Jetting help needed

Got questions? We got answers....
Post Reply
User avatar
G22inSC
Supporting Member I
Supporting Member I
Posts: 513
Joined: 10:23 pm Jul 24 2006
Country: United States
Location: South Carolina

Jetting help needed

Post by G22inSC »

I have begun trying to jet my 05 200 and can't seem to get it right. Either I am to cautious or I am missing something. Location is Upstate of South Carolina with temps around the 80's now. I have a complete PC exhaust with the air box lid removed. I currently have a 42 pilot, stock needle in 2nd from top slot and 155 main. I am using 32:1 Mobil synthetic with premium pump gasoline.

Here is my problem. I still have a little spooge and it seems to be too rich (excessive smoke) at low throttle. I have used a tach trying to find the max rpm on the pilot jet by turning the air screw but the rpm's just keep increasing. Is that because I am still too rich on the pilot or am I missing something. I have worked down to the 42 pilot and am not sure if I should go to a 40 or not. I can't seem to find the spot where the rpm's will increase/decrease. I can't seem to notice any real bog with closed to wide open throttle; however, this is my first bike and don't really know what it should be like jetted correctly. If I crack the throttle wide open from closed the front wheel will sometimes slightly lift if the traction is good.

I think I am pretty close on the other settings; however, I do not have an area close by to do throttle chops to check the plug. Sorry for being so long winded. I am supposed to go to Durham Town this weekend with a couple of buddies and was just trying to be in top shape bike wise. Thanks for any help.
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

Gallery

2005 KDX200 Bike Profile
User avatar
m0rie
Supporting Member I
Supporting Member I
Posts: 2220
Joined: 10:25 pm Nov 29 2004
Country:
Location: Crescent City, CA

Post by m0rie »

That sounds about right for a stock needle and your mods. Long term i'd look at switching out to a CEL needle or getting your carb worked over by RB. Short term i'd just ride it and have fun!
1989 KDX 200
2007 TTR-50E
User avatar
G22inSC
Supporting Member I
Supporting Member I
Posts: 513
Joined: 10:23 pm Jul 24 2006
Country: United States
Location: South Carolina

Post by G22inSC »

mOrie
Does that mean you would put a 40 pilot in or just leave the 42 pilot in place?



Does anyone know why I can only get an increase in rpm's by turning the air screw from 0.5 turns out to more than 3.0 turns out? It just seems like I am missing a key point somewhere. I also noticed on the last adjustment attempt that I had gas flowing out of the carb vent line once I had the air screw more than 2 turns out. Any ideas?
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

Gallery

2005 KDX200 Bike Profile
User avatar
m0rie
Supporting Member I
Supporting Member I
Posts: 2220
Joined: 10:25 pm Nov 29 2004
Country:
Location: Crescent City, CA

Post by m0rie »

Sounds like your float is not set correctly if your peeing gas. You can give a 40 pilot a try but I'd bet that it will be on the lean side with 80 degree temps.
1989 KDX 200
2007 TTR-50E
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Re: 'I have used a tach trying to find the max rpm on the pilot jet by turning the air screw'

That's not how the slow speed circuit is set (max rpm). It's common knowledge to do so, and it's incorrect.

Set the air screw using throttle response as a guage. Basically..one gear too high (2nd, walking speed), quick wick from off idle to about 1/2 throttle, adjust air screw to best response. You're working toward NO lag, hesitation, blurb or 'booo-whaaaa'.

Never...NEVER jet by spooge. Not ever, even. Jet to best response, best tune.

Never jet by smoke, either. The two (smoke and tune) are not necessarily even related.

Why did you choose 32:1?

Chances of engine damage due to too small a pilot are about nil. Try a 40 and see if throttle response improves. This is about the time of year to be on the edge of jetting changes..it can be real cool to very warm on the same day.

Re: '...why I can only get an increase in rpm's by turning the air screw from 0.5 turns out to more than 3.0 turns out?'

Sorry in advance, but specific wording (and thus meaning of them) is something I have a particular problem with...but...the word 'only' renders the question puzzling. You are expecting to get an increase in rpm from something other than turning the air screw out? Or...why do you not get an increase beyond three out? Or...why do you not get an increase from zero-.5 out?

The specific answer to your question is, 'Because that is how the air screw works.' Your description of its operation is what it is supposed to do. More commonly the complaint is, 'Why do I NOT get an rpm increase when I adjust my air screw from .5 to 3.0 out?'

Oh...which PC pipe? The Platinum II will use a smaller jet set than the Platinum pipe. Same is true for the FmF profiles (torque/rev respectively).

Carry a spare plug or two with you. If during your ride you get any undue 4-stroking (like on the gas after a long idling period), your pilot circuit is too rich. Not all 4-stroking is bad! Mid throttle, no-to-very light load, a skippy 2-smoke is a happy 2-smoke!

YiPpY SkIpPy!! :wink:

Long winded post? Not to worry...you're not even close!!!

Cheers!

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
2001kdx
Supporting Member I
Supporting Member I
Posts: 1522
Joined: 08:36 am Sep 23 2006
Country:
Location: Town of Montgomery, NY

Post by 2001kdx »

"4-stroking" Is this when you use 1/4 or 1/3 throttle on flat ground and the bike is off and on, like "bidibidibidibidi" instead of a steady-sounding bike? Sorry for my bad bike noises :mrgreen:
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

I'd guess that 'noise' to be correct. Actually I have no clue what bidibidibidi sounds like...kind'a auctioneer-like I would suppose.

It's a 2-smoke firing every 720º (like a 4-stroke) as opposed to every 360º as a 2-smoke generally should.

...º as in cranky rotation.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
G22inSC
Supporting Member I
Supporting Member I
Posts: 513
Joined: 10:23 pm Jul 24 2006
Country: United States
Location: South Carolina

Post by G22inSC »

Just to clarify I was trying to find the point at which max rpm's were attained to then check to see if the pilot was too large or small (depending on how many turns out the air screw was at that point). Once I had the correct pilot, I would then jet for best off idle throttle response. Is this logic incorrect. I thought as you back the air screw out, the rpm's should increase to a point and then begin to decrease. That is what I can't find. The rpm's just increase the more I turn the air screw out. I did not know if that meant I was still to rich on the pilot or not.

I chose 32:1 because that is what the factory specs call for. Should I be using another ratio with Mobil synthetic? My pipe is the PC Platinum II.
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

Gallery

2005 KDX200 Bike Profile
User avatar
2001kdx
Supporting Member I
Supporting Member I
Posts: 1522
Joined: 08:36 am Sep 23 2006
Country:
Location: Town of Montgomery, NY

Post by 2001kdx »

>|<>QBB<
canyncarvr wrote:I'd guess that 'noise' to be correct. Actually I have no clue what bidibidibidi sounds like...kind'a auctioneer-like I would suppose.

It's a 2-smoke firing every 720º (like a 4-stroke) as opposed to every 360º as a 2-smoke generally should.

...º as in cranky rotation.
Yeah - How would you type a 4-stroking KDX? I think by "bidbidibidi" you can understand that I'm talking about the bike firing every 720 D instead of a smooth 360 D.

And How the heck are'ya makin the degrees thingy?
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Re: 'I thought as you back the air screw out, the rpm's should increase to a point and then begin to decrease.'

Generally (meaning commonly) with the OEM carb the idle speed will increase as the AS in turned out to a point, further than which the idle speed will not change.

For general interest: The OEM carb is not real sensitive AS-wise, generally. Also, it's not a matter of huge speed changes, either...neither do those changes happen with the speed of a throttle twist. Yank the AS around turns at a time with split second timing and you likely won't notice anything happening.

Generally accepted premix mixing: Use the spec listed for the oil you use. In lieu of that, second choice is bike mfg. rec.

The oil I use specs 40:1, so that is what I use. I did try 32:1 (given the fact that a 2-stroke will make more power the more oil..lower number ratio.. is used. To the point of not being able to light the mix anyway), and it did not work well.

A btw, but in my Banshee (350cc twin) 32:1 is far superior to 40:1 performance-wise. Mfg. spec I believe is 24:1.

How? First off, I can't believe it took this long for someone to ask. Part of the fun of putting º in there was waiting for someone to ask about it.

...I've been waiting for a few years now...

Look in your character map for your chosen font. Likely you will find <alt>0186 will display a º.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
G22inSC
Supporting Member I
Supporting Member I
Posts: 513
Joined: 10:23 pm Jul 24 2006
Country: United States
Location: South Carolina

Post by G22inSC »

I am still missing something.



Quoted from the jetting guide:

"As already stated, start with the pilot circuit. Turn the airscrew all the way in, then turn it out 1.5 turns to start. Start the engine, and turn the idle

screw in until you get a slightly fast idle, or hold the throttle just barely cracked, to keep the engine idleing. Turn the airscrew slowly in, and then

out, until you find the point where the idle is fastest. Stop there. Do not open the screw any farther, or your throttle response will be flat and

mushy, and the bike may even bog. This is only the starting point, we will still have to tune the airscrew for the best response.

Now is the time to determine if you have the correct pilot installed in your carb. The airscrew position determines this for you, making it very

simple. If your airscrew is less than 1 turn from closed, you need a larger pilot jet. If it is more than 2.5 turns from closed, you need a smaller pilot jet."


This is what I can't get to work. As I turn the air screw out, the rpm's increase. The rpm's continue to increase even to the point of turning the air screw out enough to where it will fall out. Does this mean that I am still to rich (need to install smaller) on the pilot jet?
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

Gallery

2005 KDX200 Bike Profile
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

That's the procedure.... I don't think you missed a thing!

What pilot is in there now?
*** 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!!! "
User avatar
G22inSC
Supporting Member I
Supporting Member I
Posts: 513
Joined: 10:23 pm Jul 24 2006
Country: United States
Location: South Carolina

Post by G22inSC »

PC exhaust, no air box lid
BR8ES plug
good reeds and topend
32:1 Mobil synthetic (possible Amsoil soon at unknown ratio)

Maybe 1000' above sea level, 80's - 90's temp

42 Pilot
Stock needle (2nd from top)
155 Main


How come I can't find the point where the rpm's go from increasing to decreasing or vice versa?
'05 Kaw KDX200 ('00 KX125 forks / '02 RM125 Showa "K2" shock)
'14 Yam YZ125(x) (oldest boy's)
'22 Yam YZ125X (youngest boy's)
'17 Yam YZ85 (soon to be FOR SALE)
'10 Honda Recon (wife's)
'08 Kaw KX65 (Sold)
'07 KTM 50SX Sr. (Sold)
'09 Yam PW50 (retired)
'97 Kaw KX250 (Sold)

Gallery

2005 KDX200 Bike Profile
saddletramp
Supporting Member
Posts: 275
Joined: 04:47 pm Oct 06 2006
Country:
Location: washington

Post by saddletramp »

I don't ever listen for a decrease in rpm, usually the increase is subtle and if you turn the a/s to fast you miss it. I start at about half turn out from full closed turn slowly with the throttle just above idle. As I hear the rpm increase I stop, then I will turn out just a smidge more and will always get another slight increase in r's.
2000 KDX 200 97 KX 125 Front End
1996 CR 250
03 RM 65 2000 YZ 80
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

The academics of the issue are neither important nor pertinent...nor can I answer your question.

The RPM change idea is simply a tool to use as a tell-tale for the low speed circuit. It's the result of using the tool that is important.

You are probably pretty close with 42/155 at sea level. Humidity (a lot of it in the East) will make a difference for sure.

Maybe I already said this (I'm sure I've already said it already some other place), but you aren't likely to damage anything by running too lean a pilot. So change it and see what happens! TEST a 40 to see if throttle response improves or not.


There are some phrases used that make me think I probably still don't understand the situation, though. 'How come I can't find the point where the rpm's go from increasing to decreasing or vice versa?' as an example.

RPM will NOT go from 'increasing' to 'decreasing' anywhere with the same direction of rotation of the screw.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
Post Reply