Question about mud and power

[Stealth13]

I was riding my bike in a lot of swampy areas and it seemed to lose a lot of power as I rode it more. I then raced my buddies 250 and it felt slow and topped out at 130 and wouldn't go anymore... Does mud/dirt get into certain spots and do this?

Because before I could rip it up to 150 and a lot quicker.

[Pooley]

Could be your air-filter getting dirty restricting airflow, excessive weight of the mud, extra drag on your drivetrain, maybe even the breather hoses getting slightly plugged. Definitely clean around your front sprocket, chain guide, and anywhere else you may have rotating parts that could get gunk in them.

[Stealth13]

Ya I washed it and it was back to normal. Kinda sucked how a exc250 was only like 20 meters behind by 130...