Jetting 36mm carb EXC200? JD jet kit

[camchain]

I'm pretty green Re jetting, so I've had a big trawl through jetting threads. Made a few notes, but at this point I'd be real interested to know what setup others are using in their 200s. Plus to what extent richer changes usual for winter? Note this particular one is '07 36mm carb, earlier models had larger carb. I think they switched for more velocity = smoother lower end (?).

Bought a JD jet kit on shop suggestion, so owner's handbook jetting chart not totally applicable now.

In the JD kit:

Mains are 160,165,170,175
Seems a fair bit towards richer end of spectrum compared to stock chart, but sounds like a good idea to me especially with 14/48 low-geared 200 on faster gravel type sections. I tend to lag behind pace here for fear of a you-know-what)

Pilot is 38 - instructions suggest using this if running spark arrestor (hell - that still seems very lean).

Blue needle and Red needle. Haven't a clue how these relate to stock NOZ type needles. Have the feeling the two kit needles are maybe same size/taper but swapping between them offers 1/2 clip equivalent steps? Anyone know?

I'm keeping notes on changes and even taking thermometer along.

Brew is 45:1 Motul 800 - Currently on 42 pilot, 170 main, Blue needle 3rd clip. Air 1 1/2.

Float seemed a little high so dropped it a touch. Found KTM handbook float height instruction a bit vague. Anyone have a better way?

Hope I'm in the jetting ball park, maybe drop back to 45 pilot and some needle fiddling? Was pretty smokey first hour of running in new top end, cleaned up a lot now, but still some annoying black spooge at muffler (has had fresh repack). Intend to do a plug chop or two and quite keen to try some of this wet-line jetting at some point - when I can find a good place to do this stuff! How does where I'm at compare to others settings? How good are the owner's handbook jetting charts? Cheers.

[Reckless]

Well my 2c is jetting is done for the rider not by the book!

Mine for instance is not jetted perfectly but it goes as well as I can handle as a rider. If you take the plug out after you chop it off during a hot run its a bit wet around the outer with a copper colour inner. Which (to me) means it could be a bit leaner in both areas especially the low end. And it does produce a very small trail of stouge that doesn't quite run down or drip off the outside underneath of the muffler after a few hours riding.
But its how I like it, delivering smooth, fat power, at a much faster rate then I can handle, right through till it over revs! It still pulls ok off pipe as well! I believe the slight richness fattens the power and at my level helps my riding and keeps my reconditions wider apart! If I can ever out ride it or as I get better I'll have a play then

There are correct methods for getting it perfect Danger discribed them in another thread, you need a few brand new plugs and a good stretch of track. Do a search if you can find it, its very good, had pics and everything.

But a perfectly tuned bike may not actually be how you might prefer it??

[humai]

Your JD kit should have instructions and guidelines that will allow you to start in more or less the ballpark place, jetting wise.

My 03 200 has the 38mm PWK carb so my settings may not necessarily apply to your situation.

That range of mains you have looks about right. I run between 175 and 178 depending on where I am riding.

The standard setup for a KTM two-stroke with a Keihin PWK carb usually involves use of a "N0Z x" series of needle (Mine was N0ZG stock). These triple taper needles are notoriously rich and blubbery just off idle up to around 1/8th to a 1/4 throttle (depending on clip position), contributing to the typical spoogy KTM exhaust condition. This is especially evident when running the #6 cutaway slide that the KTM two strokes ran in 2000 - 2002 or so. Mine is a #6.5 slide, which is slightly leaner just off idle than the #6.


The needles supplied in your kit should greatly improve this situation.

FWIW, I am now running an N3CH needle (OEM Yamaha YZ250 needle), which has cleaned up the low throttle behaviour dramatically.

I don't know what instructions normally come with a JD kit but, judging by the www.jdjetting.com site, James Dean is a good engineer with meticulous attention to detail on this subject. If the supplied instructions don't cover off what you want to know, drop him a line. I'd say the needles and jet range supplied in the kit should be pretty close to the mark.

BTW, with float level setting, there is, somewhere in existence, a precise, exact float level but as a general rule of thumb, the needle valve should shut off when the moulding seams on the plastic float itself are roughly level - that is, roughly parallel with the face on the carb body that the floatbowl mates up against.

Edited to correct factual data

[Danger]

Interesting subject, I've used JD needles in the RM250 but not in the KTM200 and like humai my 200 has a different carb so my settings would not apply. I'm surprised at the leanness of the mains humai is running and the N3CH needle must be an interesting profile.

When you change the profile of the needle the main required also changes because you don't want either the main or the needle to restrict the engine from getting enough fuel. This is a common mistake and a lean main can make the rich needle position feel correct and its why I tune the needle without running a main. Then tune the main to supply the correct fuel for full throttle operation.
I run a CEK straight taper needle in my 02 200, 6.5 slide and a 185 main in summer and a 188 main in winter. Big difference huh? If I ran a 165 I would quickly starve the engine of fuel resulting in a burnt piston. The CEK straight taper needle provides a smooth electric type power band with no jetting related hit. It is a fat needle in profile in comparison to the NOZ series needles. There are other straight taper that will provide more hit but if I want more power I just open the throttle more, this way I control the bike rather than the power controlling me.
Because the CEK is in my bike I can't mic it up but I have the JD needles here in front of me and a CEJ. I cannot confirm but have heard that the JD needles are the same for all applications. If that is correct I can't see how they can possibly be optimal for all applications. I know I could never get them to work well in my RM250, it was always lean somewhere in the range. The '05 RM250 changed to a 7.0 slide, the instructions included applied to the earlier 6.5 slide, when I brought this up with JD he conceded that the earlier settings would not necessarily work.
So persevering with the JD needles through out a summer and a winter and continually making changes I ended up going back to either the stock NECH or the NEDH needles depending on season. Things are dialed in now and the power is much stronger than with the too lean JD needles.
But they may be good for your bike and an improvement over the NOZ series triple taper needles.
If I mic up the JD needles the blue needle is richer than the red needle from the get go, but then the tapers are the same. So only the bottom end is richer using the blue needle instead of the red. Being summer you might want to run the red needle, clip position to be determined, start in the middle would be my suggestion and tune from there.
It appears from the profile of the needles I have that the JD needles should be leaner of the bottom, leaner through the middle of the taper and leaner at the end of the taper than the NOZ needles. This would indicate that you will need to go richer on the main in comparison to the NOZ series needles and as with my straight taper needles that I use.
Now your JD needles might be different to the JD needles I have, but if they are the same as I have heard (and it might be the grind through the middle of the taper that differs) then hopefully what I have added gives you food for thought.

[humai]

I run a CEK straight taper needle in my 02 200, 6.5 slide and a 185 main in summer and a 188 main in winter. Big difference huh?

Being a straight taper, your CEK is probably considerably "fatter" and consquently leaner at full throttle than a triple taper like the NOZ, hence the need for a larger main. I found when using the "C series" brass Sudco needles over the NOZ needles that I had to increase the main 2-3 sizes.

A 188 does seem extraordinarily rich though. My 200 came with a 180 stock. What air filter / air filter treatment do you use?

Edited to correct factual data

[Danger]

Exactly, I think I said that.
I use Motorex filter oil and a filter skin. It wasn't until I used a 190 main that things got to rich.
Funny thing is I run a leaner pilot than most.

[humai]

Whoa!! - I screwed up - I just went up to the shed to double check my settings and bugger me, I'd got it mixed up with another bike I do jetting on. That'll teach me to rely on memory. I've gone back in the thread and corrected the erroneous numbers.

I'm using a 178 main and go down to a 175 when the altitude is about 2000 feet - the bike came with a 180 stock. With a straight taper, this should be in the 180s somewhere. My apologies to all for the conflicting info.

Your JD mains supplied in the kit seem lean compared to the above but the smaller carb diameter and consequent higher airspeed may explain some of the difference.

[Danger]

That makes more sense.
My understanding is that the new smaller carb does run leaner mains but I have no practical experience jetting one. I know the power seems softer than the earlier models like my bike. Sheesh next thing they'll be putting the mangina starts on the things!

[dammad1]

That makes more sense.
My understanding is that the new smaller carb does run leaner mains but I have no practical experience jetting one. I know the power seems softer than the earlier models like my bike. Sheesh next thing they'll be putting the mangina starts on the things!

Lets hope so

[camchain]

Re muffler drool. Cheers Reckless. Exactly the type of extra comparison info I was after. Mine left a short trickle out of muffler yesterday so guess I have some safe room to move. I'm with you on staying on the rich side for safety and good fattish power delivery. Can't see much gain in jetting super crispy and risking super crispy engine. But not keen on gooey muffler packing or carboned up engine either. Want to try some leaner settings - just extremely wary about going too far and screwing up. How far can you go safely? Not intending to do this but for instance, could summer jetting cause a seize in winter?

With plugs being $30 a pop, I want to get to a good setup quickly, so only intend to use chop & wet line to confirm and maybe do some tweaking either way.
Have plucked & saved plenty of general jetting info from other threads but just seems like I could spend a lot of time trying different combinations. Especially if lacking solid experience/knowledge to feel the differences. Hence figuring I could do with some more model-specific ideas/info.

When doing a plug chop or wet-line test, my impression is that it could be useful to try and find a steep hill to get some load on the engine. Wouldn't having the thing revving it's guts out with no load give you a bit of a false read - not to mention seems like being bloody hard on the engine? What about dragging the brakes, would that be of any use?

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Thanks for that humai, especially the needle info. Might also help explain the seemingly very lean #38 pilot in the kit. May give the 38 a quick try just for comparison (after I sort my floppy power valve issue out). On KTMtalk it seems others are using a variety of non-standard needles, and needles seem to offer more in the way of subtlety with finer tuning than jets do? Was told the JD needles were multi-taper but they look straight to me.

This is my second JD kit, I put a one in the KLX300 and it really helped to wake the thing up on the bottom end. The instructions were a bit vague in both kits but this one basically said start at max richest and work from there.

My carb has a #7 slide. Might just be in balance being smaller carb, or maybe to lean the bottom end a bit more than previous models? Interesting that the owner's handbook says replace slide at 100hrs. At $400+ - not bloody likely. Can't see how a little bit of slide wear could have much affect anyway?

I think I should take another look at that float level. No 60 deg protractor so just propped up handbook and tipped carb to line up with angle in photo! Kind of hard to pick the exact point when float valve is seating. Had it apart and valve/seat look good though.

-----Uh Oh. While pondering Reckless and Humai posts, then having a bit of a type, more knowledge since has been dispensed.------

[noobi]

Plugs for $30?
that cant be right, are you buying the EIX iridium racing plugs or something?
When you do the jetting off the plug reading use the $6 dollar ones instead, I didn't notice much difference between the two plug types

[Reckless]

Re muffler drool. Cheers Reckless. Exactly the type of extra comparison info I was after. Mine left a short trickle out of muffler yesterday so guess I have some safe room to move. I'm with you on staying on the rich side for safety and good fattish power delivery. Can't see much gain in jetting super crispy and risking super crispy engine. But not keen on gooey muffler packing or carboned up engine either. Want to try some leaner settings - just extremely wary about going too far and screwing up. How far can you go safely? Not intending to do this but for instance, could summer jetting cause a seize in winter?

I'd better qualify my comments a bit I tend to tune on the rich side because pretty much, I can't ride the thing like Danger. Secondly I actually shouldn't really try and read a used plug, the proper method is the new plug/plug chop method. In all my karting days a slightly richer set up gave a fatter, better power delivery etc. This showed up on the Laptop when we did the Data acquisition. But we also didn't use the low range like you guys do either!

Just as an aside ! I was pitting for my mate racing classics at Puky, he pulled his plugs in his 140HP Z900 and they where grey/white. We took the plug to Robert Taylor as Sean didn't want to muck around with it just on my say so alone. We ended up going a quite a few main jet sizes richer (white plugs scare me) and he said he lost nothing flat out down the straight but it felt much more solid out of corners. So richer even has an effect on the feel of a 4 stroke engine. I've had many an engine on the dyno tuning for the max curves, fine tuning carbs and going 60:1 in fuel etc. The dyno always said that was the best power output. But we always came back to 25:1 (in the Kart) with it a bit smoky during the pre-race starts etc. Every test Ive ever read more oil = more horse power (to a point). It simply delivered its power better and lost nothing flat out?

I'd really like one day to get Danger to have ago at tuning mine just to see how it feels. I know how to do it, but a lot of the tuning is in the seat of the pants of the tuner. Probably find out for a bike, its better! But gonna get him to do the suspenders first, all the power in the world is no good with the wrong springs in! I don't need anymore power till my riding technique is better! The way mine is, its quite forgiving so its OK for me. Its way not rich enough for carbon to be a problem. This new bike has helped the learning curve gonna try and do over a hundred hours this year if the old body holds up!
Find that thread Danger did or pm me your email address and I'll send you the copy and paste of it I did.

With plugs being $30 a pop.

Surly you could use the $8 BR8es ones instead of the expensive ones for this?? I had the first plug fail in years at Xmas and bought a cheapo BR8es (they didn't have any flash ones in Whitianga) it goes absolutly fine!

[camchain]

Interesting alright Danger. Thanks for the info, much appreciated. Some of that food for thought may lead to a little indigestion though, having shelled out for the JD kit.

That's a good heads up re needle clips/main jet, very relevant to my situation.

I read that part in earlier thread about your tuning without a main but didn't copy it into my notes 'cause I didn't understand it! How does the bike even run?

Was trying to avoid overcomplicating this but the following info now seems relevant re needles: The first two JD kits supplied were wrong. First kit was for 38mm carb, second kit was for 36mm carb but for 250cc. Was told 250 kit would be fine for my bike, right size carb etc.
I wasn't convinced so emailed JD who said jets were different in 250 kit (250 had some richer mains, up to 185 I think, and no pilot), blue needle was identical, but 200 red needle appareently slightly RICHER than one in 250 kit. - Quote JD: "The leaner needle (Red marked) is not the same. We found that the Red needle was leaner than what most EXC200 riders would want and we developed a Red needle that was not as lean." Unquote.

I guess JD could have made a mistake on that (ie red 200 leaner not richer) but doesn't seem likely, I just found it very odd that red 200 needle would be richer than 250. Seems to indicate they do optimise needles to some extent for each bike though? Didn't want email JD back without having a dig around first.

Very surprised at your small summer/winter changes danger. Just shows the whole thing can depend a lot on how well the main relates to needle. My take is it would seem to indicate that your jetting is very accurate?

Your lack of success with the JD needles for your RM is a bit discouraging. I couldn't compare my JD needles to standard as I only had the crazy NOZI needle that came with bike. Now thinking maybe I should get a standard NOZF just to compare, even if I only measure it to confirm if the JD needles I have are leaner all the way.

I'm guessing that when JD brings out a new kit they must make a series of similar needles in small progressions, then dyno test and pick the best one (or rather two). But how do you dyno test for altitude and temp/humidity though?

---Don't know if a mangina start is really needed but personally I'd like a kicker that doesn't start with your knee up near your jaw - and end shortly after with foot painfully slipping off like it did yesterday.
Cough, Ahem - My '07 delivers a very manly jolt when power valve snaps fully open suddenly---

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Plugs: Thanks guys. Just double checked and price was $22 for BR8E'G', is BR8E'S' the real plain jane? Initially I wanted Iridium but that was much dearer still. Liking the sound of cheaper plugs for testing.

S'alright Reckless, just very good info to chew over and it does help a great deal to get ideas from different sources. Believe me - I really appreciate it, and pretty sure I know where you're coming from. I promise I won't slag anyone off if when I pull the jug next time, I need to chisel a quarter inch of carbon off the piston!
Hell that's a lot of pep out of a Z900. I remember when the CBX 6 came out in '78 - Just over 100hp was a big deal.

P.S. Don't remind me about suspension. I thought I'd be getting onto that shortly, but money tree has no leaves.

Thanks again all (and to humai for going to shed to check!).

[tommorth]

this may be handy if looking at sudco needles
http://www.sudco.com/vol33/135-136.pdf

Ive got the older 38mm carb carbon reeds and a reed spacer
#6 slide 180 main, ddj middle clip and a 40 pilot but its not perfect mixing tts at 32:1

[Reckless]

Cham,
Br8es is the basic. I think two cost me $16 bucks retail from a mower shop in Whitianga at peak Xmas buying. Was going to get a flash EIX (or whatever they are) when I got back but I can't notice the difference, starts first time, everytime, goes the same? Just pulled it out seems to be running ok, bit black but nows not the right time to look even at a used plug.

Secondly My 03 came with the NOZE in it but I leaned it to the NOZF needle. So I have a NOZE spare if you want to try it Cham.

Also came with a a R1475J looks like a variation of the above but I've done a couple a ggogles on it and can't find anything about how it relates to the NOZ coding on the Ktm needles. Looks much leaner all the way through.
I know that
• 1st digit of MARK on OEM’s tells you the KEIHIN Part Number
• NEXT TWO DIGITS (2nd & 3rd) tell you TAPER angle.
• NEXT TWO DIGITS (4th & 5th) tell you DIAMETER of needle.
• LAST DIGIT (6th) tells you L1. ( leaness) J is about middle, simlar to E ( I think)

Anyone familiar with an R1475J or got a chart that converts NOZ needles to the Kiehin default numbering or Vice Versa? Danger???

Showing my Ignorance here LOL!!