goober1969

I have a 2007 YBR 125,,,20,000 km The bike bent the intake valve on cold start,,,,changed the valve guides 2 weeks later same problem,,bent intake valve,,,took the cyl off and checked the play on the crank and piston,,,they were ok. Found inscribed markes on the bottom of the cyl jug and inscribed marks on the crank shaft counter weights,,apears there was a problem at the factory,,,anyone herd of this problem,,,I would like to get advise before i open the bottom end?????????????????? Terry