Testing the 34mm CVK with a/f meter

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  #11  
Old 10-16-2014 | 09:33 PM
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IDRIDR, it looks like the whole thing goes to whether your using DJ stuff or not. From Richards readings, the N1TC(middle notch) + Keihin 125 produce a WOT AFR about like the DJ132/4n - given your near sea level with performance exhaust and lid off ...

Also, my data is with the backfire screen still in. I guess I'll remove it for future testing.
 
  #12  
Old 10-16-2014 | 09:35 PM
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Zomby, that N1TC must present a far smaller cross section to the fuel flow at WOT than the DJ.
 
  #13  
Old 10-16-2014 | 09:40 PM
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It's not the needle. If anything, it's the other way around because I'm running the DJ needle rich, and the N1TC in the middle slot. That, and the needle shouldn't affect WOT at a decent RPM

The problem is that you're comparing apples to oranges. Backfire screen, I bet has something to do with it, but so does your cam mod. The same jetting that works in your bike does not work in mine. I'm betting that putting the lid back on reduced the flow and signal enough that it pulled less fuel and ran better with all that jet.

It's a guess, but when I put the wideband on it, we'll know for sure. It will be interesting to see what I get and compare it to your's and RA's.
 
  #14  
Old 10-16-2014 | 09:49 PM
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You guys with the A/F meters are really gonna sort all this crap out for the rest of us.. I know my backfire screen and MCM will change the signal to the carb over no screen no MCM - but I/we all need a setup, verified with A/F meter or Dyno , to go off of. What ever yall find - if I can duplicate it - I'll run it on the Dyno to check HP/TRQ increases.
 
  #15  
Old 10-16-2014 | 10:10 PM
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Originally Posted by zomby woof
It shouldn't. There's a huge difference in jet size between a 125K and a 132DJ. I believe the DJ is the equivalent of 8 jet sizes bigger.

Here's the comparison chart: https://www.kawasakiforums.com/forum...e2/#post442610
 
  #16  
Old 10-16-2014 | 10:19 PM
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Originally Posted by Klxster
IDRIDR, it looks like the whole thing goes to whether your using DJ stuff or not. From Richards readings, the N1TC(middle notch) + Keihin 125 produce a WOT AFR about like the DJ132/4n - given your near sea level with performance exhaust and lid off ...

Also, my data is with the backfire screen still in. I guess I'll remove it for future testing.
I don't think its a DJ vs Keihin issue. As Zomby said, WOT and sufficient rpm should minimize needle differences. Look at the jet comparison chart.

I do think your MCM mod changes jetting requirements, and your personal jetting setup is not applicable to those who've not done the MCM.

Dirt Bike Magazine has stated many times that they've found no measurable difference on the dyno from screen removal, but that the screens are removed because riders feel it improves throttle response. If you're going to attribute any change in power or torque to removing the screen, then I suggest conducting pulls with the screen, and then without, so you can show the changes are due to the screen only.
 
  #17  
Old 10-16-2014 | 10:31 PM
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Screen removal may affect carb signal, which would alter the jetting.
 
  #18  
Old 10-16-2014 | 11:22 PM
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Keep in mind I am a bit lean for max power with the 125. It should be a 128 or 130.
 

Last edited by Richard Avatar; 10-16-2014 at 11:26 PM.
  #19  
Old 10-16-2014 | 11:49 PM
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Originally Posted by zomby woof
Screen removal may affect carb signal, which would alter the jetting.
Yes, this makes sense to me. But then wouldn't it also affect a/f ratio and dyno results? Which is contradictory to Dirt Bike's claims.
 
  #20  
Old 10-17-2014 | 12:11 AM
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A fact is that Standard Stage 2 uses a DJ128,and needle on the 3rd clip with lid on. (My charts show that setup as way too lean with lid off - up to 16:1.) Now if you discount any variances between the needles, that is, supposedly, like running a Keihin 138 (According to the comparison charts.) - Since Richard saw 11:1 with a Keihin 135, going to a K138 is out of the question.

So I can't be the only one to realize that you cannot compare the DJ main + DJ needle with the N1TC + Keihin mains. Too me it is simple logic based on Richards' data.

Hey guys, to me it really doesn't matter why the N1TC + Keihnin jets offer such delightfully rich mixtures over the DJ stuff- but it is fun to think about.

The MCM tapers off TRQ sooner than standard cam timings.
With lid off and a slip-on near sea level - The increase in HP and TRQ using 132/4n instead of a standard Stage 2 ( 128/3n ) occur in the mid to upper RPM range (from my dyno testing) where standard cam timings stand to benefit most. AFR's show to be as low as 13.5:1 - still too lean but also allowing some altitude forgiveness.
Anyone that meets the criterion should have the chance to feel the power increase you get.
 

Last edited by Klxster; 10-17-2014 at 12:47 AM.


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