Oh, one thing I just recalled before the work. Since I already replaced the upper
tube seals, so it is not likely to be the tube seals leakage. If we disregard the
high compression assumption , it is quite likely from the lower O seals. To
comfirm this, I cleaned the spark plug tubes carefully a few days before the work,
then after a couple of days I pulled out the spark plug wire (very slowly w/o
touching the sidewall) and I saw oil trace from the lower connection area and
the upper connection area was spotless. of course, if the oil in the tube is too
much, it is hard to tell. Anyway, hope it can help some beginners who has the
same problem cauz it is not an easy job for us to remove the rocker arm
assembly. It is better to be sure before you turn the wrenches.

 

Glad that we could hekp and happy that you got the job done ..