20 50 mineral-based break in engine oil?

[RGS1000RGS]

So ... am I to believe the 'solid contaminants' drop harmlessly into the sump, never to find their way into the body of oil in the motor or the lubrication system again? So the oil doesn't discolour with use, all the bad stuff just drops like stones into a pond ... into the sump (where the oil pickup vent to the pump sits!) never to cause grief again? Apologies if I sound a tad cynical ... I'm sure it's perfectly good oil - I just have trouble with the spiel.

Cynicism is good and questions should be asked.

A bit of asking what 'Low dispersant Oil' is, and Mr Search Engine says that "an engine lubricant that contains minimal or no chemical additives designed to suspend soot, dirt, and combustion byproducts in the fluid. Unlike modern high-detergent/dispersant oils that keep particles floating so they can travel to the oil filter, low-dispersant oils allow heavy contaminants and sludge to naturally drop out of suspension and settle at the bottom of the oil pan. Older car, motorcycle, and tractor engines (typically pre-1970s) built with looser tolerances and without full-flow paper oil filters often require low-dispersant oils. Using a high-dispersant modern oil in an old, dirty engine can strip away legacy sludge all at once and severely clog narrow oil galleries."

Given that being independent, and Morris being a well established manufacturer and supplier of oils to the various motor trades in the UK, I'd give their 'spiel' some credence.

But it does raise another question that, if you are running an external cartridge filter, what is the process that you should follow? Flush, change the filter and then run a high dispersant oil? Or strip the engine, clean, flush, and then run a high dispersant oil?

 

[motoddrob]

I use Penrite HPR30 and change every 1500 kays. Comes out looking clean. On my GS1000 BM I change every 2000kays and change the filter every 2nd oil change.

 

[Andy J]

For what it is worth I use Morris oils semi synthetic in all my Zane 650/668 engines. I use Rock oil fully synthetic in the 750 race bikes as it was developed for use in that engine.
Golden Film is what goes into the 840 Breganze twin race bike and Morris V Twin is used in all my Breganze 350/500/Atlas engines.
Back in the day, when I first started racing the 500 twin, I used cheapo Shell mineral oil and changed it every 500 miles. Seemed to work okay.
Apart from a brief ‘experiment’ in 1985 with Amsoil in my Corsa proddie racer - it didn’t last long due to the cost and difficulty in sourcing it - I used a mineral oil in all my triples.