screw from TT.

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Main jet 160

Pilot jet 25

2.75 turns out

2nd postion on needle

Wow the bike is running great. So I am curious what the difference would be after putting the 22.5 back in?

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