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CR125 and 250 Jetting Thread,...

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We have been needing a jetting thread for both the 125 and 250 for a very long time, would be a great help for anyone who needs a baseline setting for there year, location, altitude etc. I know nearly everyone has had jetting issues with there CR's and most have even swapped out carbs to something different. I have had 3 CR's and all needed some jetting help. I would love to see this stay on topic and get sticky'd, I will start with my 05, its not dead on but pretty close, going up one size to a 37.5 pilot on the stock carb...

 

05 CR125

Wiseco Piston/stock bore

FMF Fatty w/FMF Shorty

Boysen intake and reeds

Moose Dual foam air filter

Stock Carb

32:1 Klotz Techniplate full synthetic/ air screw 2 turns out

35 pilot jet/37.5 on the way/currently a little lean on idle circuit

420 main jet/crisp and snappy, pulls hard all the way to WOT

Needle Clip 3 position down from top.

20 Feet above sealevel here in NC

Edited by Dirt Racer

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98 cr250

Wiseco stock bore

Vforce3 reeds

Stock carb

Fmf gnarly/TurbineCore2

58 Pilot

175 main

Stock needle 3rd clip

Sea level Oregon coast

1.5 turns out

32:1

This is what I like, its rich but I can run a NGK br8ev racing plug forever. Crispy and powerful without worrying about not getting enough oil.

Edited by guitarromantic

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I've done quite a lot of jetting with my 2005 CR144.  Currently running a yz pwk with TPS connected, VForce3 reeds, DEP 144 pipe, 100LL with Amsoil Dominator 32:1.    Near sea level in tropical climate.  My best setting do date is:

 

Needle: A685/294R, 4th clip.  (optional 2000 CR250 oem)

Pilot: 42

Main: 178

Air Screw: 2 turns

#6 Slide

 

I have very good settings with JD's Alternate Red, and N3CG/N3CF as well.  I get cleaner settings with #7 slide, but compromise "off idle hesitation" with aggressive throttle snap from idle, and low bog.  I get great results with a 5.5 slide (oem 99 CR250) but compromise 1/8 to 1/4 throttle response, no "off idle hesitation"/low bog.  With the A685, I get it all with no compromise, and I can adjust between trail or track riding with a simple airscrew adjustment.  Slightly spoogy.

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