dlorj

My Feedback: (1)

My 120 twin is gummed up and will probably need new bearings. I am to the point of taking out the camshaft, but do not want to damage the engine. Is it possible to disassemble it any
further without special tools, or should I send it in? I would really rather do it myself than have to send it in.

Bax

My Feedback: (11)

No special tools are needed to disassemble most model engines, including O.S. engines. Just metric hex keys (2.0, 2.5, and 3.0 mm). Some engines need a cross-point screwdriver. A #1 Phillips needs the tip ground down because Asian cross-point screws don't need a screwdriver as pointy as the Phillips.

dlorj

My Feedback: (1)

The questions I should have asked are: how do I get the camshaft out? Does it require taking off the cylinders and disconnecting the rods and taking the rods and pistons out?
Do the cam followers (lifters) slide out from inside the case? If the case is heated, will the camshaft slide out? I'm guessing the crankshaft will slide out the same way - heat?
Thanks for your help.

Bax

My Feedback: (11)

You only need to heat the crankcase to remove the bearings. To remove the camshaft, you have to remove the cylinder head, pushrods, and pushrod tubes. The cam followers will then lift up, out the top of the holes. The cam will then just slide out.

Once the piston/rod/cylinder assemblie's been removed, the crankshaft will slide out the back of the engine. Sometimes rappng the end of the propshaft on a piece of wood, or tapping it with a plastic hammer is needed to break it free, but it should slide in and out with little effort. We only use finger pressure to replace it.

Please check with RC Modeler magazine. They published a book on O.S. Max 4-stroke engine disassembly and assembly. We don't know if it's still in print.

dlorj

My Feedback: (1)

Thanks for your help. It's clean and back together, and all is well!