mnnthbx

Member
Apr 1, 2003
301
0
OK, I got my new woods pipe installed today. It went on easy. Seems to be built well. Fit up well enough. Sounds good. Only slightly louder, but much crisper sounding.

It has a much improved mid, with no loss on top. I auctually seems to come on a few hundred RPM later of the bottom though. No doubt due to my lack of jetting greatness.

Question time.
(*Disclaimer* I have no good area for a plug chop, and test by feel. I am good mechanically, but fairly new to dirt bike carbs. I have a long history of modding PWC) It has 45, 155, 3rd clip in it now. Airbox mod, pipe, silencer only.

At walking speed, in second, if I gap it, it is soft just for a second. (again, it feels like the band starts a bit higher that the stocker). Half throttle and below is quick and clean.

Now, looking over the options, FMF's site says to use the jetting I am now, but to use a R1173K needle in place of my stock R1174K. I'm not sure what this will effect????

My gut says to try one size lower main, (as the site references a 155 or a 152 for my application), but in my ignorance, it seems to me, that a aftermarket pipe would flow better, processing more fuel on the main, not less.......

I only think of the main because, if I'm going slow in second, and want to lift the front quickly of a log or rut, if I gas it too around 1/2 throttle, it seems to pop cleaner and quicker than if I gap it full.

Anyway........ should I try a smaller main first, move the clip position first, or try the new needle first. Thanks for your help. I tried to gather all the info I could before I wrote all the blabber.
 

mnnthbx

Member
Apr 1, 2003
301
0
One other thing, I already was running the 45 pilot, 155 main, 3rd clip before the pipe install, and the bike ran great. Common sense tells me a pipe would make the bike a bit leaner if the jetting stayed the same, right?

The problem isn't TOO bad by the way. The bike is rideable as is. Just want it to be right.
 

DRECKFRESSER

Member
May 29, 2003
41
0
What year? What size? Check the plug!! If your getting a bog when you crack the throttle you might be a bit lean. Happend to mine. (03 kdx 200 airbox mod and boysen reeds) I also put the woods pipe on mine. I just moved the needle clip down one and was good to go.

good luck
 

KDXFreestyle

Damn Yankees
Member
Nov 19, 2002
645
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hmm.. that brings up a question for me then... if my bike seems to be boggy a littl ehwen my throttle is cracked, could my bike be running lean? I have a 2003 KDX 200

FMF Power Core 2 silencer (packing seemed to be spoogy when I checked it), Stock jetting, airbox mod, 13/47 tooth sprocket combo, and a NGK b8es plug (which is black and tan)

Thanks
 

mnnthbx

Member
Apr 1, 2003
301
0
Sorry. It's a 03 200, FMF -35 woods pipe. Air box mod. FMF silencer. Motul 40:1

I tried a 158 main today. Seemed a bit rich, so I'll go back to the 155 and try the new needle. Here's the problem.

FMF's site a 1173K needle for every recent year 200 except the 2003, for which they recommend the the 1173L. (there needle of choice for the 220). Since the 200 is unchanged, I wonder if it is a typo on there site??????

Should I use the L or K needle?
 

kdx633

Member
Aug 12, 2003
127
0
I had the same problem with 01 220,did air box woods pipe turbine core fmf other than that stock.klotz techniplate 32:1etc. throttle response would stumble at low rpm.rideable but very annoying when needing to lift front wheel at slow speeds.when temps where below 60f it would run better.leading me to believe it was rich at low speed.throttle chop at low throttle position several times confirmed this.changing pilot jet down 1 size from stock [dont remember # im at work screwing around here and dont have access to my bike notes]helped out alot.after that was complete did wot chop only to find a lean condition.bumped main up 1 size over.again big difference did away with flat feeling up top. needle position changes with temp.70 or above 3rd from top 70 or below 2nd from top. around 55f move back to stock pilot
 

mnnthbx

Member
Apr 1, 2003
301
0
Since I only feel the bottom end weakness when I'm at walking speed, and I quickly give it FULL throttle, I assumed that was the main jet. Even though the ngine speed is low, the throttle position is full. That is what determines what circuit I'm on right???

Thank you all for your help and comments.
 

John Harris

Member
Apr 15, 2002
552
0
Drop your needle to second clip from top. If this does not do what you need, then try one size leaner on pilot. I think it sounds like too rich coming off the pilot circuit. Good luck.
 

KDXFreestyle

Damn Yankees
Member
Nov 19, 2002
645
0
663... would this be the same with a 200? my bike falls flat on top, as you say yours did, and it boggs if Im in 2nd.. going about 5 mph, mabey 10, then just pin it.. it seems to have a slight bog. I think im mixing at 52:1 gas mixture ratio with 93 octane. thanks
 

kdx633

Member
Aug 12, 2003
127
0
i know the 200 is a slightly different animal however the carb/pipe theory of operation is the same.i'm sure you have read all do's and don'ts about fuel etc.but 52:1 sounds very lean fuel/oil mixture,not to be confused with fuel/air mixture.52:1 will make f/a mixture very rich.initially i figured my problem was related to excessive air box vacuum.method of proving this right or wrong was to remove lid all together and air filter [just a couple minutes for testing ] changed trouble slightly,not enough to make it feel spot on.so on to next phase was pilot jet.the idea that it was too rich bog and not lean bog was the puff of smoke it would emit for a second or two after slow speed ride then fast twist on throttle when the engine could burn off excees fuel.I just assumed the flat spot up top was a virtue of the pipe and it is to a certain extent,however after pilot thing was sorted out the flat spot got bigger thats when did wot check,found lean etc.and now bike pulls much harder up top as well.one last thing and i promise to quit rambling,with the stock pilot bike would cold start on 80f day w/o choke again pointing to pilot/rich thing.with the kdx wonderfull front end the stumbling engine is just a ton of fun,is'nt it ?
once cleaned up you will be pleasantly surprised.each bike is different use it for w.i.w.
 

KDXFreestyle

Damn Yankees
Member
Nov 19, 2002
645
0
so I should mix my gas to say... 40 to one, or w/e th emixture is with golden spectro? (4 gallons to 1 bottle instead of 5 gallons, which is 52:1)
 

wanaride

~SPONSOR~
Jul 18, 2003
492
0
FWIW, I have an 03 200 and I have the same flat response when moving slowly in 2nd gear and I rip open the throttle; I've been working on the jetting since July when I bought it and it's still not "there". Main=152, pilot=40, needle=3rd from top, AS variable, airbox mod and stock pipe. I twist the throttle open and there is a delay of about a second before the revs start to build. Based on what I've read, I still think I'm running rich, but to tell you the truth I'm not really sure.

The engine rev response is delayed (in 2nd gear, slowly moving, and I rip open the throttle) until I get the AS to 2 turns out, then I hear the "booh-wah" and it sounds like the engine is going to die, so I presume I'm too lean at that point (and too rich from AS=0.5-1.5 turns).

I have read many reports of "Oh yeah, my stock bike goes vertical when I twist the throttle open in 2nd gear", but try as I might, I just can't get there.

I ordered the FMF woods pipe and TCII silencer but have yet to install them. If I figure anything out that is useful, I'll let you know.
 

Braahp

~SPONSOR~
Jan 20, 2001
641
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mnnthx..... I ride at same altitude as you and same places sometimes. I run stock jetting/needle.... except for needle in 2nd clip from top. And I'm afraid mine is almost boredline lean sometimes. Airbox lid removed and gnarly pipe/PC II silencer. 13/50 gearing. Absolutely rips! Starts great. Rarely even touch airscrew. I think maybe some of you guys are lean and not rich by the way you are describing. Just for the heck of it try a BR8EG plug instead of the ES and see what happens. Don't ask me why but mine runs a whole lot better with this plug. These carbs are so simple to jet and not near as temprimental compared to pwc's. No pop-off and gazillion jets x 3. Keep it simple. Try the plug you will be surprised!
 

mnnthbx

Member
Apr 1, 2003
301
0
Wanna, thanks for the input. I'm somewhat ignorant, but I think the air screw will only effect from idle to 1/4 throttle, so when me and you are hacking the throttle open, the air screw would have little or no effect in regards to our hesitation.

Just based on what I see around here (and I realize each bike is different) your jets sound to be on the lean side.

For now, I am running a woods pipe, air box mod, FMF silencer. 45 pilot, & a 155 main. I just put a 1139N needle in at #3 clip, and it didn't help. I moved the new needle, one clip richer, and it seemed to take a bit of my lag away.

Now it's a tiny issue. In reality, I sometimes can get it to hesitate if I try, but I don't think it will while in the woods under normal use.

Good luck with yours, and keep us posted.
 

KDXFreestyle

Damn Yankees
Member
Nov 19, 2002
645
0
speaking of this... how do you find a good starting point for jetting, if you put more than one mod on your bike? For example... I will be putting on a Pro Circuit Pipe with Pro Reeds. How will I know where to start?
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
mnnt:
You have the basic idea down. Don't forget the basics and you'll get your bike sorted out just fine.

Keep in mind the overlap nature of the circuits in the carb, one that is 'not' in play in a particular throttle range can still screw things up if it's off. Things like 'hit' and 'bog' are likely issues of transition from one circuit to another. It's not a simple thing to have all the circuits run as they should..it's easy, but it's not simple.

Example: While the main isn't 'used' at the bottom end of the throttle range, it can most certainly effect performance IN that range when it's out of whack. Guaranteed. So...having an out-of-sorts lower range response doesn't necessarily mean you need to 'fix' a lower range circuit.

Keep after it..you'll get it sorted out and learn a whole lot about your scooter in the process.

:think: An 1139? What diameter would you say that is?
 

mnnthbx

Member
Apr 1, 2003
301
0
Sorry, I meant 1173.

Speaking of lean......... after my bike is good and hot, I can touch the cylinder for a three count, so I don't think it's too hot. And it still gives me some decent smoke at a blip of the throttle.

I looked at the plug after 30 minutes today (riding around a small farm, no place for a plug chop) and it was light brown... for what evr thats worth.

Also, the bike has backfired twice when I shut it off since I put on the pipe and new jetting. Mean anything?
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
Bike flatulence ain't no big thing. I mean.....really.... when it's been stinking up the environment with petroleum distillate products for HOURS..what's a little gas?

p.s.
Do try an 'eg' plug.

Yeah...I get my '39s' and '73s' mixed up all the time! ;)
 
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