Jim Stewart wrote:

I'm rebuilding the top end of a 1964 Honda
S90 motorcycle engine. The work is nearly
done, but I'm concerned about the 40 years
of accumulated gunk in the crankcase. I
really *don't* want to split the case, but
I would like to flush it out somehow.

I'm thinking that before I put the cylinder
and head back on, I could fill the case with
stoddard solvent, kick it over a few times,
drain it and repeat. Before starting the
engine, I'll fill it with fresh oil, which
I'll replace after 15 minutes or so of running.

Would this be a good idea or will I mess
something up?

Is that one of those old pushrod Hondas ?

ff