125 Main Jet in an FCR carb?

I pulled out my buddies main jet today because his bike runs perfect everywhere, and saw it was a 125.... We live at 10,000ft above sea level and his bike runs great at 10,000ft, 6,000 ft, and 12,000ft! I have a 152 Main in my FCR carb and it runs fine but I still have a bit of deceleration popping. My needle is stock and 2nd slot from top. Stock Pilot. Should I go 147 or maybe 142? Im just confused cause 152 is what is recommended.

Thanks guys!

 

Oh and I have a 2008 KTM 450SXF

Deceleration poping is normal. If you go up on the pilot jet sometimes it pops less.

Main has nothing to do with closed throttle decel popping

That is pilot and fuel screw and/or air leaks do to poor maintenece of the hot start or exhaust.

 

If your buddy never opens the thottle Wide Open, then a 125 main would feel about the same as a 152..........

 

But I'd bet money it's not a 125.........it's probably a 155 poorly stamped.

 

Does the jet have the funny little Keihin 'K' stamped in it?

If it doesn't, then the jet size number is meaningless, as it could be a Mikuni or a Dyno brand jet......

Main has nothing to do with closed throttle decel popping

That is pilot and fuel screw and/or air leaks do to poor maintenece of the hot start or exhaust.

 

If your buddy never opens the thottle Wide Open, then a 125 main would feel about the same as a 152..........

 

But I'd bet money it's not a 125.........it's probably a 155 poorly stamped.

 

Does the jet have the funny little Keihin 'K' stamped in it?

If it doesn't, then the jet size number is meaningless, as it could be a Mikuni or a Dyno brand jet......

Yeah it says AB125 on it. Of coarse its the pilot, cause the throttle is closed. I dont know why that never hit me..... Thanks KRANNIE

I believe that  jet is a PWK two stoke carb main jet

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