Hi guys.
I've an interesting issue which I need help diagnosing. While I am reasonably mechanically-minded, I'm more than aware that a little knowledge is a dangerous thing. So before I commit it back to the garage or get the tools out, I'd like to gather some educated guesses on what's happening.
A little history first.
I went BPU around 5 years ago. Last year, it showed some signs of valve stem seal wear, smoking on startup, as well as smoking a little on boost.
A few months down the line and the oil pump needed replacement as it began to cause other seals to pop, like the front and rear main seals. We took the opportunity to rebuild the engine, balancing the rotating assembly while everything was out. To my knowledge, all seals were replaced and it had gone through a 'refresh' programme before being put back in. For good measure, I had the stock twins hybridised at a reputable company. It was December when the rebuild was finally finished.
This month, it has been consistently smoking from the exhaust after around 10 minutes of gentle driving i.e. just as oil temps reach optimum. It's white-ish smoke, which lasts all of 10 to 20 seconds and then disappears for the rest of the drive. Sometimes, if it cools down enough for a few hours, the smoke will reappear under the same conditions.
What could potentially be wrong? The fact that there's burning means there must be oil must be getting through to the cylinders, but from where? What steps would you take in a process of elimination?
Any thoughts would be greatly appreciated.