Carb Adjustments

Started by Josh_TN , Jun 17 2008 06:08 AM

46 replies to this topic

  • Josh_TN

Posted 28 July 2008 - 07:45 AM

#41

Crazed Geezer said:

I have practically the same exact settings on my '08, except my A/F screw is 1 1/4 turns out, and I ground my header weld. I left my screen in for the same reason (mice!) and my altitude is only 150 ft. higher. Runs great. Seems like we both arrived at the same tune so that tells me we're probably doing something right. :ride:

I do more gravel county roads than pavement and run in 3rd gear a lot so my mileage is a bit less at around 48 mpg, but I bet if we traded bikes and rode them around our own stompin' grounds the mileage and performance would be the same on either one.

;)

I'm glad to know that there is at least one other person getting around the same results.
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  • JibJab

Posted 31 July 2008 - 01:59 PM

#42

Josh_TN said:

GsVs,
My set up is now a .030" shim.  THe snorkel removed, screen still  in(I live in the stix and we have mice), and the mixture screw aproximately 1.5 turns out from seated.  I am around 450 feet above sea level.  Hope this helps.  ALso worth noting that the mpgs are based on normal riding and no more than 65 mph and a good mix of city and highway commuting.  ALong with some twisty backroads.  Hope this helps.

Josh,

Just to clarify your setup (I'm new to carb stuff), did you simply add a .030 shim washer to the stock setup or is the total shim you're using .030 (i.e. you removed any existing washer(s) from the stock setup and replaced it with the .030 washer)? Also, where did you get the washer from?

Thx

  • Josh_TN

Posted 01 August 2008 - 05:58 AM

#43

JibJab,

You will need to get a few #4 machine screw washers.  Probably have to go to a small mom and pop type hardware store.  Home Depot and Lowes don't carry anything that small.  Use a caliper if you want to get real picky.  Otherwise a #4 washer will be really close to .030".  Remove the plastic washer on the needle.  place the #4 stainless washer on the needle and then reinstall the factory plastic washer.  make sure that they are tight together and reinstall.  If you want you can drill the slide out while you have it apart.  then drill out the brass cap covering the mixture screw.  adjust out and ride!

You should be able to find a few pics on this site.  It is not as hard as it sounds.  Good luck.

  • shrubitup

Posted 12 May 2009 - 08:23 AM

#44

Woo-hoo! Found the basics thread for dummies! :ride:

Was afraid to shim my needle so I bought the KTM LC4 needle and bent it instead because I didn't use the factory plastic washer beneath the clip. :cry:

So, removing the snorkle - shimming the OEM needle with the #4 washer- and adjusting the fuel screw will all result in more air and fuel. ProCycle is using a 137.5 main and Eddie Sisneros (TT jetting expert) says to use the next size smaller pilot.

Has anyone done the above described mods AND also both reduced their PJ and MJ too? If so, the bike would be slightly leaner on those circuits and then richer on the needle where most of the carb is doing its work for most of the uses this bike sees. Agree? :smirk:

If so, richening the needle (via shimming), leaning the PJ slightly, richening the fuel screw, leaning the MJ slightly, and snorkle removal ought to result in less overall MPG change than just the usual mods w/o also adjusting the MJ and PJ - right?

:excuseme:

  • GsVs

Posted 05 June 2009 - 05:37 AM

#45

Hey shrubitup ...

Good theory ...

"" If so, richening the needle (via shimming), leaning the PJ slightly, richening the fuel screw, leaning the MJ slightly, and snorkle removal ought to result in less overall MPG change than just the usual mods w/o also adjusting the MJ and PJ - right?  ""



have you heard from anyone ??

GsVs

  • CaptTurbo

Posted 05 June 2009 - 01:51 PM

#46

I don't think reducing the main jet is a good idea. Removing the snorkel, shimming the needle, and adjusting the mixture screw is proven and works well. It's all about the A/F ratio. You do NOT want to get too lean.

  • shrubitup

Posted 05 June 2009 - 03:49 PM

#47

CaptTurbo said:

I don't think reducing the main jet is a good idea. Removing the snorkel, shimming the needle, and adjusting the mixture screw is proven and works well. It's all about the A/F ratio. You do NOT want to get too lean.
That's what I did. Didn't adjust the main jet at all.
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