Yamaha 50hp Piston Installation

[DRywak]

Help! Please advise if a special tool is available or needed to install pistons from the crankshaft side on '84 Yamaha 50hp motor. If tool not available, please advise what procedure to follow.

[Forktail]

From the crankshaft side? Why?

[DRywak]

How do we compress the piston rings during the installation from the crankshaft side? Standard ring compressors will not work. Please advise.

[Forktail]

Usually the pistons are installed from the head side while attached to the connecting rod, and then bolted to the crank via the rod cap. It is unusual to install the pistons on the crank side. Again why?Regardless, you can use your fingers, or two small flat tipped screw drivers (brass tipped if possilbe). A ring compressor won't work becasue of the block design and because the crank is probably in the way.