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British Bikes / Re: Best & Lloyd mechanical pumps
« Last post by john.k on Today at 01:10:18 PM »
When the Jawa Eso motors were used in road racing,return to the tank was by simply hooking up a pipe from crankcase ,and it worked quite well.........some here may remember the ESo s had a Czech made copy of the Pilgrim pump,that was much better made than the british one.
British Bikes / Re: Best & Lloyd mechanical pumps
« Last post by cardan on Today at 12:17:36 PM »

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.


British Bikes / Re: Best & Lloyd mechanical pumps
« Last post by john.k on Today at 09:51:34 AM »
I accept the smoking,but just because to crankcase oil level falls to where a steady level is maintained,an engine doesnt seize..............a sleeve valve is nothing special in this,if oil floods an ordinary dry sump motorbike ,clouds of smoke issue out,and the exhaust will fill with fact the motor cuts from an oiled plug long before it runs out of oil.....anyway ,the simple way to limit oil delivery is to limit the pump stroke..........which is precisely what Harley Davidson did with the pocket valve motors,where in the 26 on motors oil delivery was  modified by the throttle position.,as well as an adjuster screw. Pilgrim pumps. are similar,delivery is set by an adjuster,which limits plunger stroke.
British Bikes / Best & Lloyd mechanical pumps
« Last post by JFerg on Today at 08:39:35 AM »
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?

British Bikes / Re: 55 Matchless G9 primary chaincase
« Last post by john.k on Today at 02:15:30 AM »
I suggest you get a Norton single,or a twin.......then you will never complain about any other brand wet sumping.A Norton will often dump the entire contents of the oil tank overnight.....Back leakage thru the feed section of the oil pump.The common cure is a tap,but a much better one is a special demand valve fitted to a Yamaha outboard motor......unfortunately Ive forgotten the part no,but no doubt someone here will know it.......but last I heard Yamaha was back ordered on this valve due to unprecedented demand.........which they were at a loss to understand..........until they discovered the valves were for british bikes...........
British Bikes / Re: 55 Matchless G9 primary chaincase
« Last post by mini-me on June 23, 2019, 04:55:18 PM »
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 :o
British Bikes / Re: 55 Matchless G9 primary chaincase
« Last post by iansoady on June 23, 2019, 03:11:26 PM »
Do you see a decent return to the tank when it's running? I don't know the AMC twins but my G80 return was very sluggish.
British Bikes / Re: 55 Matchless G9 primary chaincase
« Last post by Oggers on June 23, 2019, 02:44:25 PM »

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?
British Bikes / Re: 55 Matchless G9 primary chaincase
« Last post by iansoady on June 23, 2019, 02:09:17 PM »
I can't quite see why bore wear should lead to oil in the primary chaincase unless the breather isn't working. Admittedly it will increase crankcase pressure but there won't be any more oil in there than normal.

How much oil comes out when you drain the crankcase, and have you tried doing it again after the bike has stood for a while to check it's not wet sumping?
British Bikes / Re: 55 Matchless G9 primary chaincase
« Last post by chaterlea25 on June 23, 2019, 01:54:51 PM »
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

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