need help with nasty scratching sound

[Fordtrucker17]

ok well i just put new rings and a piston in my blaster took the carbruatr (sp) to votech took it apart cleaned all nice and stuff my dad said we didnt need to hone the cylinder becase there was nothing wrong with it ok so we put everything back togther and my uncle is like kick it over i kick it and it back fires really bad and it seems like it has a lot of comperssion at times and other times it makes a really bad scratching sound. the rings and piston are in right. we also got a oil injector blcok off my uncle thinks the piston is gettin to much gas and not enoughoil idk please help me i dont feal like puttin money back in this thing

[YZ400EX]

You should have honed the cylinder wether you thought it was needed or not..it needs to be at least honed every time you replace the piston and/or rings. It is needed for them to properly seat. I dont know if thi is the problem or not, but thought you should know..