Engine oil looking foamy and bubbly?

i have an rm 65 dirtbike and i rode it alot today. i wanted to go ride it some more and i looked in the engine oil window because i always check the motor oil before i ride it and the engine oil wasnt red like it usually is. it was foamy and bubbly. want does this mean? because i dont think its supposed to look like this. and i dont want to ride it untill i know whats going on.