Follow up from another thread.
I have recently fitted new SRM,(AE) piston rings after rebore and honing.-+40 and 180 grit stones. Other forum members have suggested 30w running in oil to assist with piston ring bedding in process. I have come across two oils of choice Morris Golden Film 30w and Dynolite 20/50w. Has any one got experience of these oils ?
I spite of revving my bike's engine to over 4k revs going up hill and down, I am getting wisps of smoke from the sprocket area ( cam breather ?) at tick over when good and hot, after a 20 mile run. I am currently using Wilco 20/50 mineral oil of lowest spec.
I don't wish to run my bike any further for fear of glazing the bores. Would 20/50 running in oil be preferable to straight 30w ? Sparks plugs (N3) show no sign of oil fouling currently.
Bike is 71 reg A65L with SRM bearing conversion.
Thanks to Gavin and Allan for previous comments from another thread.
Regards from John

These engines weren't originally designed to be run using "multi-grade" oils.

Maybe the heat generated in an air-cooled engine is "thinning" the multi-grade oil too much?

The bedding in of rings occurs in less than the first 100 miles or so and the general recommendation is to use mineral oil together with initial hard riding up hills etc. Sounds like you are doing everything right and I'm not sure there is much to be gained from swapping oil at this stage. One reason for rings not bedding in is when an owner has left their newly bored & honed engine idling in the garage whilst they admire their handywork before a hard run in.

If the bike was burning oil due to bad rings I would be checking the exhaust for blue smoke on acceleration and oil deposits in the exhaust.

Don't know why you would be getting smoke from the breather area but maybe the oil pump scavenge isn't working as well as it could?

30 W is too light. 40 W would be more like it.
I use morris Golden film 20 - 50 for regular running.
I dump the cheap post rebuild oil after less than 100 miles. Thats when the worst of the process takes place, last time it was cheap Lidls 20-50. Thereafter , change at 250 , 500 , 1,000, by then it should be fairly run in. keep the revs over three K during this period, use the gearbox. On stock gearing the bike will keep up with traffic while running in, i like a mix of roads for this and avoid long dual carriageway runs.
Change primary case oil at the same intervals if the clutch is fresh, otherwise every 1,000 miles.
my running in regime goes like this.
Before starting the motor after a rebuild, the chassis is made roadworthy. after initial start , shut down straight away, timing checked on strobe , no extended idling. Put my riding gear on, after about 6 miles I attack a steep hill in 2nd and make the motor pull hard, after that back to normal running in, no extreme revs, 5K limit. There is a limited window for this, otherwise the bores will get glazed and the ring contact will not be ideal for a lot more miles..
Works for me.

The smoke may be steam from combustion blowby past the rings condensing as it cools in this humid weather, if its not blowing blue smoke out the exhaust then I would change the oil and carry on running in.

Thank you for your comments. As previously stated I do not want to glaze the honed bores by using the incorrect oil or technique.
In response to some of the points made. The bike has a SRM sump plate with the scavenger pipe correctly positioned away from the sump plate magnet and has a healthy oil return – although it does wet sump – but not badly. It has a Norton type oil filter in the return line.
I have had the boss ( wife) follow me to check for any exhaust smoke ( of any colour ) - believe you me she can spot what I am up to from 100 yards away under other circumstances !
When I had primed the lubrication system, I started up and idled the bike at 2k revs and above - blipping to warm up and them straight out up the road with 3 minutes. I revved the motor to 3.5k for 3 miles, stopped , let it cool and them carried on this time going to 4k revs ( and a bit above ) going up nearest hilly/bendy road. Then back home shutting the throttle down on inclines - again from 4k revs .Total mileage is approx 25 miles. The engine oil level has not significantly dropped within this small mileage.
I will put some running oil in (40w) if I can find it Gavin. I will also have a look around the final drive sprocket area for the source of the smoke - should it be from the breather or accumulated chain lube ? The cam end breather is difficult to see.
Web articles I have had a look at - Mahle, Wiseco , John Healy ( Britbike Forum) and Engine Builder, don’t give a firm indication of the mileage at which iron piston rings bed in. I see that bore glazing can occur within a short distance/time, hence me stopping running in at the point.
Thank you again.
Regards from John.

If I've only done the rings I use the cheapest, non-detergent 40W I can find. The rings seat in very little mileage, usually within a mile.
Ride back home, put in good oil, done deal.
NOT recommended for a total rebuild.

Shouldn't the term be "RUNNING-IN oil?"