classic motorcycle forum

Most of my machines use a hand pump, but the later ones use drip drip feed powered by spring pressure - just push the pump down against the spring pressure once in a while to keep the oil dripping at the required rate.

Have you considered using the mechanical pump to lift the oil up to an adjustable drip feed on the tank that feeds into the engine, with the excess pumped oil going back to the tank? This sort of thing was common on bikes in the mid 1920s.

Cheers

Leon

I will probably regret raising this, but here goes......

A standard B&L Mk II pump will deliver at maximum 500ml per hour driven at 1000rpm, according to messrs Best and Lloyd.

Whilst this is no big deal with most poppet valve engines of the period, which simply belch the surplus out, it is an issue for the Barr & Stroud engine.  One of the best documented and most widely repeated tales is that of Philip Brown and his 1,000cc B&S V twin engined Brough outfit, who seized the engine one day in Dorset whilst trying to cut back the oil to reduce the smoking.  What happens in the oil-tight B&S engine is that the excess oil builds up in the sump until the flywheels can get it, at which point commences a smoke screen of battleship proportions.  I've had this happen with Ever Onward, which is 500cc B&S powered.  The fix is to stop and drain the sump, which solves the problem, but isn't convenient, ever.  With the B&L set perilously close to off, it still over-oiled terribly.  It now runs a Pilgrim.  I don't have delivery rate data for a Pilgrim, but at around 4 drops per minute, it's fine.

Later Best & Lloyd pumps were designed to deliver only 200ml per hour, driven at 1,000rpm, 40% of the earlier pumps, and a tacit acknowledgement that 500cc per hour is too much.

My current project is 500cc B&S powered, and I have a lovely B&L Mk II pump, with tell-tale that I'd like to use, but I need to reduce the pumping rate to around 40%.

Has anybody gone down this path before?  What did they do?

thanks,
JFerg

Oil pumps then
You'd be best off on the AMC forum where they have extensive experience of these pumps and their many foibles, and how many arms and legs you'll have to sell to get recon ones

Chaps

It is wet sumping when laid up. To stop oil leeching into the chaincase when it is laid up, I remove the sump plug. So, it seems to be oil build up in the crankcase when running and thus leeching over to the chaincase.

Either breather is stuck open, pump scavenge problem,blocked foam filter, scavenge line blocked?

Hi
With a newly rebuilt engine the rings may not yet be bedded in ?
Recently I came across a similar issue with a G12, it turned out the bores were not true/square with the cylinder base
 
The owner has had the bike since the early sixties and had not had it rebored in his ownership ?
I believe the previous rebore was done using the head face as reference rather than the cylinder base

John