Hi all
I think the mod was made by the well known Belgium Morini dealer Enzo on a 350 Kangaroo. He might also have fitted the L5 camshaft that's in the engine, so i guess his intensions were to race the Kanguro off road with this configuration. When i bought the Kanguro it had been standing outside for a while and the pistons were stuck because water had entered the heads (no filter can help against such behavior i guess) The bike was already taken apart so no pictures of the finished result unfortunately. I will use the base of the engine to built it into my 350 Valentini replica. It would be much more Valentini like with the hot camshaft then using the stock M camshaft (of the K2 engine that's in now).
You are right Ross, the side cover of the 350 is the same as the 500.
As for the 'plumbing job', i agree that changing the oil on a regular base helps, so start with that
To early on a Sunday's for me to reply on the plumbing bit, but where i do have an opinion about is looking on the overall external oil filter mod and looking at a lot of especially German Morini Riders who use it, and from my part of the story having experience with broken engines:
if you look at other (Italian) bikes of that era, the Morini is a bit under filtered (considering the fact that the main plain bearing obviously need clean oil to function well as do other sorts of bearings), and also the way the drain plug has been designed, keeping the engine clean inside is not such an easy job as with Aermacchi's, Benelli's and especially Moto Guzzi's of that era for example. I think the extra oil filters are really worth the plumbing but, although they look a bit awkward.
I would say, if you are into plumbing and you understand the way how these engines work (shut off the original oil flow, to force the oil into the external filter) then you could improve reliability a little. Of course the cooling advantage is not an issue with these little v-twins.
Maybe it will make such a mod of my own when rebuilding my 501 Camel engine, which broke down this summer due to lack of oil in the plain bearing. The engine had been rebuilt before (although i did not do it myself) and i did changed the Castrol oil on a regular base