Bogs when throttles punched or full throttle after 50km/h

Hello im fairly new to this forum and i have a yamaha bruin 350 2008 i snorkeled it not long ago and when i go to punch the throttle after 30km/h it bogs then picks up if i hammer it from dead stop itl go till 50kmh the start to bog and wont go faster before it could do 70kmh it sucks because it almost stalls when i hammer it over some mud and im doing a 70km trip soon
It has one 1.5inch snorkel should i add a second one?