Originally posted by Raw40
Hi sydewynder, yes I have checked the O rings on the jets etc all seem to be ok, the axial endfloat on the crank is 0.007", radial is 0 the bearing looks as if it's in a reasonable conditon apart from having a steel dust seal would it be better if I try and get a bearing with rubber seal?
You can use rubber sealed bearings but someone who's an engine guru here (Motorman) said he's seen some where the rubber seal piece heated up and seized onto the crankshaft causing the shaft to fail. Even so, many manufacturers are using rubber seals now so I would give it a try. I looks like you've determined the bearing is bad by the WD40 spray test. Did you do a similar test on the backplate and carb?
Btw way, how's the crankshaft? The area around the front bearing and the journal where the window is? Is the journal damaged. Some engines such as the Novarossi design the crankshaft to help prevent oil leakage and maybe air leak.