Motorcycle Repair: my 1972 honda cb 350, honda cb 350, pb blaster

Question
i have a Honda CB 350 and the motor is freeze what can i do to unfreeze my bike.

thanks

Answer
Ken, if the pistons are stuck in the cylinder bores, it is due to rust and corrosion. In some cases, where the corrosion bond is recent, then you can try a penetrating oil like KROIL or PB Blaster or some people have good luck with diesel fuel in the cylinders. The problem is that it is more than rings stuck to the cylinders, the problem is that the corrosion has occurred between the rings and the pistons, so the rings can't expand properly. If you get the pistons to move, then the stuck rings will cause smoking and oil consumption.

There are other things that can seize the motors up, like broken camchains that result in bent valves and broken pistons.

The only way to do it right is to remove the engine from the frame and disassemble it to where you can determine what has caused the seizure. I have used steering wheel pullers as "pusher" tools to move pistons down the cylinders until they are clear of the sleeves.

This is all major work, and based on your question I am not sure that you are prepared to do major work with this engine, by yourself.

Shop around the local salvage yards, Craigslist listings and Ebay for a good replacement motor.

Bill Silver