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Discussion Starter #1
:?: I have the Yoshi Pro Titanium Slip-on and the Noss Machining No-cut Billet Flange with K&N Filter on the way. I understand that you want to create a lean condition, by as much as two jet sizes under stock and four under modified, for the Dial-a-jet to work properly. I also understand that the factory presets the Z400 to run on the borderline of being lean. Question: Will the Air and Exhaust mods I have, keeping the factory jetting, be a lean enough condition that I shouldn't have to change the stock jetting when I install the Dial-a-jet? Thanks in advance to anyone who can help...
 

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Are you going to be modifying the airbox or snorkle (I.E. removing or drilling holes in either of them)? If you do that, you will definitely have to rejet.
 

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Discussion Starter #3
I could run without the airbox cover I suppose. I had also looked into those TPI inlets from Thunder Products...nah...probably just run without the cover...with the outer-wear for the filter, it should be okay. The thing is I want to create that lean condition for the Dial-a-jet to function properly....I am just not sure if it will be lean enough.
 

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If you are running with no cover and a K&N, you will be way too lean for the Dial-a-Jet. If I am not mistaken, they will go like 4-5 jet settings by increments of 2.5 (130, 132.5, 135....etc). Stock Jets are at 130 (I believe) and you would need to be jetted somewhere around 150-155 range and then use the Dial-A-Jet to be effective. Someone with a Yoshi setup would be able to help you more on what they are set at. Check with "biohazzard 1.2" because I think he is running the titanium full exhaust. There are others here as well. I hope this helped, it is just from my understanding of the Dial-A-Jet. There are some here with the dial-a-jet setup also so they would be able to help.
 

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Discussion Starter #5
Thanks mre2u84. I will see if I can get a message to "biohazzard 1.2" to ask. When I asked Thunder products about it, they said that is I was leaving the air and exhaust alone, then I would definetly need to go to smaller jets to lean it out a bunch.

If I understand you correctly, you're saying that with the exhaust and K&N mods, it will be way to lean, so much so that even the Dial-a-jet won't be able to compensate...is that correct?
 

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Yeah, like I said, I think that the stock is 130 and you will need to be in the 155 range (about 10 jet sizes away) meaning you will need to rejet anyway. From memory, I think that they (Thunder Products) said to jet 2 sizes too small and then install their product and adjust from there. That should give you the lean settings that Dial-A-Jet can adjust to compensate.
 

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MRE2u84 is right!

I started at 150 (main) and ended up with a 160, needle in stock position and 2.75 turns out (this is the main dial in...as the air screw is the least "engineered" aspect of tuning!

Have fun and keep playing with the tuning....mine was really good right from the start (had the shop tune it...manager used to race DRZs and cross country on hopped up wolverines)

We got some really good gains from pulling the snorkel off and experimenting with dif filters...the stock is most constrictive, I had bad luck once with K&N (not tried this time), unifilter...very good, the Best one for my set up was the Twin air set up on an adaptor plate...I used NOSS manufacturing's version. I also use either split fire or Bosch Titanium plugs in a "hot" version. I think the splits give you more low-mid...the titanium plugs seem to HIT at the TOP end....something about the temp and volt of the spark...vs amps....

I think NOSS is a member on here.

Take care!
 

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Discussion Starter #8
Man this site is great! Lots of great info. Thanks for all your input guys. Took everything off last night...tinkering....getting ready for the parts. :D Exciting! Wish me luck and I will try to get back on here when its running again to let you know how it all turned out. Thanks again mre2u84 and Biohazard1.2... 8)
 

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Where are you looking to buy that dial-a-jet. That would be nice for me cause where i live were 6000 feet but when we camp we will ride all the way to 13,000 feet peeks an hour away in CO. tyfneinfo


I'm a pc person, i build em for years now so excuse any dumb questions i may spurt out. lol When at high alt like 10K+ does it run lean'er or rich'er. :?
 

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Discussion Starter #10
Less air density=Richer, more air density=leaner...so higher altitude=less air density and sea-level=higher air density....mines on order from Thunder Products at www.thunderproducts.com but their page has been down for a couple of days...
 

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Thats what i thought but i wasent sure. Interesting, maybe thats why ours aint being sold jetted but there piped with headers. *Shrugs* I want to put my K&N on but i'm afraid it wont run, lol. I know if i take my lid off it dont run worth a crap. Plus pulling that box aint looking too fun either. :D O-well i need to change to my K&n by 2 hours guess i better hop to it.. DOH!!
 

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yes

works GREAT!

look at my signature to see what I am running.
 

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Discussion Starter #13
So craZy400....mre2u84 said stock main is 130 and you went to 145 with air/exhaust mods and your dial-a-jet w/snorkle is working great. Sounds great.

Just to be sure on this...the jet sizes are reversed right? 130 is smaller than 145, but allows more fuel because it takes up less space in the fuel flow passage. Therefore, when we use bigger jets, we are not referring to the actuall size, which is smaller, but rather the amount of fuel allowed to pass which is bigger....correct?
 

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The bigger the number the more fuel added.

Here is the deal with the DAJ (Dial A Jet).

It will cover 4 to 5 jet sizes from what I have seen so far. Since our carb MJ sizes jump in increments of 2.5 (130-132.5-135-137.5....and so on) you need to be jetted within 4 to 5 sizes of CORRECT jetting.

I should be running a 152.5 with my mods so I jetted a 145 and then adjusted the DAJ up 3 hole sizes to be at the 152.5.

You can lean out the DAJ but REMEMBER you are always adding fuel so you never want to put the CORRECT jetting in because you are adding fuel and it will be too rich.

Does this make sense?
 

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Discussion Starter #15
That does make sense, but from what I was able to gather, the DAJ does nothing unless the lean condition is created.

The sonic signature created in the intake manifold is what aggitates the DAJ causing the fuel/air emulsification to occur. The accoustics that the DAJ operates from only occur when a lean condition exists. So if you are perfectly jetted and have a DAJ installed, it would never add fuel because the condition to trigger it wouldn't exist.

That's why I was inquiring about leaning. I wanted to create the condition where at my altitude in Ohio, I am running maybe 2 sizes two lean. That way, when I add the DAJ, that lean condition exist and I can start at maybe a setting of 3. That would give me 2 up and 2 down so that I could explore surrounding states, trails, elevations, and weather changes.

So I have the stock jets that I understood to be borderline lean given the stock airbox, filter, exhaust. Suzuki already has a titanium header on it stock. I added the Yoshi slip-on and will be going with the K&N filter, probably with no snorkle, or maybe even no air box lid, since I don't like the mud after my first time of having to clean it off...LOL.

Now if it truely is bordenline lean...and I made those mods....it should be lean enough that I will not have to rejet to lean it out anymore. So I am hoping to be able to install the Dial-a-jet and given the lean condition that now exist because of those mods....I am hoping to be good to go. That's my understanding from speaking with the people at Thunder Products and various articles from the research I have been doing. Does all that crap I just wrote sound right? :?
 

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for the most part.

i find it hard to believe that it comes from the factory on the lean side. i would think they would richen it up to prevent lean-burn-down waranties.

i would bump the jet up a few sizes. remember they only increase by 2.5.

rejetting is SOOOOOOO easy. you don't even need to take the carb out to do it.

the SUPPOSIDLY hard carb bowls screws aren't hard to get out if you have a long #2 phillips.

good luck
let me know how it goes
 

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Discussion Starter #17
I really don't know if they come rich or lean, but only 3 or 4 sources out of about 15 is saying it comes rich or slightly on the rich side.

Guess the best thing would be to do the testing myself. Mark it off and do some new plug Roll-ons/offs at full, 3/4, 1/2, 1/4, and idle. See where I stand on each, rejet accordingly and do it again until I establish a nice lean burn at each phase. After that, install the DAJ and run through the whole test again. Sound good?

I wasn't even considering where you guys are located either. craZy400, you could be living on K2, PrEtEnDeR in Hawaii, Biohazard1.2 around the corner from me, and mre2u84 in Iraq(if you are then get on your Z and head for Kawait quickly...
: ).

Hey, serious thanks for all the input guys...it at least spurred my brain into more research, and it was fun to :wink: Take care everybody and I will try to get a message to each of you with my findings.
 

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Discussion Starter #18
Okay everyone, I started testing this is where I am so far. Also, pulled the plug to take a gander at it before beginning...looked kinda rich...kind of a black, soot...not oily, except for the plug electrode itself which was looking the way I want the rest of the plug to look.

Configuration:
stock 130 main jet, installed the Dial-a-jet in my airbox to carb booty, and set it to three, installed the Low-boy TPI valve on Airbox lid and opened it.

Result:
Running lean and lacking power.

Configuration change:
Closed the TPI Low-boy vlave

Result:
Still running lean but very, very noticable difference

Configuration change:
Turned the Dail-a-jet down to second position(1 click richer)

Result:
Noticable power gain

Configuration change:
Installed 140 main jet, opened TPI Low-Boy valve, Set Dail-a-jet to position 5(full lean) (NOTE: mainly in preperation for installing the K&N filter)

Result:
Ran beautifully and pulled hard, hard, hard. Loved popping around the trails in second gear and then cracking on the throttle, instantanious response and it took some getting use to.

Initial Conclusions:
Great to be able to Dail-a-jet. They weren't kidding about the throttle response either. I would be idling around almost stalling it in second...crack the throttle and that thing would come up as if it were on a bench. The low-boy valve also is a great investment. For each of the five Dial-a-jet settings, you can now fine tune them.

Will try to get back when I get finished dialing it in. But probably won't have time to 8)
 
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