I have just rebuilt my 160cc 2-stroke engine (70's series) - Cylinder rebored / new piston (+020) new crankpin and rollers / new gudgeon and needle bearing / new crankcase seals and bearings. My concern is that I've noticed that I have a variable float on the crankshaft and this worries me a bit! E,G: - With the piston at top dead centre, the crankshaft does NOT float in the crankcase - its nice and firm with no lateral movement. - BUT with the piston at bottom dead centre, the crankshaft floats within the crankcase by about 1.5-2 mm (i haven't put a dial indicator on it as yet to make a precise measurement but there is a distinct kock when I force the crankshaft back and forth in the crankcase. My queries to the forum are as follows: 1. Is a bit of crankshaft float permissible and if so, are there limits. 2. If crankshaft axial movement in the crankshaft is not permitted, what is the best way of removing it (Eg. Refacing the crankcase faces to obtain a tighter fit / installing shims behind the crankshaft bearings or spacer sleeve between the two drive end bearings? Any feed back would be much appreciated. I don't want to launch into recommissioning the engine after I've done all this work only to destroy the bottom end due to excessive crankshaft float.
