blind luck is not a good jetting guide
- jlove1974
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blind luck is not a good jetting guide
I guess this qualifies as my first post. And it's a jetting question
I have a 99 KDX220 that was jetted stock 42p 145main and no airbox lid
In the summertime. My pre-mix is Amsoil dominator 40:1
It ran great but the typical 220 signoff at high-mid rpm.
It has had a wiseco piston installed in the topend.
I purchased a parts bike which is a 95 KDX200, which came with a Pro Circuit 'works' pipe and what I thought was the stock carb (35mm).
I put the pipe on but kept the stock silencer and then opened up the 'stock' 35mm carb. Found out that it has been bored out to 36.5mm and rejetted.
Pilot is 50 and main is 165! The carb has no divider plate etc...
So thinking it was gonna be pig-rich and relatively safe, I put it on my bike along with the 1174 needle that came with the 200s (and on this bike).
I immediately got a wider stronger powerband, with a slight bog at about 1/4 throttle (it's 90+ degrees here with 80% humidity). I can tell it's rich at idle @ 2.5 turns out plus w/ lots of smoke throughout the whole throttle
So I replaced the pilot w/ the 42p from my old carb and bought a 155 main jet. I know these are big jumps down but from what I am reading here, this is the jetting many of you guys use on the 220.
However I swapped the 1174 needle w/ my old 1173 needle since it's a tad richer. Figure this would keep me safer with the smaller main jet.
Now the bike will not rev out past 1/2 throttle. It acts like it's way too rich on mid/top sputtering etc.
So to recap:
700ft elevation
90 degrees avg w/ 70-80% humidity
KDX 220
stock reeds
PC works pipe
stock silencer
no airbox lid
50 pilot
165 main
1174 needle 3rd clip
runs good, slight bog from 1/4 throttle
switched to
42 pilot
155 main
1173 needle 3rd clip
idles perfect runs like crap from mid-throttle on. Does the 1 size richer
needle make THAT much diff? Why are the 220s richer than the 200?
I am probably going to do an RB carb later on down the road. But I would like to play around with this carb in the meantime.
Let me know what you guys think.
TIA
I have a 99 KDX220 that was jetted stock 42p 145main and no airbox lid
In the summertime. My pre-mix is Amsoil dominator 40:1
It ran great but the typical 220 signoff at high-mid rpm.
It has had a wiseco piston installed in the topend.
I purchased a parts bike which is a 95 KDX200, which came with a Pro Circuit 'works' pipe and what I thought was the stock carb (35mm).
I put the pipe on but kept the stock silencer and then opened up the 'stock' 35mm carb. Found out that it has been bored out to 36.5mm and rejetted.
Pilot is 50 and main is 165! The carb has no divider plate etc...
So thinking it was gonna be pig-rich and relatively safe, I put it on my bike along with the 1174 needle that came with the 200s (and on this bike).
I immediately got a wider stronger powerband, with a slight bog at about 1/4 throttle (it's 90+ degrees here with 80% humidity). I can tell it's rich at idle @ 2.5 turns out plus w/ lots of smoke throughout the whole throttle
So I replaced the pilot w/ the 42p from my old carb and bought a 155 main jet. I know these are big jumps down but from what I am reading here, this is the jetting many of you guys use on the 220.
However I swapped the 1174 needle w/ my old 1173 needle since it's a tad richer. Figure this would keep me safer with the smaller main jet.
Now the bike will not rev out past 1/2 throttle. It acts like it's way too rich on mid/top sputtering etc.
So to recap:
700ft elevation
90 degrees avg w/ 70-80% humidity
KDX 220
stock reeds
PC works pipe
stock silencer
no airbox lid
50 pilot
165 main
1174 needle 3rd clip
runs good, slight bog from 1/4 throttle
switched to
42 pilot
155 main
1173 needle 3rd clip
idles perfect runs like crap from mid-throttle on. Does the 1 size richer
needle make THAT much diff? Why are the 220s richer than the 200?
I am probably going to do an RB carb later on down the road. But I would like to play around with this carb in the meantime.
Let me know what you guys think.
TIA
- Indawoods
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- Location: Midwest
I'd take that carb off and send your stock 220 carb to RB. Hard telling what is going on with that 35mm carb or what work was done or even where it came from originally. It was probably a eBay buy that turned out to be unworkable.
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
- jlove1974
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That's the plan to send my stock carb off. Once I get the extra $$$ for that.
However looking at the modded carb I can tell that it's been bored probably with a brake hone after the needle jet tower was removed. it's consistant all the way thru w/ hone marks. I used a micrometer to measure it at 36.5mm.
Then comparing it to my 33 someone has hand-ported the intake bell side.
It looks like pretty good work to me. I have ported intake manifolds by hand. What exactly makes a carb unworkable unless it's damaged/worn?
It's a center-bore job so that's probably why it has the slight stumble off-idle. Probably cannot get rid of that with just changing jets.
The slide is still stock #5 and it still had the stock needle R1174K with the 1 size richer pilot (50) and the two size richer main (165).
Does anyone know where to get a #7 slide besides spending $65 on one?
I'd like to try that with a xEL or xEK needle to see if it would run better.
But if I have to buy two needles and a slide I might as well do the RB carb.
Sure it's not an ideal carb but based on the way it came off the other bike
it ran pretty darn good when combined with the PC pipe. Good enough to ride on while my other carb is being sent off/finances saved up....etc.
However looking at the modded carb I can tell that it's been bored probably with a brake hone after the needle jet tower was removed. it's consistant all the way thru w/ hone marks. I used a micrometer to measure it at 36.5mm.
Then comparing it to my 33 someone has hand-ported the intake bell side.
It looks like pretty good work to me. I have ported intake manifolds by hand. What exactly makes a carb unworkable unless it's damaged/worn?
It's a center-bore job so that's probably why it has the slight stumble off-idle. Probably cannot get rid of that with just changing jets.
The slide is still stock #5 and it still had the stock needle R1174K with the 1 size richer pilot (50) and the two size richer main (165).
Does anyone know where to get a #7 slide besides spending $65 on one?
I'd like to try that with a xEL or xEK needle to see if it would run better.
But if I have to buy two needles and a slide I might as well do the RB carb.
Sure it's not an ideal carb but based on the way it came off the other bike
it ran pretty darn good when combined with the PC pipe. Good enough to ride on while my other carb is being sent off/finances saved up....etc.
- Indawoods
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Ron cuts the slide to a #7.... he also modifies the Jet Tower so it is a tremendous value. That is probably why you cannot get it jetted right running a #5 slide.
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
- jlove1974
- Supporting Member
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ya that's what I was thinking as well. Also the divider plate probably helps out as well with any bogging when you whack the throttle wfo. It's essentially a copy of the airstriker carb, right?
If I can find some other PWK slides I might mess around. Right now I am gonna go back to the way it was when it ran pretty good. It makes
sense that the leaner needle works better with the richer jets BUT
it makes no sense why the 1 step richer needle doesn't work with the leaner
jets. I think the Kawi needles just suck now lol
If I can find some other PWK slides I might mess around. Right now I am gonna go back to the way it was when it ran pretty good. It makes
sense that the leaner needle works better with the richer jets BUT
it makes no sense why the 1 step richer needle doesn't work with the leaner
jets. I think the Kawi needles just suck now lol
- Indawoods
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Pretty much...
Ron also modifies the Air Striker carbs so Ron's mods are not a copy of anything. They are his own R&D products.
Ron also modifies the Air Striker carbs so Ron's mods are not a copy of anything. They are his own R&D products.
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
- fuzzy
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Wacking the throttle WFO on a 2-cycle, and having it rip clean is jetting period. Rons magic comes into play at lower RPM low-mid throttle openings, and my magic I mean thottle reponse and some unfound torque you didn't have before.
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
- jlove1974
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OK back to my OP:
36.5mm mystery-reworked carb
no divider plate
stock 220 engine
PC pipe/stock silencer
700-2000ft above sea level
summertime temp of 90
what would be best guesses as to where to go from:
165 main
50 pilot
1174K needle
#5 slide
no airbox lid
runs good enough for trail riding but smokes like a diesel at times
I have tried:
155 main
42 pilot
1173 (stock 220) needle
no airbox lid
it idles well, not much smoke and and it was a little "pipey" off idle but then dies/sputters (NOT a lean boggg) when I whack the throttle open.
Guess once I get it revving out to where I can actually do a plug chop, then I'll know for sure. If it's as simple as a main jet change I am happy.
I have got one more MJ which is the stock 145 but I'm skeered of that one
36.5mm mystery-reworked carb
no divider plate
stock 220 engine
PC pipe/stock silencer
700-2000ft above sea level
summertime temp of 90
what would be best guesses as to where to go from:
165 main
50 pilot
1174K needle
#5 slide
no airbox lid
runs good enough for trail riding but smokes like a diesel at times
I have tried:
155 main
42 pilot
1173 (stock 220) needle
no airbox lid
it idles well, not much smoke and and it was a little "pipey" off idle but then dies/sputters (NOT a lean boggg) when I whack the throttle open.
Guess once I get it revving out to where I can actually do a plug chop, then I'll know for sure. If it's as simple as a main jet change I am happy.
I have got one more MJ which is the stock 145 but I'm skeered of that one
- jlove1974
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also, one more question:
Float level. Are the tangs on a STOCK pwk float bent in a downward curved bend?
Or should it be flat and then bent down/up at straight angles?
When I set my float height to 16mm, I got fuel out of the vents. When I set it to 20mm, it was OK but I still had some fuel coming out of the overflow while sitting and not running. I am thinking this is affecting my jetting too.
I am thinking it's the tang that is bent down and curved, and that isn't reflecting the true float height vs the amount it's pushing on the needle rod.
So my question on this is, should it be bent FLAT and then restart w/ the float height? the KDX service manual illustrations leave something to be desired.
I guess this is why I need a fuel level gauge lol....
Float level. Are the tangs on a STOCK pwk float bent in a downward curved bend?
Or should it be flat and then bent down/up at straight angles?
When I set my float height to 16mm, I got fuel out of the vents. When I set it to 20mm, it was OK but I still had some fuel coming out of the overflow while sitting and not running. I am thinking this is affecting my jetting too.
I am thinking it's the tang that is bent down and curved, and that isn't reflecting the true float height vs the amount it's pushing on the needle rod.
So my question on this is, should it be bent FLAT and then restart w/ the float height? the KDX service manual illustrations leave something to be desired.
I guess this is why I need a fuel level gauge lol....
- Julien D
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- jlove1974
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cool. I'll keep y'all posted as to what works then.
I think I'll go back, set my float level stock, use what worked before (50/165)
then play w/ the needle/AS until my bottom end cleans up.
Then lean it out for power and to get rid of smoke.
Maybe by that time I'll have enough dough for the RB mods that everyone else swears by.
Best part about all this is I have exactly $75 in the cost of a parts bike w/ the pipe and carb as freebies. So you understand why I would like to make it work
I think I'll go back, set my float level stock, use what worked before (50/165)
then play w/ the needle/AS until my bottom end cleans up.
Then lean it out for power and to get rid of smoke.
Maybe by that time I'll have enough dough for the RB mods that everyone else swears by.
Best part about all this is I have exactly $75 in the cost of a parts bike w/ the pipe and carb as freebies. So you understand why I would like to make it work
- fuzzy
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- jlove1974
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looking at sudco's website, http://www.sudco.com/CatalogJPG/054.jpg
a stock jetted PWK38 airstriker should have a #7 slide from the Keihin factory. Wonder which bikes have these carbs? Maybe KTM?
a PWK36 non-airstriker quad vent has a #5 slide, 48-DGJ needle, and jetted 55 and 165....VERY close to my original jetting.
Hmmm that page gives me some ideas. I think I may have answered my own questions. Thanks for nothing y'all
No seriously I joined this site after lurking for a while because of the good advice and knowledge of you all
a stock jetted PWK38 airstriker should have a #7 slide from the Keihin factory. Wonder which bikes have these carbs? Maybe KTM?
a PWK36 non-airstriker quad vent has a #5 slide, 48-DGJ needle, and jetted 55 and 165....VERY close to my original jetting.
Hmmm that page gives me some ideas. I think I may have answered my own questions. Thanks for nothing y'all
No seriously I joined this site after lurking for a while because of the good advice and knowledge of you all
- Julien D
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Well sure, I'd want to make it work as well. If you CAN manage to get it tuned, it might run like a raped ape. That is to say, quite well....
Yes, I have seen KTM's with PWK38's. Is it possible you have a PWK36 and not a modded PWK35?
Hrmmmm. The plot thickens.
If I were in your position, I'd start with what was in there, and work through the jetting systematically one circuit at a time. Pilot then needle then main. Although some like to start with the main and work down. Up to ya!
Yes, I have seen KTM's with PWK38's. Is it possible you have a PWK36 and not a modded PWK35?
Hrmmmm. The plot thickens.
If I were in your position, I'd start with what was in there, and work through the jetting systematically one circuit at a time. Pilot then needle then main. Although some like to start with the main and work down. Up to ya!
- jlove1974
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Ya I am sure it's the part bikes PWK35 that has been modded. It doesn't have quad vents and the outside looks identical to my PWK33 from the 220.
It does run like a raped ape from mid-throttle to overrev w/ the original 165/50/1174 jetting. It's very close to the last RM250 that I rode (2001)...
third gear wheelies + wheelspin. In fact lots of wheelspin (my yard has
some extra drainage ditches now!)
when I get home I am gonna switch back to everything that worked, set
the float level and ride it around. I know the 165 is too rich for any stock-ish KDX. Esp with the temps we have been having this week. Feels like HOUSTON in Carolina!!
I think the pilot would be okay @ 42/45 but that 1173 needle has to go asap.
Wish I had more of an assortment of jets and needles to play with...
It does run like a raped ape from mid-throttle to overrev w/ the original 165/50/1174 jetting. It's very close to the last RM250 that I rode (2001)...
third gear wheelies + wheelspin. In fact lots of wheelspin (my yard has
some extra drainage ditches now!)
when I get home I am gonna switch back to everything that worked, set
the float level and ride it around. I know the 165 is too rich for any stock-ish KDX. Esp with the temps we have been having this week. Feels like HOUSTON in Carolina!!
I think the pilot would be okay @ 42/45 but that 1173 needle has to go asap.
Wish I had more of an assortment of jets and needles to play with...
- jlove1974
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So I changed the needle back to 1174 but raised needle down 1 notch and kept 42/155 then put the airbox lid w/o snorkle back on.
Also, switched floats w/ my stock carb since I couldn't get the float level set because the tang was bent so badly in a curve. I bent it bad try to adjust it.
Looks like I am gonna need some carb parts to send my old one to RB.
It runs pretty good but has to clear it's throat a bit in the midrange like before. Lots more wheelie power w/ the smaller main
I think I am gonna lower the needle back to 3 and maybe 4 and try to clear that up. These factory needles really do suck.
Also, switched floats w/ my stock carb since I couldn't get the float level set because the tang was bent so badly in a curve. I bent it bad try to adjust it.
Looks like I am gonna need some carb parts to send my old one to RB.
It runs pretty good but has to clear it's throat a bit in the midrange like before. Lots more wheelie power w/ the smaller main
I think I am gonna lower the needle back to 3 and maybe 4 and try to clear that up. These factory needles really do suck.
Last edited by jlove1974 on 08:51 am Jun 22 2010, edited 1 time in total.
- fuzzy
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