skylane42

My Feedback: (53)

I have a 20 year old OS SF 61 2 stroke that I got from a guy who said it has been sitting for that long. He did run the motor a few times in a Aeromaster. The motor is pretty much locked up. I started tearing it down. One of the problems I am having is I can not get the con rod out to pull the piston. I have the sleeve out. The wrist pin is frozen so I can not slide the conrod out far enough to clear the crank. Is there a proper position the conrod needs to be in for disassembly? I have tried at the top and what looks like a recess at about 4 o`clock in the crank. Right now I have the piston wrist pin and piston soaking in WD-40.

Also I tried to slide the sleeve back in and just binds. Does the case need to be heated to re-install the sleeve?

Bax

My Feedback: (11)

First off, you'll likely need to heat the piston/wristpin/rod assembly to soften any cooked-on fuel residue. You probably have a lot of fuel residue cooked onto the wristpin so that the conrod won't slide to one side, Once you can get the rod all the way to one side of the piston, then you can remove the rod from the crankpin. Even so, you may need to pry the lower rod end off of the crankpin. Use the head of a large carriage bolt as your lever. Works very well.

The ring groove in the piston has a pin that is used to prevent the ring from moving. The ring gap goes there. If the ring isn't lined up so that the ring gap is at the pin in the ring groove, the cylinder liner won't slide down. If you look at the top of the piston, you should see something that looks like a dot. It will be located towards the rear of the engine on the side away from the exhaust port...on about a 45-degree angle from the center of the piston with reference to the engine's fore-and-aft centerline.

skylane42

My Feedback: (53)

Well, I broke the bottom of the piston trying to get it to rock.. it is a ABC motor. I think with all the rust on the bearing etc I will just sell off what good parts are left. Thanks for the advise.