KDXRIDER.NET

Can you tell by looking at the plug after a ride??

I try to run my bike mostly in the medium to high rev range to avoid fouling plugs. I just took these pictures after a half hour ride.

I heard they should be tan but looks more chocolate..?? I am running 40:1 with an FMF gold pipe and silencer. Brand new top end plating and piston with stock jetting I believe.

A kdx fouling plugs? Never fouled a plug on mine.

Sent from my XT907 using Tapatalk

I fouled one last summer. Well not me, but a friend who was riding it and not using the powerband properly maybe? I might have been running 32:1 then

looks pretty good, but if you're running stock jetting then chances are you're a tad rich on the pilot and main circuits. whats your elevation level?

Elevation is 70–110 m (230–360 ft) in Kingston, Ont. The bike has some symptoms of rich jetting such as slightly slow response in the low rpm(as in from a near stand still) and some slight hesitation and crackling. I also have my air screw a 1/4 turn rich which I forgot to adjust today.

Turning out the screw is just a bandaid fix though. My bike needs new clean jets anyways, mine are dulled out and probably a little corroded. What size main and pilot would you recommend for my current set up with the FMF pipe? I don't even remember the stock sizes

http://www.jetsrus.com/a_jet_kit_dirt/k ... 8_2006.htm

Also, are there any differences between genuine keihin and OEM equivalent? Best to go with genuine?

Edit: I did a bit of research and found the stock sizes 48 and 158. Should I drop the pilot to 45 or 42, and just leave the main or buy a new one equivalent size? If I go up one or two sizes on the main jet will I gain any top end power?

oh my. your plug looks way better than mine did at stock jetting. whatever was in my kdx when I got it, pretty much unmolested, was PIG F'n rich, totally rubbish. Now I have on my 93 kdx, FMF pipe and sparky, RAD valve, no-toil filter, hacked air box and 40:1 honda hp2. My plug will last roughly 30 hours with 150/42 jets. 1 1/4 out on the air screw. stock needle, 2 clicks up. Hope that helps a bit. I went with keihin parts, because they are cheap and available, and I'm tired of dicking with crappy off brand parts.

Parameters
I ride from 0ft elevation to ~4k tops
I hate cold (anything under 40F) and I hate hot (85F and up) mainly because I have to pull the carb apart to change jets :)

FMF actually has a model specific recommendation for jetting with their pipes

http://www.fmfracing.com/RiderSupport/JettingCenter

Looks like 45-48 on the pilot and 152-158 on the main.

I'm going to try a 45/155

looks grey to me what plug are you using?it looks too hot! jetting is lean or timing is too advanced.Hard to tell from the pictures but it looks like small aluminium globs on the porceline and the ground strap is grey all the way to the shell.

Too hot? Pretty sure if it was too hot the plug would be white...

Alminum globs? Whatcha talkin bout Willis

Plug is champion, they didn't have the NGK at the store

it looks grey to me also. But unless a plug is way too light colored or way too dark colored I pay no attention to it at all. Not because I'm some KDX riding hillbilly but because I have lots of experience at jetting and I just go by how it runs throughout the RPM range, which is what the experts do. They don't go by plug color. Color has more to do with gas additives and oil used.
rich- sounds "congested", can sputter, runs better uphill and worse downhill
lean- sounds hollow, runs weaker, runs better downhill and worse uphill
Test at all three throttle ranges- 0- 1/3, 1/3-2/3, 2/3 to wide open
Note also how it accelerates when you open the throttle.

There is quite a bit of hesitation and crackling through the low to middle of the power band when giving it throttle. Once kips kicks in, it's pretty smooth sailing. Does that sound like rich pilot, or both? Should have gone smaller than a 45?

Am I missing something here? Why don't you just spend an hour or three and jet your bike properly? The following link from this site is an excellent resource:

http://www.kdxrider.net/forums/viewtopi ... 105&t=1156

Good luck!

get the thicker OEM needle, already

go down one on pilot and 2 on main

Get an NGK plug if you want anyone else on the planet to guess at temp range.

I went down 1 on each for a 45/155

What size needle are you talking about? There is about 100 listed on jetsrus

http://www.jetsrus.com/a_jets_by_carbur ... 27-48.html

kawasaki.com, OWNER INFO, PARTS DIAGRAMS... it is one step thicker,,, the one Jeff Fredette recommends.


Which pipe do you have??

I was at 45/150


Be aware that 1990 - 1994 is 150 main, not 158 as 1989

Thanks, I stated earlier that it has an FMF gold pipe

There is a 158 in there now. In fact it has all stock jetting 158/48. It is a 1990 model after checking the 10th digit of the VIN ...it left the factory or imported 09/89 so at first I did think it was E1.

Jeff recommends the same as the FMF website. A 152-158 and 45-48 and 1173 needle. So I will be right in the middle with the 155/45.

150 main seems like a big step down but I see they did make that change in 1990+ diagrams. Would rather be too rich than too lean

Looks like R1170N on the needle, with 5 other options(A~D) going up in number size. I assume 1172 is standard and Fredette recommends the 1173?

R1173N is one step leaner by way of being thicker.

When I jetted mine, it ran great at:

45 pilot
stock slide
R1173N needle
150 main

73 degrees, 1000 ft elevation

FMF pipe, FMF spark arrestor, Twin Air filter, airbox lid cut halfway

The thicker needle helped in the 1/8 - 1/4 throttle range.

So the stock needle is not Keihin, but made by Kawasaki? Kaw r1173n needle translates to Keihin N427-48 BGP/017-426 in the conversion table and I get this:

http://www.jetsrus.com/individual_parts/017_426_su.html

$20 to ship a $6 needle to Ontario. Any other place I can check prices? I got the Keihin jets on ebay together for the price it would cost just to ship them with jetrus

Keihin makes them for Kawasaki. You can buy the comparable one.

You guys get screwed on shipping.

I bought mine from Jeff Fredette years ago.

I have recently bought jets from Rocky Mountain. Maybe they ship to Canada.

Hmm not seeing anything in the way of needles on RM. Although they do have good prices on jets