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Erics350x
09-22-2006, 12:29 AM
just rebuilt my kids yfm225 moto4 . it ran great for the first 3 or 4 times till the other day it started smoking like crazy. i figured it broke a ring . pulled it apart to find the piston , rings and cylinder all look great. but there was about a 2oz puddle of oil on top the piston . i dont get it? could it be the o-ring around the dowel pin or the valve guides? i may have put some two-stoke gas in it but i put the same fuel in my X without any problems . i dont see that causing that much oil to get in the cylinder. any ideas?

MTS
09-22-2006, 01:56 AM
Didnt blow out the o-ring Around the dowl on the head where the oil is pumped though? Other than that i would say Valve seals....

Erics350x
09-22-2006, 08:27 AM
no, but it looks rough