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sirhk

SoCal Jetting Favor

60 posts in this topic

I would like to jet my bike and learn about all the qwirks that come along with the Carb. I'm very mechanically inclined and wouldn't think twice about rebuilding the motor myself but when it comes to the carb I'm scared to touch it. Would anyone be willing to do a hands on tutorial of jetting this and showing me what changes do what? I'd be willing to meet you at a local track, riding spot, or the desert to do this. Give me a list of parts to buy and bring, jets, needles, etc... I hear about all these wonderful things but don't want to pull it apart only to never have it run right again.

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Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

[This message has been edited by sirhk (edited October 08, 2001).]

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I'll help you out Khris.

If I remember correctly, you experience a slight popping under deceleration, right? This should be easy enough to fix.

The problem is we have to know what your jetting is now before we can get new jets. Any chance you could dig into it to see what size jets you currently have?

I would recommend going to a larger pilot jet for starters, then experimenting with the main jet and needle clip settings. I'm dying to ride again! Even if we spend most of the day wrenching, getting out of the office and into the desert will do me good. This coming weekend does not look good for me. Let me see what I can do…

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Sounds good to me Ron!!! Yeah, this weekend I shouldn't go to the desert for money reasons. My Explorer is in the shop right now getting regeared (finally I'll have some power and my tranny won't be roasting, hopefully!!). They are having to replace a axle and some bearings that were shot and it's going to cost me about $1500 so I'm going to be kinda tight on cash for a week or two. Ummmm, I could probably pull apart my Carb this weekend, figure out what's in it. Then get what ever parts are needed next week and maybe get out to do it next weekend.

Yes, it's popping on deceleration. The one time I had the plug out it was black as coal and dry if I remember right.

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

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Khris and Ron,

Would you be interested in having another TT along. I have a 99 WZ and would like to work on some jetting myself. Sounds like it could be alot of fun. I am very mechanical, have changed my needle to a YZ, along with some minor jetting changes. I just need some hands on instruction on what everything does and how it affects the carb. Let me know if I can tag along. If so I also would like to know what needles/jets to get. Thanks.

Kirk

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I definately don't have any problem with it but then again I'm not the professor, I'm just the student. I guess we need to agree on an area. Where is Lakewood at? I'm gonig to attempt to pull my carb apart this weekend to see what's in there. Then speak with Ron about what I have and what I need. I'm available pretty much any Sat/Sun except for Oct 27/28 cause I'm going to ride, not wrench. Like I said though, a local track, desert, or secret spot is good with me. I'm itching to go to Ocotillo Wells and I'm trying to get Ron out there also!!!

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

Animated_Tach.gif

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Alright! It's jetting party in the desert.

Professor? No, you have me confused with JD or Taffy. I'll get you in the ballpark, but we're staying away from drilling jets, exotic needles, and bk mods.

Have you guys studied up on jetting here on tt? Mucho info regarding jet sizes. Once we find out what your current jet sizes are and what it's doing wrong we can get a handle on it.

Things we need to know before getting started:

Current jetting

What's wrong (popping, fouling, flat spots…)

Elevation of riding areas.

What have you done so far? Airbox lid? What exhaust are you running?

Lakewood is not too far north of where I am. Where do you ride Kirk?

Khris, try using lower-case img's in your signature. smile.gif

------------------

N 33'41.156" W117'59.749"

HelmetCam Videos

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I've done a lot of reading and think it'll make a lot more sense once I get the carb opened up. I've also heard the manual is really good so I'll have ti by my side. Chances are, I'll get it apart, figure out what's in it, get suggested changes, make the changes, and show up with it running great and ready to ride. As far as I know for me the popping on deceleration is the only noticable sign I have. My bike is stock motor wise and exhaust. Mine didn't come with a lid, it's a YZ. What else should I look for?

I changed the IMG to lowercase so we'll see if it works. I'm having fun with this posting pics. so now I'm just experimenting with them in different places. I've loaded up another board with pics in all of my threads to help describe what I'm talking about.

WAIT A SECOND!! The image didn't work the first time I posted this reply but then I edited some of the main text and now it's there. What's up with that?

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

Animated_Tach.gif

[This message has been edited by sirhk (edited October 10, 2001).]

[This message has been edited by sirhk (edited October 10, 2001).]

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Man do the BK mod while you got the darn things out! this is the BEST performance mod you can do to this carb, and it only takes 10 minutes to do it and since you guys are all getting together, just hit the local Home Depot first and get the parts....all 3 of your bikes can be done for less than 10 bucks in parts TOTAL. man you are blowing it by not doing this CRUCIAL mod...Do a search on BK mod, I wrote a novel step by step how to including part numbers from Home Depot for the springs and washers plus the drill/tap kit and the screws you need to do it! and I posted it here last month....also the parts you buy at Home Depot come in Bulk so there are enough to do like 5 or 6 bikes! DONT waste the opportunity!

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01' WR426,YZ timing,EMP #2,#48Pilot,#100PAJ,#175 Main,BK mod,Kouba T-Handle,YZ pipe, open airbox,Gray-Wire Pulled,K&N Filter, throttle stop mod,CA Street Legal,Pure SuperMotard 17 in. wheels, 15/46 gears,ProTaper bars,

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Sounds like a party! Lakewood is right just north of Long Beach. I ride at Glen Helen, Lake Elsinore and Comp Park for tracks, LEMP is my favorite for tracks. Hungry Valley and Beaumont for casual riding. I haven't hit the local mts. yet. Ocatillo wells I hear is an awesome place to ride. My bike specs are:

Air-box lid removed.

Throttle stop modified.

FMF Powercore IV, stock header

but want to go with the Dubach

Pipe/header.

YZ plastic/tank/seat.

I did the grey wire mod.

Octopus removed.

YZ timed.

Forks revalved, resprung.

Rear shock has a YZ spring.

Now about that BK mod. I have read up about it on TT. Sounds like it is awesome but how would me bike benefit?

What were the dates that you wanted to do this? I'll write more later with jetting specs, I gotta get to work.

Kirk

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Octillo wells is a great place to ride. i grew up riding out there. if you guys get a chance go to the mail box, also go to one way hill if you can ride a few hours. there is also an old stage coach station out there twards the bombing range just something to see. this is where the stage coach used to change the horses. lot of cool riding out there.

------------------

wr42601

yz timed now

some mods

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I've got the '99 YZ400 and from all the stuff I've read it sounds like I can't do the BK Mod. Also, that doesn't sound like something to do onsite. It sounds like something that should be done in the garage. I'm open for pretty much any Sat. except the 27th/28th cause I'm going to Ocotillo to actually ride, not wrench.

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

Animated_Tach.gif

[This message has been edited by sirhk (edited October 11, 2001).]

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Take along a copy of this 4-stroke graph. All the needle adjustments need to be evaluated using a direct comparison on the graph.

www.trailtech.net/jet_tech.htm

I usually recommend needle EMN#4 (EKN#3) as a starting point. EMM is richer 0-1/4 throttle and EMP is leaner 0-1/4. They add to your mid-range power. Compare to a stock needle and you will find it hard to go back.

Needles that start with D-- are fat at the tip and need bigger main jets by 2-3 steps than a EM- needle (175 -> 170 or 168). Get the needles from Sudco @1-800-998-3529 for about $8 each.

James

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TeamScream - You've talked me into the bk mod. I've looked at the pictures and it all makes sense. My '00 WR has been running so darn well that I've been afraid to touch it. It starts first kick hot or stone cold (no kidding), pulls hard from the bottom to the top, and had the original spark plug for a year and a half. The old "if it 'aint broke" theory.

When I was doing my jetting routine after I YZ timed the thing and installed a DSP exhaust , I did adjust the spray to miss the slide, but it is still spraying a loooooong time. Can't wait to loose the bog, although it does not bog at all unless you really wick it like a two stroke, and even then it's barely noticeable. Heck, what can go wrong?

Sorry Khris & Kirk, this won't work on your bikes. I'm gonna do this before we get together, so maybe it will give me something to tinker with on my bike when get out there.

James, Thanks for the charts. I'm sure they will help. While you're here, I'm gonna ask you the same question I'm sure you've already answered a thousand times. I'm curious about all the needle research you've done. As I've stated above, my bike runs real well and I've never bothered to tinker with needles.

Here is my info:

The usual (YZ timed, no lid, etc.), DSP exhaust, always a clean air filter, 180 main, 48 pilot, 2.2 turns out. Elevation Range & Average Temp: 3500 - 7000 feet at 75 degrees. I forget the clip position. I think #3.

She runs a little fat at 7000 + (duh), but I'm very happy with it as it sits. Stock needle and everything else.

If I change to a EMN#4 needle when I do the bk mod, what will I need to do with the main and pilot jets?

Thanks a ton!

------------------

N 33'41.156" W117'59.749"

HelmetCam Videos

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Tree Hugger,

I thought your fellow Oregon Hippies still had you out sitting in the trees protesting human progress? I wired up the tach to that Gizmo right behind the flux capacitor on the port side. I've noticed it's idling kinda wierd. I think I just need to adjust the fuel spray into the turbine which is most of the reason I'm asking for help with my jetting. tongue.gif

Ron,

Yeah, I wasn't thinking the BK mod or anything cause I was pretty sure it wasn't for my bike. Did you get that email? Which day were you saying sure to?

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

[This message has been edited by sirhk (edited October 11, 2001).]

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Hi pops. Did Khris just call you a hippy? shocked.gif

Khris, not SURE yet about the date. Really busy with work (sos). I was thinking maybe I could pick up Kirk and head down your way. My bike needs attention (read $$$) before I take her out. Still have to MAKE time for a little tlc.

I'll know in a few days what my schedule is for the next few weeks. I'm almost over the hump!

------------------

N 33'41.156" W117'59.749"

HelmetCam Videos

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No worries. I need time to get the parts and figure out what I got in there now. I'm just stoked you're gonna come check out my riding area!!

Kirk,

I'm assuming you've got the WR tank or something similar so we could connect a ton of short runs into one long run. If not no biggie, it's the type of area where you can easily haul ass back to the trucks to get gas.

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

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This hippy wants to know how a YZ hauls ass back to the trucks to get gas? Are you saying that a YZ uses no gas when it goes fast? If my bike runs out of gas, I have to haul it back or send a YZ to get some. Correct me if I am wrong, but I think YZ is Japanese for Tanker Truck.

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Well you see after going on a short 100+ mile short ride we're usually close enough to realize that, ahhhh hell I give up, you win!!!! blush.gif

------------------

Khris

"What's that?"

"It's a Yellow 99' YZ400!!"

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