Thanks for the feedback and suggestions. I have since added an inline oil check valve that Yamaha uses on their jet ski oil lines and it’s helping to avoid air bubbles. I agree the bubbles aren’t a big deal and more the fact that it’s noticeable using a clear line, but I prefer to see and keep an eye on if it ever runs dry for too long signaling a different issue. 

I see Im going against the grain here, but there is something magic about watching the oil pump up along a clear line and your bike is burbling away waiting to be thrashed in the nearest field. I can't remember if it was Ducati or Kawasaki that made a bevel geared driven single and you could add a clear port cover - usually just get clouded up with oil though! I mean everybody loved the 'skeleton' N64 but that's way off topic!!!!!!!!!!!!