More Crankcase Breather issues on Model 50 - lost all oil !

Check for return at the oil tank. The return side of the oil pump has more capacity so one might think it's not pumping. If the pump was installed dry, it won't suck oil out of the sump. I usually get as much oil into the pump as I can on assembly and squirt some oil down the return line to assure the pump isn't sucking air. Try that then kick it over to confirm return.

Mike R

Before jumping to conclusions, Mike, just consider what's happened. Presumably, apart from wet-sumping (which is "normal") the oil system functioned OK before you fitted the NRV? If that's the case then it must be a result of your fettling rather than a faulty pump?

Prior to sending the pump to RGM it would be worth double checking your NRV installation, (even to the point of removing the NRV and seeing if the same fault occurs), checking connections for correct flow direction and carrying out the procedure set out b Mike R.

Best of luck with it all.

George

I'd check that you've put the valve in the right place in the plumbing and also the correct way round. I once plumbed my Commando oil tank breather incorrectly and the muck and fumes blown out of the bike was awful.

The symptoms would point to the valve being fitted in the return not the feed pipe so preventing oil returning.

I always check the oil return before setting out.

The brass bullet thing is in the oil feed to the crankshaft from the oil pump. The output of the oil pump is stationary and the crank is turning, the brass thing allows oil to flow from pump to crank.

The oil pump is a gear pump so won't suddenly stop working and is unlikely to be the problem. You either have a blockage on the oil pick up to the scavenge side of the pump or the pump isn't priming itself. If you have a sump full of oil the pump should prime itself, so a blockage is possible.

As you have been fiddling with the oil pipes by fitting the valve is there any chance you could have kinked the return pipe so that it is restricted? It seems odd that it was ok before you fitted the valve.

Have you removed the pump? If not, it might be worth removing it and checking that the oilway from the pump to the sump is clear.

Ian

I am not familiar with this valve - if it's purpose is to stop wet sumping then it should be in the supply line as Ian S said - the IN marking would be oil in from the tank so it sounds like you have it facing the correct way .The oil pump is a very simple gear type pump - the cog on the scavenge side is larger in depth than the feed side so it always pumps more oil out than in . Remove the pump and check to see that both cogs are being turned by the shaft . Check the drive gear on the shaft for the key - if this has sheared off the engine will not be turning the pump. Check the brass cover plate for wear - circular marks where the pump gears make contact. These can be lapped out on a glass plate to restore pressure. Also check the oil supply / return junction block for obstruction . As Mike R noted the pump needs to be primed by filling with oil before restarting.

The brass fitting you questioned is the oil jet that feeds oil in to an oil way in the end of the crankshaft. The oil pump should have nipple that inserts in an oilway in the inside of the timing cover.

This oilway feeds the brass jet which feeds oil into an oilway which is simply a blind hole bored through the center of the crankshaft . This hole is intersected by another bored radially through the timing side flywheel . The hole exits on the inside of the flywheel so that centrifugal force sprays the oil being pumped through it on the big end of the rod and crankpin.

All of what I have described is based upon my 1950 motor and I am presuming that the mechanics of yours are similar if not identical.

As said, these pumps are very robust and rarely fail completely. The fact that the crankcase is filling with oil shows that the pump is being turned by the crankshaft so I can't see any reason the return gears wouldn't be turning unless the key has sheared.

If the brass jet in the timing cover was missing then oil would slowly fill the timing cover, drain into the crankcase then (should) be returned by the pump as normal. You probably would still get some feed to the big end although obviously it would be reduced. Roller big ends don't actually need vast amounts of oil.....

As suggested I would try without the non-return valve fitted and see if that improves matters.

It's a well-known fact that gremlins hide in spring loaded valves. Once it's connected, they can escape and get up to their tricks anywhere in the lubrication system.

Hi Mike - does the oil feed for rocker shafts tee off the return line between crankcase and oil tank ? If so have you checked tee for blockage ?

not model 50 but when my es2 started burning oil like something from a bond movie. it was the bore knackered burning copius amounts of oil. it used half a tank in over 30 miles or so.the oil was coming from every hole available back pressure wise.

Previously mike_haworth wrote:

Previously Barry Carson wrote:

not model 50 but when my es2 started burning oil like something from a bond movie. it was the bore knackered burning copius amounts of oil. it used half a tank in over 30 miles or so.the oil was coming from every hole available back pressure wise.

Can't be knackered. Just been rebuilt with new rings.

.......................

no problem Mike just relaying what happened to mine . po said it had a rebore and new piston fitted. but after running it for a while the smoke got steadily worse. so i thought it must be the cyl head so i had that done . put it back together tried it still smoked . at the end of the day i found it to be a new piston had been fitted to an out of shape mirror like bore .

Barry