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Discussion in 'Dakar champion (950/990)' started by Gixxer2go, May 16, 2005.
Harsh maybe but premature...... definitely not
This is my round town mileage. I would expect a big increase on the open road.
At 160kph (100mph for the ho's at home)?
Having just finished reading this entire post I want to ask why?
1. Why hasn't anyone gone to a Mikuni book and looked up a needle that would give the optimal settings being sought? Since the exact size of needle shaft has been published here, it would seem possible to find one that was slightly richer off the midrange that seems to be the part that is so hard to bring into spec.
2. Or why hasn't anyone just taken a stock needle and put it in a Makita and sanded it down in the right places?
I had a new Honda 250 when they first came out and put a regular 2-smoke Mikuni carb on it. The jetting was off so I took my Makita out to the riding area and spent an afternoon pulling and sanding the needle until I got rid of my flat spots. Of course I just guessed where to sand, but the results were good. This is a lot of work on a twin, but it looks like some here have done an immense amount of work searching for the right fuel mixture anyway.
Are there any pics of the Sommer air box change?
Actually the stock needle in the correct position (stock) is perfect in every way and cannot be improved. It's the jet in front, and the one behind that upset the needle behaviour. The one in front is to lean (emissions I suppose)
and the Mains follow the normal behaviour of being to rich ("no matter what this bloke does... ie exhaust, air filter, he cannot damage the engine.) In another life I was a Mechanic..... and still do some casual work for a performance shop..... when they leave the shop they are running slightly rich.
Ive just started to tune my GasGas 300.... first thing I noticed was the rich main. I will use the wet pipe technique..... http://http://ktmtalk.com/index.php?showtopic=41083//ktmtalk.com/index.php?showtopic=41083
It's interesting that you assume after reading the posts that the problem is with the needle.... so much time is lost and the answers are never found.
The pilot is simple to fix and will give the smooth throttle response that is needed to control this high powered beast on the dirt. Also a rock solid idle.
The mains must be approached with caution. They must be brought down a little at a time..... when the needle starts to feel out of tune, go up a step(richer). It's a big job to make any changes to this bikes jetting.... but to get the results you must put in the time.
There was a lot of time wasted with venting inside the airbox, and with FP recommendations..... although they did give us the #45 pilot . Now is the time to finnish the job.
Redflash has the correct approach, and if the quality of his past work is anything to go by, then he will solve the riddle. I suspect that the pilot, pilot screw, and needle will be common to all.... but that the different bike modifications.... ie air filter, pipe.... will determine the correct main jets. I look forward to reading his future posts, and the posts of a few others on finding the correct mains with what modifications.
Autostream..... Perfect jetting across the range is what we seek ( it appears that the clue you gave me to solve this jetting riddle was a mistake This is to funny to talk about....).
Some of lifes biggest discovereies were F**k ups....
I think the 45 was KTM's first fix, and the air jet is the updated fix...but not sure, so don't quote me..
I'm realy no expert on this subject..
And i gues with me a lot of others are not. Maybe one of the experts here can make a summary of suggested settings for most common bike set ups.
Mine is a '04 with open pipes, SAS and EPC removed and sommer airbox cover installed. Want to remove the airbox mod next time i'm there.
Currently only the needle is one ring up.
Bike stalls at idle, sometimes. And worse, has less torque that when i mount standard pipes back! Clearly something not optimal.
After reading this topic i guess starting by removing the sommer cover, installing 45 pilots and setting the needles back to stock.
Thats what i make of it.
After doing the suggested optimum i want to make a dyno run to see if the A/F reading is OK.
Possibly some of you experts can give me a good carb setting to start with before the dyno. I'l promise to post the final settings and my dyno run when i'm done Thanks in advance!
#45 @ .25 turn out (Factory Pro) Pilot jet.
Needle position 2nd clip (stock)
This should solve most problems
For best HP you may need to drop main jet size. Stock is 155 front 160 rear.
I run 142.5 and 145
I would suggest trying 147.5 front and 150 rear for your first Dyno run while monitoring your A/FR. These should not be allowed to drop below 14:1 @ WOT.
If you ride before testing you cannot hurt it if you don't thrash it.
If there is a problem with to lean a main jet..... It won't feel right during normal acceleration. It will feel that the needle needs to be raised (richened). If it feels like this do not wring it's neck (go flat out)
I wouldn't worry to much about the summer door..... It may help. Some like myself do not want to lower the air intake any more, ie water crossings.
A dyno test with AFRs will contribute enormously to this thread.... WELCOME
I fear lean bike's so i'l probably try a 150/155 front/rear then
Why does the pilot yet have to be a FP? think their hard to find here in holland, doesnt KTM original have a 45?
And by .25 you mean the idle mix screw just .25 turn out i suppose.
sommers door is going off for a desert trip in Africa, dont want any more dust then neccesary.
The pilot does'nt have to be a Factory/ if you are searching you kan buy them also by mikuni/ or antoher manufactor.
be awere when changing main pilots the weather and conditions here in holland are diffrent , compared to the foreign/US models and so they have also other main jets due to emission rulles.
Basicaly the bikes are the samen, carb settings from factory are the same to. So i'l gues american settings would work as well here, as long as the altitude is about the same.
What freaks me out is that the thing has 6 jet's, seams so easy to mess it up.
Yes 1/4 turn. My Idle is a solid 1250rpm. I open my front a screwdriver blade thickness more than the back. Yes opposite of the main jets
Carbs are the same around the world. some Yanks got 158, 162 mains
I am in Australia
Factory Pro are the only people to make the "78" series jets in 38, 40, 45 ect. You should be able to get them at Sommer....
Tonight I filled the tanks. Light came on at 265km..... 19.45 Lt @ 292km... very good That's more like what you would expect from a 1000cc bike around town.
Should be good for 345km per tank. With my extra tanks fitted....X 10 Lt... 500km round town.... very very good
For the right numbers/jets look at the partsmanual at LC8info
there could be a diffrence,because the emission rulles here are diffrent then over there! so ther could be also diffrent jetsizes....
16 pages and no definate "just right" settings !?There seems to be 2 "main" schools of thought on this old subject.
1) Use stock mains, raise needle one notch and maybe a 45 pilot jet....or
2) Use factory pro needles with larger jets (165,168,170 ?) raise needle to 4th spot and use a smaller pilot maybe #40
Is the "problem" we're trying to solve the low power or flat spot at lower RPMs ? I found that I was riding my 950 like a top end type bike on the twisty roads because I had little low end torqe or horses.For me #2 is by far the best all around on and off road.Sommer air box mod,165-168 mains 4th position on needle and #40 pilot. Is there another general consensus that I don't know about ?
Anyway, I hope this helps someone !
Killer Whale KTM
This, KW, is a good question. Quite relevant.
So, you're looking for more oomph down low, say, below 4500 rpm?
I'm not sure that's a big concern to me; I'm accustomed to revving bikes -- that's how I rode my old beemers, and even the KLR. I mean, I guess I don't really expect much down low. My 950 seems to pull fine in the low three gears, although I do get some pinging in third if try too hard from around 3000. Of course, I'm using regular unleaded. The bike idles perfectly at 1400 rpm once warm. A little choke when the motors cold, and it starts up with alacrity regardless of air temp. I have no real complaints about this bike; it's head and shoulders above anything I've had.
All that said, the bike does feel a tad lean pretty much all over. I'd like it to feel "right". How's that for an objective?
I suppose I should add that I'm not gonna cut up my airbox, and I'm keeping the stock exhaust for the foreseeable future. I have no incentive whatsoever to "find more on top".
I find the 950 quite responsive, driveable, but there are a few spots where response to the throttle could be smoother, more predictable. Seems the more I ride, the less I notice these -- perhaps I'm adapting, driving around those spots.
So, what I'd like is smoother throttle response, less pinging coming off low rpm under load, and reduced lean surge at cruising speed. I'm not sure I've seen a proposal for stock airbox and exhaust that simply fattens the mix a tad everywhere above idle. Have I missed something?
If you just want to tidy up the bottom ends lean spot with standard airbox and with or without muffler changes/mods, all you need to do is go to the 45 pilot (K2m's fix) OR the 70 air jet 60031037070 (KTM fix)
I have the 70 air jets and it made a huge difference to rideability down low, particularly when in traffic (needed idle micture backed off to 1.25 turns).
K2M went with 45's and it did similar.
Since then I have gone up and down in the needle, best at standard slot for me...
also down and up in the mains. Leaner was worse, but up one step richer has REALLY smoothed it out...can't tell about max power yet as I could not get traction in 1, 2 or 3rd with Karoo on rear...that may be a good sign..
Personal & proffessional experience tells me, unless you want to start jetting from the very start, have a dyno, time and money...Don't F**k with the standard airbox. This changes many of the characteristics of the way the engine breathes... as does changing vent lines etc.
Opening up the airbox DOES affect many things in the jetting & way engine breathes...but even if you sort the jetting out, all it will do is give a little more top end as it breathes easier (as long as mufflers changed as well)
Unless you have time, money, patience and want to really add some top end, I personally would not recomend changing what KTM spent many development dollars doing.
Even slight variations in the mods to the airbox, whether it be snorkel or Somner mod, will give a different result and need different jets, as will differences in where you put the vent hoses....many of these pages of posts have subtle variations from each other, so it is unlikely most of it will apply specifically to your bike unless you have done exactly the same things.
Fix up the lean spot at the bottom end (my guess is this is purely a result of making it pass emmissions standards) with the above jet change and I bet 99% of you will be happy. Note that emmission standards only apply to typical 'road cycle' tests, generally under 100 kph and do not affect the top end or full throttle. (Noise regs do though hence the EPC).
Just my personal experience....
Autostream aren't you at 0'? I am at 4,500'/1,500m. Curious how lean/rich I am. Local KTM dealer (good guys) says #45 pilot, needle up 1 and backed off 1 turn, with new cans. Thinking about that and 2-3 3/4" holes in the back of the snorkle (rider's side/prefilter) for a little more air but I really don't want to mess with the jetting too much. It is running smoothly throughout the powerband especially with the Akros and SAS gone and I don't want to f-up a good thing. Someone tell me about elevation, pulease.
No I will have to disagree.... My current work has the jetting just right
Orange Roughy At 4500ft you will be running rich. The correction factor would be 0.935 to 0.94 at this altitude... ie multiply the jet number by this figure...
Autostream ....Maaaate ...you are not giving enough information..... which combinations of main jets and needle position did you try? And have a great time next week, I wish I was going as I haven't learnt to fall off yet. To much time spent working on this bloody jetting.
Did a bit of mixed city and open road..... Low fuel light came on at 282km Very good
Currently I'm running the FP recommendations of 175/180 mains, 45 pilot, and since the dealer installed the kit, I would guess the needle & air screw settings are the same as the spec sheet from FP. Elevation is about 400 ft. above sea level. I have the Wings (Akro copies) with the smaller baffle, and haven't made any changes to the airbox or cannisters. I have yet to dig into the carbs myself to adjust the settings, but that's coming up.
I noticed that it requires little to no choke to start the bike up when it's anywhere above 45 degrees, and only about 1/4 to 1/2 choke when it's in the teens. You can smell the fuel though when it's idling; too rich for sure. Also, the bike doesn't seem as crisp in the mid-range; looks like a needle adjustment is in order. I don't spend much time in the upper rev range, but use it to get going in a hurry, then settle mostly into commuter mode. Once above 5500 to 6000 rpm, the bike picks up speed in a hurry. I'm probably a little rich up top too, so I'm thinking of backing down on the mains too.
The amount of information in this thread is both overwhelming as well as immensely helpful. I'm going to do some review work here and try some of the recommendations given. Thanks to all for contributing to this thread!
If you hold it open at the top of 4th or 5th gear and it sputters at 8+k rpm then you know its way too rich. mine was with the 175/180