[Shockwave78]

I rebuilt the bottom end of my 78 400 during the summer of 2023, new rings and bearings, honed cylinders, cleaned the valves, and replaced the valve stem o-rings plus a few other odds and ends. At the time I noticed what I believe to be excessive clearance between the valves and valve guides, I was able to slightly rock the valves side to side in the guides while they were off the seat. I wanted to install new guides and have the heads milled for wiper seals, but time and money didn't allow it. After the rebuild, it burns some oil but only smokes briefly after startup when it is warm, maybe for a second. I suspect it is due to oil leaking down the valve guides past the o-rings, before the rebuild I figured the mountains of carbon I removed from the back side of the valves kept oil from getting into the cylinders.

Does this sound like what can be causing the brief smoking on warm startup? Also, is there anything I can do to help mitigate the oil in the cylinders for the time being like a different plug heat range or changing the carb mixture? The head work is on my list, but I am in college so I will have to deal with it for now.