ORIGINAL: Gene Chernosky
As Dar says, do you have a warranty to work with? ...TT's have a 3 year warranty. It definitely sounds like a rear bearing failure of some sort...something that should easily be covered in the warranty.
FWIW, most 'sport' engines don't have bearings that are made to 'go' at higher RPM's for the most part of the running time on the engine. If you plan on using it that way you might want to consider high speed bearings or ceramics. Forget Boca Bearings...WAY to high!...try RC-Bearings.com.
They must really be using low quality bearings in these Chinese engines...
I have run SKF steel caged 608 bearings up to 100,000 rpm on several occasions (turbine), and I yet have to have a bearing cage fail on me! I do admit that I'm walking the line here, putting caged bearings in that thing... but so far so good.