going to be too lean???

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
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ridinredneck
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going to be too lean???

Post by ridinredneck »

i picked up a 2002 kdx 200 off of a fellow member. the bike has a rich condition. i have tried different needles and jets but cant get it to run clean. it sputters and blubbers from off idle till about half throttle or more. i ended up back with the stock needle with the clip on the very top, 38 pilot and 150 main with the air screw at 2 1/2 out. i tried the CEL needle and the bike wont even idle with it in. i even tried an NOZF i had from a ktm 200. better than the CEL but still way rich. im thinking i need a needle that is one step leaner than the stock one. but i really didnt expect to have to go this lean, especially this time of year. suggestions are very welcome if you have a different thought other than a leaner needle. some additional info you may need is: elevation-around 1000 ft. temp today was mid 50's. also wanted to add that the bike will start with one 1-2 kicks and idle without using the choke. another sign of too rich.
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skythrasher
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Re: going to be too lean???

Post by skythrasher »

Go through the easy stuff first and if you need a leaner needle so be it. Bikes can be different animals and just because one responds well to a certain tune doesn't mean mine or your will do the same.

1. Proper float height
2. New or freshly cleaned air filter
3. New plug
4. Disassemble a clean carb and jets or replace with new jets
5. Start with stock jetting or jetting recommended by manual for your elevation.
6. Air screw 1 1/2 turns out
7. Set idle adjustment so that there is a small amount of lift on the slide when looking down the bore.1/16-1/32 inch
8. Start bike and get it good and warm
9. Adjust air screw for maximum idle speed the turn it back 1/8 turn (this could be either direction, whichever results in highest idle.
10. Count how many turns out the air screw is, if less than one go larger on pilot, more than two go smaller on pilot.
11. The main jet can only be accurately determined by plug chop method with the tools and equipment available to us mortals. Although you only run solely on the main at WOT it can and will have some affect at other throttle positions.
12. The stock needle should get you close enough to ride and not foul plugs as long as the main and pilot are correct or fairly close. Once you have the main and pilot established you can ride the bike and decide where in the throttle range it is lean or fat. At this point you can refer to the Keihin needle chart to select which needle will cure that condition. Needle changes can be as much for rider preference as fuel air tuning. What I like, you may not, and vice versa.
Last edited by skythrasher on 08:18 pm Feb 01 2014, edited 1 time in total.
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ridinredneck
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going to be too lean???

Post by ridinredneck »

thanks. but i think number 10 is backwards. turning the screw out leans it. so if its more than two turns out i need a smaller pilot not bigger, correct? and it runs like crap with the stock jetting and needle placement. plus it drools all over the place. it has a new filter and plug. float height is correct and carb is clean. i have some experience with jetting but wanted other opinions as why it needs to be so lean. didnt know if it may be normal for the kdx.
ridinredneck
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going to be too lean???

Post by ridinredneck »

it seems like if there were another notch or two on top of the stock needle i could get it right. so maybe an AJP needle will cure it. same diameter but a lil longer. taper is different but i might be able to compensate by changing the main jet
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skythrasher
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going to be too lean???

Post by skythrasher »

ridinredneck wrote:thanks. but i think number 10 is backwards. turning the screw out leans it. so if its more than two turns out i need a smaller pilot not bigger, correct? and it runs like crap with the stock jetting and needle placement. plus it drools all over the place. it has a new filter and plug. float height is correct and carb is clean. i have some experience with jetting but wanted other opinions as why it needs to be so lean. didnt know if it may be normal for the kdx.
Yes I have it typed backwards, if you turn it out you are adding air so you would want less fuel so that would mean smaller pilot.

Even with my sub-par typing skills my fingers can still out run my brain.

And you may be correct on the main jet. I would try a larger jet and see if that makes the difference. If you go to a needle change you have to determine what you are trying to change. The Keihin chart is very helpful for this. If the problem is one area it may be taper, if all over maybe total diameter.
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ridinredneck
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going to be too lean???

Post by ridinredneck »

yea i have been studying that chart for a while now. i believe that the AJP needle might be what i need. almost the same diameter but a lil longer. so it would be like having extra grooves on the stock needle. the problem area is off idle to half throttle. i know the taper is different but i might be able to compensate for that. and i know what you mean by fingers outrunning your brain. happens to me all the time. lol. BTW thanks for your help
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skythrasher
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Re: going to be too lean???

Post by skythrasher »

If memory serves me correctly the stock needle figures out to a BGN or BGP so that may work for you. My 01 is running a little fat (on purpose) with the stock needle and I cant quite remember what jets. I rum Amsoil Interceptor at 50:1 and she spooges just a little but not bad. She cleans off nice on the main. I like mine a little fat on the bottom and firm and crisp on top.LOL
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ridinredneck
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going to be too lean???

Post by ridinredneck »

BGQ is what equals the stock needle. forgot to mention i run 32:1 ratio. i think im gonna order the AJP needle and see how it does. keep yer fingers crossed for me. lol
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going to be too lean???

Post by Actionman »

He added an fmf gnarly pipe; how does that affect jetting? When I had the bike it was running pretty good, but I had the same concerns about the needle that he does. I could never figure out how you guys could run 42 or 45 pilots and mine needed a 38. The only time I ever had the overall blubbering was when my pilot was clogged and I'm pretty sure he's checked that. As to float height: I used a float tool to set the fuel line inside the carb to be 1-2mm below where the bowl meets the body. I also put a new jet block gasket in it as well and a new air filter. Crank seals were good as well. That's all the info I can add to the situation.
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ridinredneck
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Re: going to be too lean???

Post by ridinredneck »

well i have an update. i ended up with a CGQ needle in the 4th clip pos. and a 38 pilot. cant remember right off where i have the a/s set. i get a very, very slight hesitation in neutral when i whack the throttle open as fast as i can. might step up to a 40 pilot and try it. but for now its a lot stronger and cleaner. no pinging or hanging idle. next step is removing the KIPS spring and ball. gonna get back to back rides with it in and out. hopefully get a little quicker hit from it being out. i do have a question on that though. do i remove the spring AND the ball or just one of them?
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