so how do i do this
 

ok so have a ofna ultra lx comp and it was leaking fuel behind the flywheel so i ask wat was wrong with at a hobby store and they told about somethig about a seal that wore out or something idk
so im trying to take my engine apart but im stuck at taking out the piston need a little help on wat to do

If it's leaking behind the flywheel, your front bearing is most likely the problem

You'll have to find the dimensions of your bearing and get a new one.

here's a vid to disassemble the engine. Same concept between the engine in the vid and your .21 or .28 or whatever engine
http://www.youtube.com/watch?v=9v4ePOjjKNE

and then when you get to the bearings, there are various ways to getting it out. Bearing Puller tool, puttng the case on a heat source to expand the metal, etc...

good luck, but in your situation, i'd have a more experienced person help you out... or get a new engine. how old is it?

thanks for the vid

its the .28
its 4 years old but i barely have ran the thing at all it seems like
it is pretty much was a waste of money and i started it up again a few months ago and it ran fine for a while but then it started to leak and i been putting it off until now

I cant believe that video skipped the bearings! That's the toughest part! and Danny's biggest problem