O.K the problem I had is the following:

As you know the lower end is lubricated by means of blow-by gas through piston ring gap. To get oil in the camshaft, oil muss pass through rear bearing, and since the rear bearing is sealed and there is no holes or something that allows the oil to get there...well, my camshaft was just dry. When I bought the engine, I put some oil there, and did it a couple of times, but the oil there is always expelled. After one flight some day, I felt that the engine was so rough turning by hand, that I thought that the bearings were damaged...then I took the cam cover off and found metal powder there.... took the camshaft and I found that it was bronze from the intern bushing, the cam seized the bushing there, and everything was dry there. So I cleaned up everything and put it together again, but I took the rubber seal of the rear bearing.
Started the engine, and the engine was a nice sweet engine, better than before, better idling etc... I flew the plane...and found the cowling with a big oil mess, now most of the oil was expelled through the front bearing (shielded but not sealed).

So my solution so far was making a pinhole on the rubber seal of the rear bearing, I put it back together and now everything is fine, it spits a very small amount of oil on the front bearing, but it is ok, not like before, but it tells me that everything gets the oil there.

I guess a better solution could be a shielded rear bearing and a sealed front bearing....but I didn't do that at the moment...still my solution worked for me.

The other thing was the burr in the intake pipe, just at the elbow, it was like a ring obstructing the pipe...I grinded it and the engine performed better.

My engine was funny also because it came with a muffler which had one nipple and at the opposite side had a threaded hole for another nipple... I just put another nipple on it and a piece of fuel tubing.... Once I wonder if I put the vent line to the muffler... and it worked ok...and the mess came only from the muffler.

I wrote to thunder tiger (taiwan) ....and the man didn't know about the muffler with two nipple holes...and told me that the intake pipe burr was corrected...so I hope you get a good one...
About the lubrication problems...the guy just said.... "the rear bearing muss be replaced since the seal was removed" ...and contact Thunder Tiger Europe for further problems... then I wrote again...ahh you don't understand the problem bla bla bla....but again I forwarded the email to thunder tiger europe....and guess what... NO ANSWER, from thunder tiger in Taiwan nor from Thunder Tiger Europe...

That's my story! I've already made a post about that if you search a little here on the forums

Hope this helps,

Jorge