the dynamite engine your speaking of is a simple engine to work on strip it down and remove any casting flash you see in the block or any machining flaws you find, next take your crank and look in the intake port and clean it up in side the port you will notice the wall sides are not true due to how it was machined round it out with no edges dont make it bigger and dont mess with the slot your just fixing the machine work inside when its done polish it up put the sleave back in it aligned up right and look in the exhaust opening if you see the sleave is over hanging the bolck mark the sleave it and make it match the opening in the block but if you do this taper the outside of the sleave to your mark DONT get into the chrome so the hole is the same size on the inside of the sleave your just making it flow better check often as you cant put anything back once its gone its gone!!!!! SORRY I missed a step but not really, still on the exhaust on the block end of things remove any casting flash you see in the exhaust exit also it has a curved side clean this up also makesure your gasket matches and your header to.....I think that just about covers it...

Remember this is not port tuning your engine!!!! But it will make things flow better resulting in a little more power..Its not hard to do but be carefull you can still mess it up..

Oh and the link provided with the TX15 was just to give him something to look at as there is not much info on the net about this subject and that one is great for knoledge because it has pictures of every step and explanes things well And please list FREE links about working motors, if you know any that are willing to give info that is worth 10 cents.........And about these small engines they are all modified plane engines, boat and car both with an exception or two