replacing piston and rod???

You must first remove the head and cylinder liner to allow enough lateral movement of the piston & rod assembly to slip the rod off the crank pin.

i have gotten as far as having the sleve out already. the rod does not seem to want to slide off the crank pin. i even grabbed it with some pliers and pulled on it but still no luck.... arghhhh!!!

Turn the crank to a position that allows the con rod to slide off. There ahould be enough lateral movement for the con rod to slide off without having to resort to pliers.
Declan
Regards
Declan Barry

I'm not completly certain, but I recall removing the sleeve first. Then you would have enough room to move the con-rod back enough to clear the crankpin.

Should just slide off. You might have to rotate the crankshaft around a bit to get to the sweet spot. I just replaced the bearings in my GMS .32 and I recall there was a certain crank position where the con rod slid right off.

Usually you have to turn the crank until the piston is low enough to fit into the rear transfer port slot. That should give just enough room for the rod to slide off.
-- Paul McIntosh

I have run into a case where the varnish (burned castor oil?) coated the wrist pin, interfering with lateral movement. The crock pot full of antifreeze fixed that in 24 hours, and cleaned up everything else.
Pliers is not the way to go.
-- Mike Norton

First remove the back plate from the crankcase , then remove the head. Usually there is a notch in the top of the liner....if not mark it so you can get it back in the same position. At this point push the piston to bottom , then pull the liner from the crankcase. Sometimes it may be a little hard to remove. If so , I normally slide the edge of a utilty knife blade under the edge of the liner. Don't pry it , just slide the blade underneath the liner and run it around as though you are trying to cut the liner off at the top of the crankcase. Usually just the thickness of the blade will break it loose. In some rare cases I had to heat the crankcase near the top . Since the aluminum case expands at a faster rate than the liner , this will usually loosen it to a point where it will practically fall out. A monokote heat gun is usually plenty of heat for this job. Be especially careful with the top of the liner as this is where the seal is made between the head and liner. With the rod pin at the bottom of the case this should allow you to pull the rod off the crank pin. Make a mark on the rod so you can identify the back side. Needle nose pliers are okay to pull the rod off , expecially since you're going to replace it anyway. Just be careful and don't bang around in there. Don't try to pull the rod off by grasping where it fits on the crank pin...but go higher as you actually need to slide the rod rearward on the wrist pin . Sometimes pulling on it at the crank will cause it to bind. Then slide the piston and rod assembly out of the case.
Hope this helps.
Ken Day

refer to step by step photo instructions at = How to Rebuild your Nitro Engine
see also regards Alan T Alan's Hobby Model & RC Web Links