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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.

Cheers.

Edit...

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.

(3rd-5th)

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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