Kit's right, If you haven't checked your oil level, do so. Too much is no good.
What viscosity of oil are you running? How many miles on the bike? Filtration type and do you drive on any gravel roads???
Blowby is usually due to worn or improperly seated rings.
You might want to perform a compression test to see if things are normal. First test dry and then test wet (squirt oil in cylinders to coat rings). If there is a large difference and you aren't up to spec, the rings could be worn or the cylinders scored.
