Oil...  Engine & Owner's best friend

There are 4 (I think) reasons for oil related engine problems: lack of oil, low oil pressure, choice of oil & old useless oil.

Looks like experts of all kinds disagree regarding mono, multi, synthetic & mineral, but ALL agree on one thing: put some kind of lubrication into the engine & change it often, maybe every 1000 miles or less. I believe this is by far the best advice, and the most important point in any oil-related discussion.

Other advices I've seen: regularly clean out the sludge from the bottom of the oil tank, clean the oilfilter & sumpfilter, check the function of the pressure release valve, & check the oilpump by at least looking at the oil-return to the tank. And when possible clean the cranksahft sludge trap.

Oil Flow Diagram

For the gearbox & primary I use whatever is at hand, most important  beeing that there IS oil in there. Original spec is sae 30 winter & 40 summer, same as the engine. So 20-w50 will do fine, if it leaks & you don't want to fix it for a while use SAE 40 or 50. But DO fix it some day! Some use red automatic transmission oil for the primary, it is said to lessen eventual clutch drag problems, or one may use standard gear oil.

Regarding oil pressure & wear: on my A10, the timing side main bush & big ends were in quite bad shape when I bought the bike -could move the crankshaft up & down + had "feelable" lateral play in both conrods. Still (never ever rev'ing it past approx 4500 rpm) it all lasted over 9000 km before I HAD to do an overhaul. Had fitted a very usefull SRM magnetic sumpfilter, effectively extracting metallic particles from the oil (monitoring the amount of grinded crankshaft circulating in the engine :o). Before the crankshaft overhaul I had been using mineral 30 to 50 mono, using thicker & thicker oil as the wear worsened (remember thick oil definitely improves oil-pressure in worn engines). After the engine rebuild I have been  using CETCO DB* 20-w50. Seems like many long time A10 owners have positive experience with this sort of oil, but just as many are very happy with monogrades, so...

* CETCO DB : Cheap-Enough-To-Change-Often, Dinosaur-Based.