Air Box Lid and Jetting

[kxjet]

Hey all. I've had my KDX200 for about 3 months now and I'm ready to start doing some mods. Air box lid is first since its free. I did some searching and found lots of ways to either mod or remove the lid, I have a different question. Will I need to re-jet once the lid is removed? I dont know if the increased air flow would cause any problems? Thanks for the help.

 

[KDXMAC]

jetting

i drilled holes in my airbox lid and found I didn't need to change the jetting at all. If your not sure do the mods then do a plug chop. I found the airbox mods worked best with boyseen power reeds more throttle responce and breathed better up top.

GOOD LUCK

 

[kxjet]

Well I just got back from a 40 mile ride. Mostly open desert and quad trails, and a couple of creek crossings. I lost my coolant reserve cap out there somewhere. Anyway, the bike is running fine. I can definately feel a bit more punch in the mid rpm range, but at the bottom it seems to be bogging down a bit. The bike also seems like it lost a little bit off the top. I am riding from about 1800ft to about 2200ft, so my stock jetting should be fine. I'll try the plug chop next weekend. :think:

 

[Rhodester]

If it's cold out your stock jetting may be in the ball park. I developed a hesitation and/or flat spot (depending on jetting) in the low end when wicking it under a load with the lid removed. No amount of jetting, cylinder base milling/compression raising, KIPS cleaning, reed changing, pipe changing, silencer changing, and timing changing would completely fix the problem until I put the lid back on (without the snorkel). If you want a more detailed explanation I can provide it. Good luck.

 

[trailryder]

Rhodester- please tell me you didn't do all those mods to try to get rid of that "flat spot" All you has to do was clean up the bottom end jetting.You did try that first ???? Don't get me wrong, I had a ktm that I got so sick of trying to jet correctly...hell. I would have been happy to keep plugs from fouling !!!! that I sold it and retired from riding for a while......

 

[kxjet]

Now that you mention it it was about 65deg outside when I left, and about 50deg when I got back. When I was riding back the bike did improve more and more as the temps fell. Could you explain what yours was doing? Oh and another thing. Why is it that everyone else can get their wheel up in 1st through 4th gear, and on solid ground I can only do it in 1st? No matter how hard I try.

 

[mnnthbx]

i drilled holes in my airbox lid and found I didn't need to change the jetting at all

Thats because it's jetted so poorly stock, when you went from one situation of poor jetting to another, so it felt nearly the same. Take time to work on it. Well worth your effort. I thought I had mine right for nearly a year, then thought I'd try some more, and, BAM!. There are huge improvements to be made w/ the brass.

 

[John Harris]

At 2000 feet at any temperature above zero F with stock jetting you will be rich, rich. Leave the lid off and start leaning the jets and you will get that smile on your face! Cheers John

 

[kxjet]

Could this be the reason why many other KDX owners can bring their front tire up in 3rd and sometimes 4th, when I can only bring it up in 1st? Well I went ahead and did it. Since I will be re-jetting the bike, I orderd the FMF torque pipe and Tcore2 silencer. Should I get the reeds now too?

 

[Roland C]

Try to restrain yourself to one mod at a time, otherwise you won't know what helped a lot and what helped a little. The Delta Force II reed cage has gotten good reviews and may be a good next step after the pipe. The DFIII just came out and has gotten some good reviews so far. You're stock jetting (probably 160 main and 48 pilot ??) is likely quite rich. I'm running a 155 main and a 45 pilot and that seems to be pretty good (at about 5000 feet). If you don't get the jetting right, you won't fully enjoy the new pipe. Even a new pipe will dog a little if you don't have the jetting on. Hope that helps. Also, don't neglect suspension. All that power won't make you much faster if the bike doesn't handle well. Stock suspension is set up for a 135 lb rider in the front and a 180 lb rider in the rear. Don't ask me why Kawasaki does that, but you'll likely want to put stiffer springs in the forks (at bare minimum). Cheers and congrats on the new ride!

 

[Rhodester]

trailryder, I carefully went through the following jetting setups over about a year and a half and meticulously logged the results. Main jets: 148, 150, 152, 155, 158, 160, 162, 165, 168. Needles: R1174K, R1173N, BEQ, BEN, BGQ, CEP, CEL, CEK, CEJ, DCQ, DEK, DEJ (averaged 3 clip position tests with each needle). Pilots: 38, 40, 42, 45, 48. Throttle valves (slides): #5, #6, #7. Please tell me what I missed.

 

[Braahp]

Why is it that everyone else can get their wheel up in 1st through 4th gear, and on solid ground I can only do it in 1st? No matter how hard I try.

Don't worry.
Everyone else is full of it...or they are yanking like crazy and leaning ALL the way back My KDX is jetted perfectly.... geared way down......runs like a scalded dog. 2nd gear.....a little....3rd gear no way. 4th gear......you got to be kidding! :ride:

 

[wanaride]

Yeah, I've read so many "I can wheelie in any gear without dumping the clutch, you can too when you fix your jetting" posts my head can spin.

My jetting is probably not spot on but I think it's close, and there is NO WAY the front of my 200 will loft when I wick the throttle while moving slowly in 2nd gear. :|

No way, that is, unless I dump the clutch, then it will pop up with no problem, but since that feels like cheating, I don't get too excited about it. I've tried loads of pilots, mains, needles, clip positions, and air screw positions, and it just ain't happening! :pissed:

The only thing I haven't tried yet are #607 Boyesen reeds and the RB carb mod. Well, I guess losing 50lbs would help... :laugh:

Oh, by the way, they aren't kidding about spending time on your suspension. I'm still working on mine, but the improvements have already been noticeable and helpful.

 

[TheGrinch]

Here's what I did to mine:

With my stock 2000 model KDX 200 I have raised the clip on the needle one position to the second position from the top. I have changed the main jet to a 155 and the pilot jet to a 45.

I have also drilled 5 (1cm in diameter) holes in the back of the airbox lid and removed the snorkel.

 

[KAY DEE EXER]

Without sounding like a deckhead I can loft the front up in fourth. Not a controlled wheelie but with a yank on the bars at about the same time the P/V's open and she will loft for a few metres. When I ride next Ill try agian to be certain. Like I said Im not bragging or trying to prove anyone wrong, I just think its the timing of the yank...

 

[trailryder]

Rhodster- I'm at a loss if you did that much testing research,no one knows your bike better than you I'l say. Good luck. The best way I've found to get the front wheel off the ground in ANY gear is to add more stickers to the bike, I've said this before, were you not listening ????

 

[wanaride]

Sure, I can get the front wheel up if I rock the bike while yanking the handlebars and gunning the throttle. I can also get the front wheel up if I rev the engine and dump the clutch. I can also get the front wheel up when accelerating very hard in 2nd or 3rd gear.

My understanding, based on reading MANY posts, is that the front wheel should lift up with a simple roll of the throttle (in the lower gears) IF the jetting is "spot on". I guess this is the holy grail of jetting. :(

For those of you who are "there", wow, good job, must be nice! Maybe someday...

 

[mnnthbx]

......runs like a scalded dog. 2nd gear.....a little....3rd gear no way. 4th gear......you got to be kidding!

there is NO WAY the front of my 200 will loft when I wick the throttle while moving slowly in 2nd gear.

There are alot of factors here, and I'm not too sure all this wheelie talk means crap anyway, but..... my 200 lift the front end very easy in 2nd with no clutch or pull at all. Third gear very easy with a light pull only, (no clutch) and forth fairly well with a good pull, (still no clutch).

Thats no BS. It has a woods pipe, PC II, DFII, geared 13-50, 42, 156, mid clip.

Braahp, we're meeting at Good Times Kawi on topside rd. Sat. @ 8:00 for a wind rock trip if you have nothing going on.

 

[billc]

"they are full of it"

I'm with him on this one.

 

[John Cena]

Well I tried this on my 92 KDX 200 and I could only get it up from dead stop in 1st and 2nd and 3 with a little movement, 4 no way 5 nope nata 6 ha. Im using stock reeds and valve though. :cool: :ride:

 

[Rhodester]

trailryder, I had to run rich on the main and rich on the clip position to diminish the hesitation and turn it into a flat spot (with various jetting combinations). It was ONLY with the lid on (minus snorkel) that I could jet it crisper on the main and needle without a significant hesitation when I snapped the throttle to WOT when cruising just off idle. I'm currently running 42-DEK/3-152-AS 1 1/4 at 2800' and temperature in the 70s. I'll still on rare occasions get a hiccup-and-go when I wick it. With this jetting I would get a BIG hesitation with the lid off. I know each bike is a little bit different, but if anyone has the lid off and is getting a hesitation I'd highly recommend trying it with the lid back on to at least test this possibility. I spent a lot of time and $$ to ultimately find a cheap and simple cure.

 

[wanaride]

Gnarly pipe, 12/47 gearing, 155/42/1174-3 with AS in any position and any temperature you can imagine, the front wheel will NOT lift with a throttle wick on a slow 2nd gear crawl. (Stock reeds) I do have that slight hesitation down low, maybe I'm too lean there, Lord willing I'll tweak it some more once my left arm heals.

I never saw that rock under the leaves, but MAN, I did see that tree though, if only for a second... :ohmy:

 

[Roland C]

I've got a woods pipe (-35), 12/47 gearing, 155/45/1174-2 with AS about 1 turn out and my 200 runs great. First gear wheelie, no problem. Second gear, yeah, but not at low rpms. If I'm on the trail riding hard, the front will come up a bit in 3rd and 4th if I'm at the right spot in the powerband and have a little rock or root to pop it up. I don't think my bike could come close to looping in 3rd or above, though it would loop pretty easy in 2nd.

Wanaride - sounds like a nasty wreck. Hope you get back up riding soon!

 

[wanaride]

Sounds like our bikes are almost identically equipped, and your performance sounds like mine too. Yours may be a little peppier though, so I'll go up one on the pilot and lower the needle one position to try your jetting out.

Yes, it was a nasty spill, worst one I've had. Doc said no fractures, so that was a plus, but it will probably be several more weeks before I can ride again. :(

I learned a lesson though...when leaves cover the trail, SLOW DOWN! If you can't see under the leaves, you better slow down so you can better react when the unexpected happens. I crashed on the same down hill section I've taken dozens of times before without incident, all because I didn't see the rock under the leaves. I did see the tree though, but only for a second!

And if you don't have rad guards, get them! I have them, but after two hits to the left radiator, the guards need to be replaced.

 

[Roland C]

Hey Wanaride - I had a wreck very similar to yours. I was on a jeep trail that was mainly hardpack with lots of sharp jagged rock imbedded in the dirt. I was riding hard in fourth coming up on a roller and as I crested the roller I let off on the throttle for the downhill (effectively weighting the front). There were lots of trees and it was getting on in the evening and the light was mostly shaddow with some sun coming through here and there. I never saw the rock that threw my front wheel sideways. The bike made two or three good swaps before bucking me off. I was probably doing about 35-40mph at the time and did a superman onto the road on my side. I was pretty much hamburger from my right knee up my right side, armpit, and right forearm. The impact wasn't so bad, it was the sliding to a stop on that rocky road. I had motocross pants on which really saved my leg, but those jerseys don't have much protection. I've since gotten forearm guards.

On the jetting: I'm running a 45 pilot, I'm also at about 5000' elevation. I'm guessing NC is quite a bit lower. I would definitely suggest moving the needle clip one though, that really helped liven my low-midrange. I'm also running Boyesen reeds, airbox lid modified, uni air filter, and Steahly flywheel weight (really helps on the tight stuff). Let me know how it runs. Good luck!