ANOTHER jetting question!

[NM_KDX200]

1996 KDX200, FMF Rev, FMF ISDE silencer, airbox lid cut in 1/2. Altitude 6,000'. Main 150, pilot 38. Bike ran good in acceleration but blubbered a little at steady throttle (.ie fire road cruising). I dropped the stock needle from 4th notch to 5th notch and it ran much cleaner at steady throttle. All's well here at 6,000' but I don't like running at the end of my adjustment on the needle. I'm going riding at 8,000-10,000' before the summer's over and want some adjustment.

So- when I go to higher altitude, do you think I'll just go leaner on the main, or should I go ahead and get a leaner needle now and run it in the middle clip position? What needle is leaner than the stock 1174? (1173?)

BTW- I bought a KX125 a few weeks ago. It's a lot of fun on the track, but I rode the KDX again yesterday and ya know what? It's still a lot of fun, too, esp. on trails, rocks, mud, off-cambers, water crossings, etc...

 

[Green Hornet]

I would find the correct Main and then use the needle as an adjustement, along with the air screw

 

[G. Gearloose]

Sounds like a perfect application for James Dean's jetting calculator.

 

[Rhodester]

I would find the correct needle and clip position and change the main jet as per elevation and temp changes. Once my needle was dialed in I never needed to change it again. It took me 13 needles to dial it in, btw. Only under extreme condition changes would I need to change my pilot. The air screw should suffice (in my case-- always). The main jet is designed for quick and easy changes for a reason. That's the one that you need to deal with for the VAST majority of temp and elevation adjustments. A 150 main at 6000 feet is a tad on the rich side for me. With my setup ('95 200H, FMF-35, "Q", RAD valve, DEK/3 needle, 42 pilot, #7 slide) I need a 148 main at 6000' and a 146 over 8000'. With the stock needle you may be pretty close at 6000'. BTW, the clip positions go from the top down. When you say that you dropped the needle from #4 to #5 it doesn't compute in my brain...it sounds like you raised the needle to me.

 

[John Harris]

I think I understand that you have the clip in the top position and the needle is all the way down. Leave it there and change your main jet. The 38 should be good to 12,000 feet with air screw adjustments. I suspect that you will need a 146 up high like Rhodester suggested. You will wonder where the power went at the high altitudes. Great fun--Cheers John

 

[NM_KDX200]

A 150 main at 6000 feet is a tad on the rich side for me.

Agree- it is a little rich. [LATER]- well, I was wrong! I DO have a 148 in the bike right now....

With my setup ('95 200H, FMF-35, "Q", RAD valve, DEK/3 needle, 42 pilot, #7 slide) I need a 148 main at 6000' and a 146 over 8000'. With the stock needle you may be pretty close at 6000'.

Just what I was looking for- I'll give your specs a shot. [LATER]- what's your airbox mod? I have the top of mine cut 1/2 off and just for fun, I duct-taped it back up so that there's only a 1.5" opening in the back. It sure doesn't seem to run worse, and in fact, I think it pulls harder off the bottom. Off to search for "airbox"....

BTW, the clip positions go from the top down. When you say that you dropped the needle from #4 to #5 it doesn't compute in my brain...it sounds like you raised the needle to me.

You're right- my brain wasn't cooperating. What I meant was I RAISED the clip and thus DROPPED the needle. In other words, the needle is as lean as it can go and I'm in the #1 position. That's why I was thinking I should do some more work so as to get the clip on a different position, giving me some adjustability again. What you're telling me, and what I was thinking myself, is to reduce the main jet another size.

Like I said earlier, the bike is running very good now, I'm just looking to see if I can get "better" and also to learn some more about how it reacts to jetting changes, so I'll know what to do when I go up to the woods.

You will wonder where the power went at the high altitudes.

I hear ya. When I drop down to Amarillo TX or even Pueblo CO, both at 4,000' I always nearly loop the bike once or twice before I get used to the extra power. I can't even imagine what sea level must be like! :yikes: You guys must have some POWER available!

 

[Brent L]

detailed questions on jetting

I would find the correct needle and clip position and change the main jet as per elevation and temp changes. Once my needle was dialed in I never needed to change it again. It took me 13 needles to dial it in, btw. Only under extreme condition changes would I need to change my pilot. The air screw should suffice (in my case-- always). The main jet is designed for quick and easy changes for a reason. That's the one that you need to deal with for the VAST majority of temp and elevation adjustments. A 150 main at 6000 feet is a tad on the rich side for me. With my setup ('95 200H, FMF-35, "Q", RAD valve, DEK/3 needle, 42 pilot, #7 slide) I need a 148 main at 6000' and a 146 over 8000'. With the stock needle you may be pretty close at 6000'. BTW, the clip positions go from the top down. When you say that you dropped the needle from #4 to #5 it doesn't compute in my brain...it sounds like you raised the needle to me.

I also have 95 200H and ride between 4000 to 9000 feet in California so your recommendations should apply somewhat. But what are "Q" and DEK/3 needle? Thx, Brent L

 

[Rhodester]

Brent, the 'Q' is an FMF quiet silencer. The 'DEK' reflects the needle I'm using from the Keihin factory numbering system for their needles. The '/3' designates the clip position I'm using...the third groove down from the top. Go to sudco.com for some more detail on the carb breakdown and the needle sizing and profile types. Canadian Dave's link at the top of the forum will give you a breakdown on how the Kawasaki needle part numbers relate to the Keihin needle part numbers. Also, don't forget that there is a relationship between the slide (throttle valve) and the needle you choose to run. My DEK would be too rich if I was running the stock #5 slide. A DEM would be a better choice with the stock slide.