Oil Pump Question

I have done a full rebuild inc new crank and mains, my problem is no oil is showing on the stick after being run for a bit round the block, I am sure the pump may be gone?  1st thing is, I know its a 2 stage pump with 1 part pumping oil around the engine (I have oil at the 10mm bolt above the cam tensioner) and the other pumping it from the bottom outlet near the gear leaver back up to the head of the frame?....My question is which part (the inner part or the outer part lifts the oil back upto the frame?  Also how do I know if its had it by just looking at it.......?

Thanks in advance guys

How much oil did you put in?

Engine will take an easy 2 litres.

How much oil did you put in?

Engine will take an easy 2 litres.

I drained the oil last night and I got 2.4 lts out so there was loads in there!  Cant help but think its the pump but was asking before I take the clutch case side off?

Page 4-13 of the manual shows a diagram.  The pump in the oil pan moves the oil to the frame.  There's an oil check valve after the pump and before the filter.  I read where this can go bad and the frame won't hold oil when the bike is shut off.

Edited by Echo5413

The Lube path

Lube path.jpg

The check valve is a spring, steel ball and rubber coated valve seat in the right hand cover

right side cover check valve.JPG

Sometimes it can get old, and the rubber fail, or is damaged while removing it for cleaning, or gets stuck and does not fully seat

oil transfer tube.jpg


The check valve mates to the oil pump transfer port

right side engine.JPG

If the check valve is sticky, damaged, missing (home wrench mistake in his "rebuild" it took me all day to figure out once apon a time... until he brought me his "leftover" parts from after the "rebuild")

If the valve is not working, oil will still pump to the frame tank , but it will not stay there... and in the case of it being missing... or severally damaged.. you will have the majority of your oil pressure just pumping oil into the engine case, not flowing to the motor lube points.

To the OP....the oil pump is only available as an assembly, individual repair parts are not

If you decide to take the pump apart.... remember, the screws and other components are NOT AVAILABLE as service replacements.

If oil truly is not staying in the tank after shut down, i'd be looking at the check valve first.

Damn computer.  I just lost the whole long reply.  Here is the short version. The large inner rotor is the scavenge rotor to return oil to the frame.  Scavenge pump is alway a larger volume pump than the feed pump.

Damn computer.  I just lost the whole long reply.  Here is the short version. The large inner rotor is the scavenge rotor to return oil to the frame.  Scavenge pump is alway a larger volume pump than the feed pump.

Noble, I would really like to have read your long reply, looking at the service manual pics on both the oil pump and the flow diagram it has always bugged the heck out of me that it is not clear how we have both a scavenge pump (volume) and a pressure feed pump in what appears to be a single pump, is this done in some way by small orifice for pressure and large for scavenge ?


I am keen to fit an oil cooler in the oil return line and want to be sure that I in no way can affect the pressure feed to anything that needs it. The oil cooler is a kit for the drz400sm and it looks good as long as the line that leaves the crankcase for the frame can handle a one way valve and cooler high flow arrangement.


Cheers, Mike.

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