I have the engine out of my Z900A4 whilst I am doing the restoration on the bike. Top end is off for guides, seals etc and as a result the barrels, head and cam cover have all been vapor blasted. Look a bit too dull and mat, but much cleaner than before.
However, the bottom end is fine and I am not going to split the cases just to have them cleaned. The A4's do not have painted cases, just natural alloy finish and whilst I have been over them with a small wire brush in a Dremel the cases still look very 'dirty' when compared to the top end as the finish is like a fine orange peel and as a result the dirt and grime trapped in the pockets does not get removed.
Any suggestions of how the clean the cases on the bench? Are there any chemical cleaners that can be used locally that can do the job or are there any solutions or processes that any member has used successfully?