How would you know if you had oil pump issues? bubbles in return oil??

Started by 1340evo, October 19, 2019, 10:27:42 AM

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1340evo

    So, today I changed my oil and filter and purged all the old oil out so its all new in there... Amsoil 20-50
    On the FXR you can basicaly run the bike with the filter off (as its on the return) until the new stuff comes through.

    but I was quite suprised at
    1/ the flow rate on tickover being quite low and
    2/ the amount of bubbles in the returning oil making it look quite milky in colour? (wish I'd taken a video TBH)

    othen than this, Ive had no reason to think the pump was faulty.. its run 2.5K since a full re-build (that said, the bolke who did the re-build, I've found a few other things wrong!)
    the oil pressure keeps off for 3 seconds following shutdown when cold, etc?....

    I have been reading about oil seals failing in the pump... but I've also been reading about new oil foaming?

    any thoughts... I guess at tickover the flows not going to be much... but there was a lot of bubbles in it for sure!!...


JW113

If the oil light is on, you have a problem. If the bottom end fills up with oil while it's running, you have a problem. If you look in the fill plug and can't see oil returning, you have a problem. If the tappets are clacking, you have a problem.

Other than that, good to go.

Between the spinning flywheels and the gears in the cam chest, the oil gets frothed up like crazy. Hence, frothed oil gets returned to the top of the oil tank where the bubbles (mostly) float to the top and disperse, and feed oil to the engine is taken from the bottom. I would not pay much attention to what the return oil looks like.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

1340evo

Thanks JW.. thats what I'm most thinking... you can't see it return to the tank in my year of FXR so never paid it much attention... but like I say, when its in front of your face, its close to white with the  bubbles in there. I'll give it a run tomorrow and get the level when warm.. I've just taken a bit out to allow for expansion ;)

JW113

You probably don't want to put a clear hose on the oil return line to the tank. You won't like what you see.

  :hyst:

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

1340evo


thumper 823

A dry-sump system has two pumps or two in one .
The pressure side does exactly that supply volume under pressure.
the scavage side is bigger than the pressure side so as to clean up the mess in the bottom of the crankcase.
It will suck oil, air and oil, whichever there is more of, and send it back to the tank.
To see air coming through is perfectly OK.
D Troop 3/5, - C/16 ,162AHC, Mekong delta.
Rising from the Ashes  UHIH

1340evo

yes. but it was something I'd not seen it like before... taken it for a run and it looks like its cleared a lot??   low amount to pick up and air like you say...

Burnout

The return pump is twice as big (or more) as the oil feed pump.

So ~half of the returned volume is air.
They don't call me Ironhead Rick just because I'm "hard headed"

1340evo