Hi, I am about to put engine back together and was wondering, are the two alloy spacer washers needed between piston and con rod and if so, what do they do?

Cheers

They stop the bearing from moving out of position

Actually they do help hold the wrist pin bearing in place. But the real purpose for them is to centralize the connecting rod on the crank shaft. Some Bultaco cranks (not all) when pressed together allow the con rod to slide side to side. Sometimes they are able to slide a 1/16th of an inch or more. This sliding is prevented by using the aluminum thrust washers at the wrist pin. They are crucial so make sure they are installed!!!.

Steve

Thanks guys, spacers are fitted, will have saved a disaster happening!!

Myson