2012 300XC/SX

Wow

I installed a SX CDI and a SX cylinder head on my 2012 300 XC a few weeks ago and what a difference. The power curve is more abrupt and snappy.  The torque is amazing.  I thought I would share my jetting experience to get a nice crisp powerhouse of a 300.

It took me a few minutes to realize that the jetting was off from the XC settings.  After a morning ride, of just messing with the air screw,  I changed from a 38 pilot to a 40 pilot and that seemed to help.  I then called James Dean, I have his needle installed, to see what he thought of my settings.  these are the settings he recommended. I ride at 3000-5000ft 

40 pj

168 mj

blue needle at 3rd clip

air screw at 1-2

 

I never had any spooge before and now it just seems to slightly moist around the silencer opening.

 

This bike will pull from idle in 2nd gear like never before and revs like a beast

 

thanks JD 

thx for the info!

Just rode my buddies 300sx last weekend. I couldn't believe the difference between it and my 300w! Shocking really. I wasn't sure if it was gearing, ignition or what, but it was noticeable. Fun for a while but I will keep my W for long mountain rides.

Did the top end pull for longer? I was thinking of putting a 125sx cdi on my 200 exc

It actually seemed to flatten out on top so I raised the needle ( more fuel) and now it pulls longer.

Update

I rode a full day at 5000 ft and had some spooge by lunch. Then by afternoon it was a trickle down the silencer.

I changed to a 165 MJ and air screw at 2. Put the red spring ( from yellow) in with adjuster in 1 full turn from flush. Seemed to cure the spooge and the power is like Great Odens Ravin

I recently made the same mods to my 13 300XC. SXS head and CDI, JD jet kit, FMF fatty with power core silencer, still running the yellow pv spring and swapped rear sprocket from a 50 to a 48. The bike is an animal! The motor pulls to the moon all across the board. Definitely one of the most effective 2 stroke bikes I've ever owned.

Enjoy your beast!!

I recently made the same mods to my 13 300XC. SXS head and CDI, JD jet kit, FMF fatty with power core silencer, still running the yellow pv spring and swapped rear sprocket from a 50 to a 48. The bike is an animal! The motor pulls to the moon all across the board. Definitely one of the most effective 2 stroke bikes I've ever owned.

Enjoy your beast!!

Yea buddy !

I want to try the 48 when I need a new rear sprocket

Yea buddy !

I want to try the 48 when I need a new rear sprocket

The 48 really helped in getting the newly found power to the ground effectively. With the stock 50 on the bike every time the bike got on the pipe the rear end was swapping out. The 48 basically eliminated that unless I want the rear end to come around.

I was a little worried how the taller gearing would effect the bottom end when I crawl through a technical section. Turned out it had very little if any negative effects. If anything I need to carry a little more momentum but that actually suites my riding style better.

Overall I couldn't be happier with the setup.

Sweet

Wow

I installed a SX CDI and a SX cylinder head on my 2012 300 XC a few weeks ago and what a difference. The power curve is more abrupt and snappy.  The torque is amazing.  I thought I would share my jetting experience to get a nice crisp powerhouse of a 300.

It took me a few minutes to realize that the jetting was off from the XC settings.  After a morning ride, of just messing with the air screw,  I changed from a 38 pilot to a 40 pilot and that seemed to help.  I then called James Dean, I have his needle installed, to see what he thought of my settings.  these are the settings he recommended. I ride at 3000-5000ft 

 

Great to hear just what I wanted it to be. :thumbsup:

 

I ordered same kit to my 300exc. Gonna install it in few days. I just build up the Powervalve on the cylinder.

Edited by KTMfinrider

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