Suzuki 2 Strokes

How to assemble piston on crank ?

Finding it difficult to keep the crank bearing and piton hole aligned while trying to insert wrist pin.
Specially the wrist pin is not loose enough to just align the crank bearing with hole in piston and slide wrist pin in,
as wrist pin is too tight going into piston.

What are my options?

I am considering to reduce tightness of wrist pin, by increasing diameter of hole in piston somehow.
Would it be a bad idea? If yes, then what are my options?

thanks.

DO NOT attempt to enlarge the hole in the piston...yes they are tight, they're supposed to be. Any slack in this joint will break the piston pretty quickly once the engine is running, apart from making an awful noise.
Ensure the components are all perfectly clean and lubricated. Tap the pin into the piston (left piston/left side....right piston/right side). A toffee hammer should be sufficient for this...tap it in until it just appears in the rod opening. I use some pieces of wood to support the rod against the cylinder studs...chock it well to reduce any sideways forces exerted. Once your little end bearing is located, line up your piston, and continue tapping the pin through. Always stuff some rag into the crank case openings to stop anything from falling in...
This is how I have done the job dozens of times without any issues....there may be some kind of press available, other members may know, but this will work.
PS....make sure you are not trying to drive the pin over a circlip. You can put the innermost clips in before driving home the pin.

A piston pin puller will make the job a lot easier.

Use the 'heat spanner'. Keep the gudgeon in the freezer for an hour or two, and warm the piston with heat gun or rag soaked in hot water then assemble.

Press it in using some m6 studding nuts, and a selection of washers and 3/8 drive sockets.