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KDX 220 low end sputter
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Posted by: NCFRC---------------------

I have a 35mm carb on my 220 and overall it runs pretty decent but I've been chasing a low end , 0 to 1/4 throttle sputter.

Any suggestions ? I 've changed the pilot jet and needle all over the place.

I'm thinking it's too rich ,, but honestly hard to tell.

Posted by: julien_d---------------------

What sort of sputter are we talking about here? All 2t's will sputter when cruising at low throttle openings. They don't cruise the way a 4t will.

If it stumbles more than it should, it could be rich. Doing a plug reading with a fresh plug after riding it solely in the "sputter zone" should tell you if it's lean/rich.

Posted by: NCFRC---------------------

I'll try it with a fresh plug.

I'm only comparing it to my son's 200 which has almost no
sputter at low end.

It doesn't run bad or lack on power , just sounds like it's missing.

Posted by: julien_d---------------------

Quote:

Any suggestions ? I 've changed the pilot jet and needle all over the place.

What changes have you made? Any difference at all between the changes?

Posted by: carlby114---------------------

Quote:

Originally Posted by NCFRC

I have a 35mm carb on my 220 and overall it runs pretty decent but I've been chasing a low end , 0 to 1/4 throttle sputter.

Any suggestions ? I 've changed the pilot jet and needle all over the place.

I'm thinking it's too rich ,, but honestly hard to tell.

Im having the same problem with the stock 33 mm carb and I cant get rid of it either . I was going to try a 35 mm carb off a 200 . I cant seem to get any answers either .

Posted by: carlby114---------------------

Im having the same problem with the 33 mm carb . I wanted to try a 35 mm off a 200 . I was hoping that would solve the problem . I cant seem to get any answers.

Posted by: NCFRC---------------------

Well I believe I've found the running difference between our 200 and 220 .

My son's 200 has 10.5 compression and my 220 has 8.3 compression
I was running the same fuel and Fuel / oil mixture in both bikes.

The 200 with more compression can burn the mixture just fine but
the 220 with lower compression can't at lower rpms.

What I did last night was to mix a new batch of fuel with a higher oil ratio 40:1 " I was running 28:1 " and the bike runs much better.

Sputter's not 100% gone but a great improvement.

I moved the jetting and air screw all around with no change like it
made by changing my fuel.

This winter I'll put in a new Wiseco and the head machined to get the compression where it should be.

I should have known as I ran across a similar situation years ago , many years ago and had forgotten about this.

Let me know what you find with your bike . The 35 mm is worth the performance gain but don't change it to get rid of the sputter.

Posted by: jonooffler---------------------

Hi this sound just like my bike (2003 KDX 220 stock- I think ), I bought it about 5 weeks ago, at the time I could not ride but the bike started and reved fine all sounded good.
I have just taken it out for the first ride and i feels alful, from cold the engine felt like it was about to die if you opened the throttle it would die It felt like it was running on full choke.As the bike warmed up it got better with the high revs pulling well but low down it is very lumpy and bogged down. The plug is and 8 the gap is fine and its dry but a dark ish brown.
I have not tried pulling the carb out to clean it but I'm thinking that maybe the pilot jet may be blocked. The last owner didn't own the bike long and did not know if the last owner a changed the pipe and jets.
So any help that you can give would be great.
Jono

Posted by: GreatBritishRob---------------------

Quote:

Originally Posted by jonooffler

Hi this sound just like my bike (2003 KDX 220 stock- I think ), I bought it about 5 weeks ago, at the time I could not ride but the bike started and reved fine all sounded good.
I have just taken it out for the first ride and i feels alful, from cold the engine felt like it was about to die if you opened the throttle it would die It felt like it was running on full choke.As the bike warmed up it got better with the high revs pulling well but low down it is very lumpy and bogged down. The plug is and 8 the gap is fine and its dry but a dark ish brown.
I have not tried pulling the carb out to clean it but I'm thinking that maybe the pilot jet may be blocked. The last owner didn't own the bike long and did not know if the last owner a changed the pipe and jets.
So any help that you can give would be great.
Jono

Try reading your other post.

Posted by: NCFRC---------------------

The other thing That I believe may contributing to this is Ethanol in gasoline " pump fuel " . Not a good thing when you fill your 5 gallon
can that there's 1/2 gallon of Alcohol in the mix.

I just learned that the marina's have non-ethanol fuel because of so many running problems ,, the only slight negative there is it's only available in 87 octane.

Posted by: jth---------------------

NCFRC
I had the same problem after I went to a full RB modded engine.
¼ throttle bog (like a lean bog) + pilot and air screw adg. made no change.
Problem solved by going to the next larger main jet.
When you changed to the 40:1 fuel you effectively richened it up pretty good
With your results suggesting that you are experiencing a lean bog.
Try a bigger main jet with the 40:1 fuel and let us know how it works.

Posted by: NCFRC---------------------

I don't believe it's a lean bog , I'm quite sure it's a rich stutter like the fuel isn't burning completely.

Posted by: jonooffler---------------------

I have just changed the pilot jet over the other night but have yet to ride it ,it was running a 42, my local bike shop had a 38 so I have dropped that in I hope to ride it over the next few days to see how it goes. I did just kick it over and it does feel much better.

Posted by: jonooffler---------------------

Well i tried the new 38 pilot today it feels a bit better, it still pulls well at high revs in the higher gears but low gears still has the stutter.
I rode for about 9 miles then pulled over to adjust the air screw.The idle was fast and the breathers were all leaking fuel. I killed the engine and restarted it fine, then I tried to adjust the air screw, when it is in the motor dies as you open it out it picks up but does not change if you go out more.HELP
Any ides before I trade it in for a 4 stroke.
Jono

Posted by: NCFRC---------------------

38 is way too lean for a low speed pilot jet.

Is this a 33 or 35 mm carb ?

Send your carb and cylinder head to Ron Black

Posted by: jonooffler---------------------

Hi it's a 33 carb, I would love to get the RB work done on the head but that might have to wait until the wife starts talking to me after I brought the KDX home

.I have decided to change back to a 42 and then flush the tank out a start with a new mix of fuel i mixed the last lot 32-1 so I going for a higher octain and a 40-1 mix to see how that runs.
I have only just started riding the KDX off road but must say after 2x DR125 1xDT125R 1xDRZ400 1x XR250R and a TE610E this one is the best. I ride slowish green lanes and if I can get her running right at low revs this is going to be a great bike.

Posted by: NCFRC---------------------

It's a lack of complete burn of fuel at low rpm's.

Were you running 87 with this problem ?

You'll also see it with premium oils and a high flashpoint , more so if it's mixed too rich ,,,, 40:1 should make a noticeable difference.

Posted by: james.keaton---------------------

I have always ran 93 octane and bel-ray 2 stroke oil in mine, as did my nrother in law who had the bike 15 years before selling it to me.

Posted by: jonooffler---------------------

Hi I was running 95 with a 32-1 I flushed out the old petrol and change the jets back them ran out of time so this weekend will show if its worked.
Thanks again for all your input

Posted by: carlby114---------------------

[QUOTE=carlby114]Im having the same problem with the stock 33 mm carb and I cant get rid of it either . I was going to try a 35 mm carb off a 200 . I cant seem to get any answers either .[ change the needle . just put in a a CEK cleaned it up just off idle . the stock needle is a B the C is actually a smaller dia. but the taper comes in later, getting rid of the sputtering , 38 pilot 145 m 2nd groove 1 3/4 a s go on line to pats small engine plus (there only $5.50)

Posted by: jonooffler---------------------

Hi mate sound like we have have the same issue, every one keeps telling in on forum that the 38 is too small, I have yet to look at the main and clip on mine but if yours is set as you say thats the stock setting.
Have you changed the clip on yours ? the local bike shop told me to drop it down a notch to run it lean to see what that would do. I have sort of run out of time with mine at the moment so it will be a few days before I can check mine out to se what it is set to.I have been give a few other things to look at but have not tried them yet, they are ;
The KIP valve.
Reeds
I don't know if you have tried any of these out .Please keep me posted I would love to know how you get on.
Jono

Posted by: NCFRC---------------------

Well I have to admitt when I'm wrong as we rode this last weekend and it stuttered as bad as ever. I even went from a 42 pilot up to a 45 and the stutter is the same. The 45 did seem to help low end torque above the stutter.
I'm really leaning towards pulling back out the reed cage and double checking the 607 reeds I installed . They were nice and flat when put in this spring but you never know. Another rider commented about trying the V-force 3 cage but thats an expensive try.

We're running Maxima 927 at 40:1 and they still smoke alot.
I may try a higher mixing ratio for the smoking but I don't think it will help with the stutter.

Again this seems to be a 220 characteristic as my son's 200 runs perfectly smooth at any rpm setting.

This 220 has far more pull / torque but maybe the screwed up porting causes this problem ?

Somebody must have found the cure

Posted by: jonooffler---------------------

Hi I rode into work today on the 38 jet I did feels bit better with the stutter ( but not much ) The down side was a lack of pick up, I played around with the air screw with out much change. The guy I bought the bike from said that he ran 50-1, some people say is to low an oil mix. The lower you go the more rich it will run so I'm not sure that it will help.
Having looked on a few forums I found one thread about the air box lid and snorkel, on guy claimed that he could never get his 220 to run well until he removed the snorkel but leaving the lid in place, after that it was fine.
I have just removed the item and will go out later and try it out, if it works I might go back to the 42 pilot and see how that feels.
Good luck Jono

Posted by: jonooffler---------------------

Ok tried that and it felt worse, very unhappy at low revs and not great at high revs. Ran round to my local MX bike shop and let the owner have a ride on it and he came back saying that it felt rich and lean at he same time ! He suggested going lifting the needle one notch and see what that does So he thinks make it run richer.
Will give that a go over the next few days and will post the findings.
Jono

Posted by: NCFRC---------------------

So you have the snorkel on or off the bike ?
I'm running 40:1 mix ratio now but am going to try 50:1 this coming weekend as for average trail riding they smoke really bad and alot of spooge.

I even talked to Jeff Frederette and he's always run 50:1 but also commented that this low end sputter is fairly common no matter how you jet the bike.

The other comment that makes sense to me is that the sputter gets a little worse the longer you ride at a slower pace. Which is a sign of too much oil thats building up and then after you clean it out it runs better. But I've never fouled a plug .

I won't get into oils but I believe if you buy a very high quality oil
that you can't mix it at too low a ratio. Again Kawasaki says 32:1 only to cover any oil thats available and to have plenty of it.

This will be a long term project for me as I'm going to have the head and cylinder done this coming off season to improve the performance to the next level .

I hope this rambling helps to some degree.

As of today I have a 35mm carb ,45 slow jet , 152 main , needle 3rd clip , pilot air screw 2 out .

I'm confident that 50:1 will clear it up some. Fine for trail riding.

If your racing and run the bike from 1/2 to wide open "all " the time then I'd stick with 40:1 .

Posted by: jonooffler---------------------

Hi thanks for the info I spoke to the guys at the local MX shop and they rode it it and came back saying that it was running rich and lean at the same time, when the the slide comes off the stop it runs rich to start with but then starts to lean untill it opens over the 1/4 to 1/2 mark, they suggested that I should lift the needle to the 3 clip and try that.So I now running 40-1 38 pilot 3rd clip and no snorkel I have yet to ride this setting but I will let you know how it goes.
As for the oil mix as I said the last owner claimed that he used 50-1 when he had it but I'm starting to think that he never took it out ( maybe he could not get it to run right) the problem I have is I do around 50% slow trails and 50% fastish road work so I'm not sure what to go with.
the silkoline oil I have says that it will work at 50-1 so I might drain the tank and re mix ( again

).
It's a real pain every one says how good this bike is at woods work but at the moment it's unrideable in low speed/rev work which is the sort of riding I do I would be nice to ride one which is sorted just to see if it\s the sort of bike that I'm looking for. I'm starting to think maybe a 4 stroke would be better for me.
Jono

Posted by: NCFRC---------------------

I couldn't wait untill the weekend so I mixed up a fresh batch of 50:1 fuel.

First impression of a quick few mile ride is that it smartened it up quite a bit , not perfect but alot better than 40:1 .

Posted by: sr5bidder---------------------

so Jono why have you not changed the main jet?, checked compression?, pulled the head to see if there is the stock piston in there with a crack (220's are known for doing this)????

also I don't know why there are 2 threads running on the same subject....

but anyhow as julien_d would tell you make shure the kips is not stuck open as this will cause your kdx to run like crap on the low rpms. with the kips open below 6000rpm the engine will have a lower compression ratio than it should

Please step away from the carb!

Posted by: jonooffler---------------------

Hi there the problem is low speed running so the main jet should be fine it runs fine and pulls well in the high rev range.I have has two off road bike shops ( both MX based ) and they have both said the rings and piston are fine as the bike pulls so well, one of the shops ( a Kawa dealer ) said that the KIP valve is fine, so it has to be a carb/ jet issue or it's just one of those 220 problems.
As for the 2 threads one is from me the other is from another 220 rider with the same problem having spoken to other 220 owner they have taken a long time to get them running well.
I'm sorry that we both posted treads but I thought that was the idea of a forum.

Posted by: NCFRC---------------------

The Maxima Oil I'm running has this posted on their technical information website . Most 2 strokes are over lubricated at idle , sufficiently lubed at half throttle and poorly lubricated at full throttle .

oil / gas ratios for various riding ,

Recreational 50-60:1
Moto X / Enduro / X-Country 32-40:1

Posted by: jonooffler---------------------

Hi just tried out the new setting and it feels much better there is still a bit of a stutter but its better than it was 40-1 38 pilot clip 3rd and no snorkel.I think the oil mix might need to be changed I parked up to adjust the air screw and when I rode off after it had idled for a bit it had the stutter again,I'm going to ask around at silkoline and see what they say.
Thanks again all and sorry if I have been a pain over this.
Jono

Posted by: whenfoxforks-ruled---------------------

Another circle jerk jetting issue erroneously made worse by messing with the oil ratio, duhhh? You was on the correct path down sizing the pilot. Start with replacing the float valve and checking the float height.

Posted by: jonooffler---------------------

I must admit i don't like messing around with the oil mix to make the bike run, the label on the bike calls for 32-1 if the maker thinks that what it needs that what it should run with.
The float has been checked and is right, one of the dealers suggested going to a 36 pilot but that is way off what most 220 are running on, I might try to get one just to see how it feels.
Thanks for the input, I hope that I can sort this out soon I'm missing good riding at the moment.
Jono

Posted by: whenfoxforks-ruled---------------------

Listen to the bike, not anyone elses, they are all different, just like people. Try the 36, see where the air screw adjusts to its highest rpm, with in 1/2 turn of the stock setting, good. If you still are scratching you're head, and blowing spooge, change the float valve. It seems you can grasp the lunacy of chasing a rich jetting issue by reducing the oil ratio, and there by putting even more fuel in. Have you read the plug for timing and correct heat range? This sites technical archives are number 1, and no one is hardly ever in there, its easier to assume they are the first with spooge?

Posted by: NCFRC---------------------

When you throw out an question or comment you have to be open to receive all responses , if there based off knowledge / experience or just bull ****.

Good luck , you'll get it figured out.

Posted by: jonooffler---------------------

Thanks for the support mate It's good to know that I have you guys out there.
I going to aviod messing around with the oil mix I want to stay at 40-1 I'm going to check the float level a few people have said about this I just need to know how to check it for my self as so call pro's have said it right but I don't know how they checked it.Jono

Posted by: whenfoxforks-ruled---------------------

Long as you understand, reducing to 40:1 is making your entire throttle range richer. You will have to lean all the circuits. There is but 1 source of solid information, SAE documentation. Anything else is marketing and guy talk. There are builders, engineers, Doctors and scientists that have frequented this forum for over 10 years. Their input is in the technical archives, and the SAE websites. Awakening from years of blindly playing with dirt bikes, as does plenty of people, was not that big a deal for me. Others, good luck. I do enjoy finding out I am wrong, that means I learned something today, and it was not a waste. If the oem set the bike up for 32:1, it is not to screw you, all the parts in the carb, and the jetting baseline is wrapped around 32:1. Keep it simple. Here is where Okie lives(The Boss), read and enjoy, http://www.dirtrider.net/forums3/fo...sc&daysprune=-1

Posted by: sr5bidder---------------------

I have a rm125 that ran fine on the top end of the rpm range and had nothing down low..I DID a compression check and it was 90psi...tore it down and found a badly worn piston...
what you have posted is the experts said this and that was fine, but you did not say the experts said the compression was at xxx or the experts tore down and inspected the kips

I try to stay away from shops and do my own repairs, its sloww going at times but I have rebuilt 5 bikes in the last 2 years and chased carbs, tweaking and adjusting for hours on end and alot of times it was something else.

these bikes perform reasonable well at factory settings and properly jetting them makes them perform extreemly well so all I'm saying is if the carb clean, jetting is close and settings are correct, I would take a look at other areas reeds, kips system, cleaning and repacking the exhuast (yuk)

Have you tryed changing the heat range on the plug yet?

Posted by: NCFRC---------------------

Quote:

Originally Posted by jonooffler

Thanks for the support mate It's good to know that I have you guys out there.
I going to aviod messing around with the oil mix I want to stay at 40-1 I'm going to check the float level a few people have said about this I just need to know how to check it for my self as so call pro's have said it right but I don't know how they checked it.Jono

Keeping your base line consistent is probably the most important thing . The other would be to keep good notes on what a particular change did to the bike and only make one change at a time . I've fallen victum to multiple changes , lets try that , and even if it did help you'll never know what actually fixed it.
Sometimes unless you find the right person , a dealer only knows the text book answer and doesn't have any real world experience.

Posted by: jonooffler---------------------

Well the last setting works with a bit of a stutter but it's much better than it was it's now 38 pilot 40-1 mix and 3 rd clip I have just placed an order for a 35 pilot which I'm going to try just in case but I do feel that It's going the right way now.
Just before any one says the 35 is way to small the UK spec bike should have had a 38 fitted as standard.
Jono

Posted by: sr5bidder---------------------

Jono is this an oil injected model 200sr?

I hate that the site no longer contains the "bikes" under the users name!! it leaves so much in the air when trying to help

Posted by: NCFRC---------------------

That's another arguement for not comparing bikes , none are the same !
I've got a totally different combination , the bike fires up on the first kick almost
every time , runs 95% perfect and I'm very particular. A nice med/dark plug with very good low end torque.

05 / 220R
06 / 200H
Maxima Lubes
Lucas products
Prolong ETP

Posted by: sr5bidder---------------------

must be the "my son's monster kdx" that "runs 95% perfect and I'm very particular A nice med/dark plug with very good low end torque"

look familiar?
I couldn't wait untill the weekend so I mixed up a fresh batch of 50:1 fuel.

First impression of a quick few mile ride is that it smartened it up quite a bit , not perfect but alot better than 40:1 .

from your low end sputter thread

as you said if there based off knowledge / experience or just bull ****.

alot of bull **** can be sorted by memory of what had been said previously

Posted by: NCFRC---------------------

This thread is for more positive suggestions and if you'd paid attention we're talking about a 220 here not a 200 .

Thanks for your input anyway

Posted by: liven07---------------------

If you were having problems with your kips your top end power would be lacking and your bike should run just fine with stock fuel/oil mix and jetting. If you are sure your carb is clean and the right jets, you should test the compression. If that is all good there is a very good chance it could be your reed valves, I would be willing to bet the bike is basically running off the power valve(high end), with the reed valve(low end) barely working . If there are mods on the the bike you might want to check those out and make sure there used correctly.

Posted by: Kaw4me---------------------

According to Jeff Frederete this a very normal running characteristic of a stock porting 220 . Not that aftermarket porting would guarantee a fix.

I'm sure this was posted earlier in the thread but it's good to finalize things on a more positive note.

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KDX 220 low end sputter

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