Exhaust Mod
#51
09-06-2016, 11:28 PM
IDRIDR, while the "exact" AFR for best power is disputable,(and rightly so as the exact composition if the fuel you burn determines it) you'll find most numbers fall between 12.5 and 12.8 to one..
#52
09-10-2016, 10:31 PM
Join Date: Aug 2016
Location: NE Ohio/Northern Michigan
Posts: 49
In case anyone has concerns about doing the Dyno Jet kits yourself. I can tell you that although I have pretty substantial mechanical experience (backyard mechanic), I had little to no carb experience and was intimidated by doing this mod. From the help of this forum, I have now pulled my carburetor 4 times in the last week and a half and have been playing with different Dyno Kits recipes that I've found in here without any hiccups (yet). I can confidently do this job in about an hour and a half at this point now. Everything you need to know is in the forum somewhere to do this job.
Oh and the performance gains are huge.
Oh and the performance gains are huge.
#53
09-10-2016, 11:13 PM
Houston has become our newest tuner and is testing and Dyno'ing carb setups -
See the thread - https://www.kawasakiforums.com/forum...klx250s-44229/
See the thread - https://www.kawasakiforums.com/forum...klx250s-44229/
#54
09-10-2016, 11:55 PM
Join Date: Aug 2016
Location: NE Ohio/Northern Michigan
Posts: 49
Houston has become our newest tuner and is testing and Dyno'ing carb setups -
See the thread - https://www.kawasakiforums.com/forum...klx250s-44229/
See the thread - https://www.kawasakiforums.com/forum...klx250s-44229/
Yes my friend I believe you have opened Pandora's box.
Have I mentioned how thankful I am of all your help and tremendous education you've been providing me?
Well just in case, thanks again!
#57
09-12-2016, 08:46 PM
Join Date: Jul 2011
Location: middle tennessee; 600ft asl
Posts: 547
DRM:
Your situation is actually really simple - grab your K152 main jet and install it (if your near sea level). If you are at elevations of 2k or more, you'll have to calculate the K152/DJ140 comparable. Use the instructions from my "DGR slipon" thread below or respond with your elevations..
While it's probably hard for some to grasp, nothing "good" happens with the CVK until the main jet is correct for proper WOT fueling above 7k RPM. After that, the clip position is used to fuel the midrange properly for: 1. The best throttle response at all RPM's. 2. The best power levels 3.5-7k rpm @ WOT.
Just know that the needle controls part throttle operations at ALL rpm's. And, when you snap and hold WOT, power levels from 3.5-7k rpm.. And this is fine tuned with the clip position.
I think your current 3N (third notch down from the top) will be perfect or very, very, close.
Now that being said, I only know what proper main jets to use if running lidless with a slipon or full performance exhaust system, for running with the lid sans snorkel or lid+KDX snorkel or lid+stock snorkel, we have to trust DJ. Which is fine just as long as you don't wonder why they include a DJ132 main jet, in the kits, with NO information about its' use ! They include a logical collection of jets up to the DJ128, with instructions of their use - then there's that oddball DJ132 in there! With no instructions about it's use !... I figure they realized, at a much later date, that if you add a slipon, or, lord forbid, a full exhaust system, the DJ128 isn't big enough. So they threw in the DJ132 without directions in order to avoid having to invent a "stage III" recipe and/or admit that the kits are not well designed for performance exhaust mods..
Your situation is actually really simple - grab your K152 main jet and install it (if your near sea level). If you are at elevations of 2k or more, you'll have to calculate the K152/DJ140 comparable. Use the instructions from my "DGR slipon" thread below or respond with your elevations..
While it's probably hard for some to grasp, nothing "good" happens with the CVK until the main jet is correct for proper WOT fueling above 7k RPM. After that, the clip position is used to fuel the midrange properly for: 1. The best throttle response at all RPM's. 2. The best power levels 3.5-7k rpm @ WOT.
Just know that the needle controls part throttle operations at ALL rpm's. And, when you snap and hold WOT, power levels from 3.5-7k rpm.. And this is fine tuned with the clip position.
I think your current 3N (third notch down from the top) will be perfect or very, very, close.
Now that being said, I only know what proper main jets to use if running lidless with a slipon or full performance exhaust system, for running with the lid sans snorkel or lid+KDX snorkel or lid+stock snorkel, we have to trust DJ. Which is fine just as long as you don't wonder why they include a DJ132 main jet, in the kits, with NO information about its' use ! They include a logical collection of jets up to the DJ128, with instructions of their use - then there's that oddball DJ132 in there! With no instructions about it's use !... I figure they realized, at a much later date, that if you add a slipon, or, lord forbid, a full exhaust system, the DJ128 isn't big enough. So they threw in the DJ132 without directions in order to avoid having to invent a "stage III" recipe and/or admit that the kits are not well designed for performance exhaust mods..
Thanks klxster!
#58
09-12-2016, 09:01 PM
DRM - latest, up-to-the-moment findings with Houstons4's use and Dyno test/chart of the 2206 kit, indicate that, at your earliest convenience, please reset your clip position to the top (1N). You will need to super glue the washers together and rest them on top of the clip - as 1N is so close to the top end of the needle..
While you have a drilled slide on a stock spring, he is now running 1N with a stock lift hole and stock spring - he reports more everywhere over 2N+lighter spring.. His latest chart indicated some overfueling of the midrange and 1N is important to control this problem..
What you should notice is improvements below 7k in throttle response and power levels. There is also likely an increase above 7k as the overfueling could be causing a loss of hydrostatic pressure due to fuel depletion in the bowl from the overfueling. This is my take on the somewhat erratic AFR's on Houstons' bike, 7800-9500 RPM (on his latest chart).
Please follow the Dyno Testing thread on Houstons' bike as it directly pertains to yours.https://www.kawasakiforums.com/forum...klx250s-44229/
While you have a drilled slide on a stock spring, he is now running 1N with a stock lift hole and stock spring - he reports more everywhere over 2N+lighter spring.. His latest chart indicated some overfueling of the midrange and 1N is important to control this problem..
What you should notice is improvements below 7k in throttle response and power levels. There is also likely an increase above 7k as the overfueling could be causing a loss of hydrostatic pressure due to fuel depletion in the bowl from the overfueling. This is my take on the somewhat erratic AFR's on Houstons' bike, 7800-9500 RPM (on his latest chart).
Please follow the Dyno Testing thread on Houstons' bike as it directly pertains to yours.https://www.kawasakiforums.com/forum...klx250s-44229/
Last edited by Klxster; 09-12-2016 at 11:56 PM.
#59
09-13-2016, 12:09 AM
Also DRM, we do not have data concerning slide functioning with drilled lift hole + stock spring. This means that I do not know exactly when your DN0352 is lifted to its' "fast taper". But know that when this "quick enrichening" taper is lifted "out of the hole" (the Needle Jet) your AFR will go richer in a real hurry.. The good news about all this is that DJ designed the needle/drilled lift hole/stock spring to work together with the lid off . Lets hope that this enrichening occurs at an RPM above 6K @ WOT.. If you want to discuss and DynoButt test this more, PM me..
#60
09-13-2016, 02:07 PM
Join Date: Jul 2011
Location: middle tennessee; 600ft asl
Posts: 547
I'm gonna be a little slow testing this... I'd like to get some solid ride time on the current config so I'll be able to tell a difference going to 1N. Thanks for the help and insight!