Paint and oxidation removal

After the disassembly, cleaning the individual parts and removing the bearings, the next step was to remove the genuine silver paint on crankcase halves.  

This was done by applying the layer of chemical remover with the brush. Note that the engine serial number punched bears only the particular code of the bike (5Y7) on the japanese home market models.

Following issue was to remove an oxidation and dust on the limited accessible places like valve cover.

We wanted to avoid sand blasting in order to preserve the contact surfaces intact, so a variety of abrasive wheels, sand paper, thinner and slow manual work have been utilised.

Another problem to be solved is a missing edge of the upper rib of the cylinder.

The plan is to paint these parts with a primer and then with a black gloss coat suitable for high temperature. At the moment, it is clear, that another parts have to be replaced, eg. the valve guides and the valve rocker arms.

Engine disassembly and cleaning

Appart from esthetic constituent, the mechanical side of thing is equally important. Many customizers on the popular bike scene nowadays basically don't mess up with the bike's internal parts. They buy the most preserved bike possible and do mostly the visual stuff, using a broad scale of aftermarket parts and add-ons. Hm, I would be most cautious about starting customizing a classic bike, nevertheless I am far from denying the creative input which sometimes leads to wonderful unique rides. Anyway, the bike we got here is not just this case. The engine rebuild was considered as necessary earlier, due to the srx strong inclination to drink an obscene amount of oil:)

       

The first momentary inspection revealed no major issues; even the piston and the cylinder show no excessive damage. A thorough inspection will follow. The intention is to restore the engine from the scratch and to replace all the bearings and seals, but primarily the piston and the rings, the gudgeon pin and the circlips, valves and other parts which turn necessary to replace. Luckilly, the srx 400 shares very many parts with its bigger sister, the "600." However, some OEM parts must be ordered directly from Japan, because the srx 400 has never been oficially sold overseas and these parts are specific to this model. Some parts, like the head gasket, are allegedly already out of stock...