Overweight motocross rider

Hi, I’m 6’2 and 260lbs/120kg and I want to buy a motocross bike. I’m indecisive as I’m on the heavy side if I should buy a ktm 125sx or a 250sx. Will either of them hold my weight or will I need to make adjustments or anything. I’m new to this community however I really want to purchase I bike however my weight is stopping me slightly however I’ve been on a diet for 2-3 months actively trying to loose weight