AS Mike is leaning to, the larger displacement and CR is sucking harder on the exhausts. They may have sealed well with the stock pistons and no seals, and in the early stages of their life.
But now you're asking for more sealing from a guide that is worn and has no seals. The smoke will likely get a little better as you break in. But you may have a chronic smoker on your hands.
FYI: What is likely happening is that a little oil is invading the combustion chamber thru the exhaust guides and then being blown out the pipe. The exhaust valve is open for a moment I believe on the beginning of the intake stroke. Also, a little compression may be pressurizing your valve cover area, again thru the guides, and blowing some oil out the breathers. Which you'll see in your headlights at night. Not so much in the day.
On a performance bike this is tolerated. On a street bike, less so.
