I haven't heard of any other cases of valve recession for the ZS177MM/NC250 engine. I also find it difficult to understand how adjusting the intake valve too
loose would cause valve recession.
CO2,
Have you been riding in dusty conditions? Did you oil your air filter? Have you examined your carburetor boots for possible damage? I ask these questions because I wonder if dust is entering the cylinder head with the fuel/air mixture.
__________________
Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894