Cyl Head and Elevation
I think elevation has something to do with performance of the smartcarb and porting of cylinder heads.
Most of you guys are riding at 2000 ft or lower elevations = higher air pressure.
For most of you in the mountains above 4000 ft, well the air pressure is going to be low anywhere in north america.
I have a 2015 KTM XC-W and its been challenging to get running sharply as the CR500 I had.
2015 300XC-W storey:
The stock bike had a 165 main jet, I now have a 157 main and it still too rich.
The stock bike had a N8RG needle, the third I am trying is the leanest NECJ.
The stock bike had a 38 pilot jet, i have a 35 pilot at 3.5 turns out on Air Screw.
The stock bike had a 7.0 slide, I have an 8.0 slide in it now.
This bike is still not crisp enough but getting better.
What these huge jetting adjustments on the new 300 XC-W tell me is that with Roostius Maximus's porting on my CR500 I had may have been too much volume (low compression) for the 6000 ft mountains with dry air I ride in. Roosty's at 700 ft elevation. Roosty's smartcarbs would also start in a couple kicks.
Now the CR500 ran pretty damn good with a 38mm PWK but I don't think it had enough compression with Roosty's head mods.
Now with a 38mm Smartcarb on it, the CR500 never started once in less than 40 kicks
. Would more cylinder head compression have helped? Who knows.
All I know is KTM SX heads are higher compression for higher elevations.
Seems to be the consistent storey I am finding over 6000 ft in dry air conditions. That might possibly apply to most of the riders Chris is familar with having SC not working.
My thoughts,
Patch