Wet sumping=messy floor

Started up the 850 today after sitting for 2+ months (I was out of the country). Took 5 kicks to get it started instead of the usual 1 if it's been run within a few days but it fired right up and sounded good. But then I noticed oil flowing/puddling on the floor behind the rear wheel! WHAT THE...???

Oh yeah - Some time back I had rerouted the breather hose out the back of the bike, exiting under the fastback tailpice at the rear fender (not visible from outside). Enough oil had wetsumped that it was pumping out the vent hose. I'm guessing 2-3 ounces on the garage floor before it cleared. Looked pretty weird to see oil dripping from a rear fender onto the ground.

It reminded me that back when I disconnected the hose from the airbox and extended it to the rear of the bike I THOUGHT about setting up a small catch can but figured, "Ah heck, no need for that, I just resurfaced the oil pump so it doesn't hardly wetsump!" Well, I was sort of right. It doesn't wetsump enough do that if left for up to a month but it DOES if left for 2+ months. So I guess I need to rig that catch can.

Oh well, in the old days all that oil would have been soaked the bottom of the airfilter and been ingested into the engine as well as dripping out of the airfilter assembly.

Yeah, I know a lot of folks drain the sump if the bike's been sitting for an extended period but all my oil fittings are safety wired and I'm too lazy to fool with cutting and then refitting the wire every time.

In addition to hard starting and the oily mess, you can blow out the drive side oil seal if there is too much oil in the sump. I just fired up my 750 today for the first time since mid-July, and the entire contents of the oil tank had transferred to the crankcase. I drained it and put it back in the tank. With fresh gas, started first kick!

If it's been a while, I look inside the oil tank before starting. If I can see the strainer I drain the sump and refill the tank. If the level is above the strainer I figure it's ok to start it and let the oil get pumped back. Resurfacing my oil pump improved hot oil pressure a bit, but didn't make much difference on the wetsumping.

Debby

I resurfaced my pump on the rebuild, but my oil tank goes from F to off the stick in about 7 days. I imagine it's loose fitting gears. I'm going to install a valve with a kill switch because I won't be riding the bike that much and draining the sump is a pain. I'm hoping too that I won't be having all that oil out of the timed breather I have and into the air filter and then down on the gearbox and all over the bottom of the bike like it used to be.

Dave
69S

I continue to be baffled by all this concern about wet sumping and all the devices people search for and install to alleviate the problem. I have owned 4 Commando's over the years and never even looked to see if I have a wet sump condition prior to firing up. I have had my current bike sit for 6 months and fired her right up. If you have lived with your bike for a time, you know the required starting sequence to bring the motor to life on one try. Just let her tick over for a few seconds and the oil will be back in the oil tank. That is what the scavenge pump is there for. If you have oil squirting out the vent hose running from the top of the oil tank, I would imagine you have too much oil in there . I run a draft tube on mine down through the gearbox space and have never seen a drop from there. Keep it simple and ride it rather than work on it is my motto.

I'm just nervous. This thing hasn't leaked a drop since rebuilding and I remember it used to be if it wasn't leaking oil, it didn't have oil in it. I noticed when I split the crank, there was nothing on the flanges. I used Hylomar on it going back together.

Dave
69S

I forgot to put the oil tank drain plug after oil change yesterday. Poured 2 quarts of 40wt before I saw a puddle forming, then fumbled with the drain plug! :roll:

Ha, not much a mechanic if you ain't poured in new oil w/o sump plug in yet.

I"m mostly with aceaceca on fairly short term storage star ups. I do look in tank to see if oil enough for a few seconds idle before a pencil thick jet of oil retuning from breather hose of real Combats. But still can't have that in new Ms Peel so manual anti sump valve, ya can't kick lever until valve lever moved out of the way.

When seller of my pre-Peel, son of vendor in same building of the show room that sold it new, looked in tank then got 2 qts to pour in and started it on 2 kicks in pride blipping it till we saw two qts oil spreading out at our feet. He shut down sheepishly saying he'd toss in the free oil change too : )

hobot said:

Ha, not much a mechanic if you ain't poured in new oil w/o sump plug in yet.

I"m mostly with aceaceca on fairly short term storage star ups. I do look in tank to see if oil enough for a few seconds idle before a pencil thick jet of oil retuning from breather hose of real Combats. But still can't have that in new Ms Peel so manual anti sump valve, ya can't kick lever until valve lever moved out of the way.

When seller of my pre-Peel, son of vendor in same building of the show room that sold it new, looked in tank then got 2 qts to pour in and started it on 2 kicks in pride blipping it till we saw two qts oil spreading out at our feet. He shut down sheepishly saying he'd toss in the free oil change too : )

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Brain fade! That was the oil tank drain plug, not the sump drain! Guess you never did anything stupid!

Oh No - bmwbob - oil tank plug - thank goodness I'm not half the mechanic level you attained!

I just can't imagine a more involved funny story inducing to crazy making motorcycle than our Norton Commando's. Don't slip up around them eh.

hobot
PS i'm digging out of spoke nipples on 5th failed attempt with two types of blue silicone RTV. Not sure what next, fiber glass filled roofing tar or Hylomar?
Hylomar may be easier to clean out for next attempt of marred new rim.

"That is what the scavenge pump is there for. If you have oil squirting out the vent hose running from the top of the oil tank, I would imagine you have too much oil in there "


It is not squirting out of the vent hose in the top of the tank. It is spitting directly from the engine vent, which yours is doing as well (they all do) - But instead of running to the tank, my hose is attached to the vent and then runs directly to the rear of the bike. You are correct that it would not spit out at all if the hose was plumbed to the tank since the tank would accept the oil. But I wanted a freer breathing crankvent so that's the price of a hose directly from the crankcase vent to the outside without a catch can if the bike has been sitting long enough for sufficient oil to end up in the crankcase.

Always leave on compression and if it still wet sumps, get the oil pump reconditioned .

"Always leave on compression and if it still wet sumps, get the oil pump reconditioned ."

I resurfaced the oil pump months ago which reduced the wetsumping to the point where it's not an issue at all if sitting up to a month. But I have to admit I never bother leaving it on compression - I never seem to think of it.

debby said:

In addition to hard starting and the oily mess, you can blow out the drive side oil seal if there is too much oil in the sump. I just fired up my 750 today for the first time since mid-July, and the entire contents of the oil tank had transferred to the crankcase. I drained it and put it back in the tank. With fresh gas, started first kick!

If it's been a while, I look inside the oil tank before starting. If I can see the strainer I drain the sump and refill the tank. If the level is above the strainer I figure it's ok to start it and let the oil get pumped back. Resurfacing my oil pump improved hot oil pressure a bit, but didn't make much difference on the wetsumping.

Debby

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exactly the procedure I take as well. If the intake is sucking air you won't be getting oil where you need it. Not a big deal to drain the sump. These old gals can help their incontenence. Just another one of the joys of owning a Norton IMO.

"Always leave on compression and if it still wet sumps, get the oil pump reconditioned ."

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The only thing leaving on compression or exhaust stroke does is to position the crank with journals at their highest point. Considering the small volume of the oil passages in the crank, I doubt it helps much where wet sumping is concerned.

Last spring a half-dozen of us reported the actual wet-sump rates in our Commandos. In all cases, some effort had been made to reduce the effect (lapped pump, new Mk3 checkvalve, etc). The results among us were consistent, around 1 fluid oz per day. Thus a Commando left for 30 days would, on average, collect nearly a quart of oil in the crankcase. Rather than risk a surge of oil into my crankcase vent checkvalve, I always drain the sump when my bike is left unused for more than one month, although a simple check of the oil tank level, as Debbie suggests, confirms the need to drain the sump. A missing quart is easy to see on the dipstick.

Doesn't the engine always come to rest during a compression stroke? What else would stop its rotation when the ignition is turned off? Valve spring pressure on the cam?

The only time My commando sits for any period of time is over the winter and I always empty the sump in the spring. Other than that I have never emptied it and just start the beast. If you ride it regularly you wouldn't have this discussion, right. :mrgreen:

"If you ride it regularly you wouldn't have this discussion, right."

But I don't so I do.

I spend a total of 5 months of the year NOT where my Commando is.

That is sad

How much oil does a "key off" kick start scavenge? Suppose you just kick it over with the key off . . . . say 5 times?

Well... I don't allways believe in God but in the case of wet sumping I think this her way of telling us we need to ride more often.