Carb Jetting/Tuning For Dummies.

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wogtaz ryder

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A very nice guide that comes with the Purchase of a Pitster .

Its the most easy to understand guide i have seen for tuning a Carby , if you dont understand after this , your stupid.:cool:

Conveniently fit on 1 page . Print it out and take it to your bike!


Setup_jettingmadesimple.jpg



Here is some pretty graphs and things that will teach you more about tuning.
Smaller_PWK_highlow_speed_animation.gif

graph.jpg

Davids_Jetting.jpg
 
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bulldog93

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It wasn't working for me? Came up with a little white box with a red X in it. So I posted it again and now I can see it.
 

140er

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great guide is it for molkt 26mm carb. the ones they stick on stomps
 

wogtaz ryder

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It looks like they are using a molkt carby.

But its the same concept for most carbies.
 

wogtaz ryder

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Added some nice graphs and things to the first post .

Shows alot better how a carby works
 

March

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I have a new atomik with a 140 yx been ridden for about 2 hours, It is spluttering and coughing and backfiring occasionally, and sometimes sounds like something is happening in the carbi. When i give it some revs to get up a small hill it dies on me and sound really rough. I moved the air fuel screw to try and fix, I've read to screw between 1.5 and 2 turns out, is this 1.5 whole revolutions?? because I have done this and still it inst running right, and it seems to be getting very hot.
I am very new to this what should i do??
 

sean01

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ok, the 1.5 turns is just a guide to know that you have the pilot jet size near perfect.. and its 1.5 - 2 turns from screwing the fuel screw all the way in and winding it out..
and the fuel screw will only effect it from idle - 1/4 of throttle..

so pilot and fuel screw for idle to 1/4 throttle
slide needle for 1/4 to 3/4 throttle
and main jet 3/4 to full throttle

running hot is a good indication that it is running lean, but before i touched the carby i would be checking the valve clearance.... .003 tho on the inlet .004 thou on the exhaust..

if you adjust the valves and still find there is a stumble in the rev range then the slide needle will probly need raising/lowering by 1 notch at a time.. if the problem gets worse as you raise/lower it then start going the other way..

IE: moving the clip lower on the needle raises the needle and moving the clip higher lowers it..
lower for rich and higher for lean...

if you get to a stage where you have the carby apart.. let us know what jets are installed..

another good thing to try is doing plug chops.. as seen in the first image above...
 
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