125/150/250/300 KTM/HUS/GG jetting thread

Installed a tsp high comp head on my 2020 150sx a few days ago. Noticed more pull in 3rd gear but does sign off a little sooner. Good for the type of riding I do however. Overall now have a full pro circuit system and the head. I have always been curious however, howecome the jetting in this thread works out to be such a huge main jet for the 150sx. The manual recomends stuff like a 460 and 470, and when I ran that before I had no issue on the top end. I am however using a 520 now in 24C weather and its good, just wondering why going so big hardly made a difference if any. 

Second question is I am having a bit of a bog when I am lugging the motor by being in a high gear and try and whack the throttle full out of a corner for tighter single track stuff. Not sure if this is just a 2 stroke thing as this is my first 2 stroke, or something that can be fixed with jetting. Seems a little flat towards the bottom imo

I think the jetting here is mainly for Mx, more wide open type riding….for single track, likely would not need such a rich main, I”m using a 480-490 main for Mx but I”m not the rev ranger I used to be..you may have to experiment with your powervalve adjuster and gearing to coincide with jetting for woods/ single track riding…IMO….I brought my 150 yesterday and never unloaded it😂…track was deep and needed my 300SX …

Yea i may try a leaner main. The 520 might be too rich for what I do. These settings for the mid range have been great though. Any leaner and I fear it would bog

I am running a 510 main on my 150 for MX.. and I rev the crap out of it.   It loses top end and overrev with a 520.  Will not rev out clean and pull hard on top.   I only go 520 on it in colder temps.