rattling from blasters head?

[PhResTyL28]

i just finished a top end rebuild. i put new piston, rings, bearing, pin, gaskts, and clips on. i got a port and polish also. when i first start my blaster, and the engine is cold it sounds fine. but after it warms up for a minute or so, from about 1/4 throttle up i hear a rattling sound coming from the head area. i checked every nut and bolt there. came up with nothing, when i listen to it, it sound like the head. i know everything went together properly, clips were all the way in, pin was in right, new bearing was in there. i oiled everything good before it went together to. i cant find out why it is rattling. its runs 100%. some bogging on the low end but that could be cause of the humidity, it feels strong and pulls hard. just the rattle. does anybody have any idea what it could be?
those little rubber things between fins arent completely in at the head but its only a very small amount out. maybe i need to take th ehead off and make sure those are all the way in? i doubt thats it though.

it could be a loose engine mount, excessive crankshaft runout, excessive small, or big end rod bearing clearance, partial engine seizure, or a worn primary drive gear. if you can't figure out what the problem is, take it to a dealer

[PhResTyL28]

my cylinder is out of round.

i'll tell ya what sell them both & get a honda! or at least a 4 stroke! then u wont ever have these problems!

slowly repeating to myself... i will not flame, i will not flame, i will not flame

ok? good 4 u!

[OutlawEX]

I had a blaster for 3yrs and raced and i always replaced the bearing when i replaced the pistion and that seemed to take the rattling out..All blasters will do that ,i think its because they are air cooled,but dont be afraid to ride it, they all do it