What a can it is!!
It doesn't matter (CR,RM, YZ, TM...). Just make sure it's oil and it's mixed in the fuel somehow, the owners manual is a good starting point. You're not going to find the 'Magic' oil that makes you win races, pick up women, win the lottery, land the dream job, look cooler to your peers and train your dog to add it to the fuel for you.
What you will find, however, is a million opinions on the subject.
Reccommend the thread be closed before more innocent people are sucked in to its magnetic allure...