A Little Help with Jetting?

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  #11  
Old 09-06-2015 | 03:45 AM
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Originally Posted by MattyTracks
I'd try a leaner pilot/AF setting and/or 1 notch leaner on the needle.
For the pilot it's either the stock one ore the 40 with the mixture screw turned in. I'll wait until the 300 exhaust is on before I play with the jetting as you suggested. I hate trying to position that diaphragm.
 
  #12  
Old 09-06-2015 | 03:47 AM
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With the air injection removed and capped off, it is strange that you get decel pops with 2.5 out on a #40 pilot jet @ 1500ft... Makes me wonder if your pilot system is clogged up / not working properly.. If so, it would also explain sluggish throttle response below 4K..
 
  #13  
Old 09-06-2015 | 03:50 AM
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3N is the 3rd notch down from the top - it is the standard setting for the needle.. 3N provides a known "baseline" fueling curve for a properly sized main jet..
 
  #14  
Old 09-06-2015 | 03:51 AM
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Originally Posted by Klxster
More on the idle to 4k thing...
I assume you have bad throttle response in this range. The fuel screw, once set correctly, should improve low RPM throttle response - this is assuming your fuel level (float level) is within spec.. You certainly should verify float level is 15mm (plus or minus 2mm)..
I'll play with the fuel screw tomorrow and check the float level. I could see how it could be out. The carb has never been apart accept for my work and the bike has very low mileage but I'll still verify.

Thanks for all you suggestions.
 
  #15  
Old 09-06-2015 | 03:53 AM
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So, in summary, reset the fuel screw to just "out" from the lean idle drop, and reset the needle to 3N.
 
  #16  
Old 09-06-2015 | 04:44 AM
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Originally Posted by Ruggybuggy
Opps! Thought I had everything. 1,500 feet. The DJ kit is not an option for me. No local supplier, Im in a remote part of Canada but we do have a Kawi dealer 200 miles away so l bought the Kawi jets.
I ordered almost all my parts through http://www.canadasmotorcycle.ca/

free shipping and they use Canada Post, so if you can get mail in your house, you can order from them.

Never had an issue so far.
 
  #17  
Old 09-06-2015 | 04:48 AM
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Originally Posted by pwjm
I ordered almost all my parts through http://www.canadasmotorcycle.ca/

free shipping and they use Canada Post, so if you can get mail in your house, you can order from them.

Never had an issue so far.
Thanks for that, never considered them for the DJ kit. I'm already into the Kawi parts now and I've drilled my slide so no DJ kit for me.
 
  #18  
Old 09-06-2015 | 04:51 AM
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No worries, the Kawi parts are not at all much different than the DJ parts. The main jet sizing doesn't line up though so you might have to experiment a bit.
 
  #19  
Old 09-06-2015 | 07:23 AM
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FYI: Here is the minutia..

The MCM likes extra fueling from just off idle to whatever max RPM the airbox config and exhaust will allow. The K130 may be correct or very close for Ruggy (not necessarily you, the reader). The N1TC at standard 3N should keep the low and mid RPM AFR proper with the larger main jet - it has a "fat" straight section dia (helps to keep low to mid RPM proper with the big main jet) but tapers quickly (goes richer quickly as RPM's rise) - all of which will serve to maintain a proper AFR while allowing the MCM to drink aggressively @ WOT.
 

Last edited by Klxster; 09-07-2015 at 01:29 AM.
  #20  
Old 09-07-2015 | 01:52 PM
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Originally Posted by Ruggybuggy
Opps! Thought I had everything. 1,500 feet. The DJ kit is not an option for me. No local supplier, Im in a remote part of Canada but we do have a Kawi dealer 200 miles away so l bought the Kawi jets.
Food for thought...

If you're willing to spend $80 to never rejet your carb again, put the lean main back in or even a 125, and get a Dial-A-Jet. I'm at 1000ft elevation and running clean on both my bikes. Went to WV with the big bike and ran clean up in the mountains a few thousand feet higher.

I have run them for the past 20 years in bikes both stock and modified. The KLX650 went with a cut lid, big bore piston, and pipe without any jetting changes, although it could use a bigger pilot since the DAJ works with the slide/needle/needle jet/main jet circuits, not the idle circuit.

I did the KLX300 jetting on my 250, as did my brother, and installed the DAJ, smoothing out the power delivery - I also have the MCM mod. The bike pulls decently over the whole range - for a 250 (riding the 650 kind of jades me on the power). The carb only needed to be apart once to put in the 300 brass, nothing else from there.

On the Thunder products site go read the media comments. The ATV and Snow mobile industries have taken to it whole hog, where the motorcycles are stuck in old school brass. Fact is I had them in a customer's Honda Nighthawk S in place of jetting when he put a Kerker on it back in 1986. Worked perfect without ever removing anything but the gas tank to install them.

Take a serious look, especially if you go into higher altitudes on any frequency. It is a fuel adder powered by the vacuum draw and acoustics of the intake. You jet lean for the high elevation with the brass, then let the DAJ fill in the fuel mix when at lower elevations. It will fill in leanness, doing nothing when running rich - it only works when lean, so you jet lean.

Seems a bit steep to spend the money, but how much would it be worth to not have to take a carb off for jetting again? Plus if you go to a flat slide you can use it with that carb too. Same kit is in both my 250 and 650, the 250 is eventually going to a flat slide and it will be jetted lean and the DAJ in it.
 


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