Wet dumping/crank oil seal?

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I’ve been away on holidays for 10 weeks and the Commando hadn’t been ridden for several weeks prior to then. I accept that over that period of time it will wet sump, and I have a sump drain bolt setup already added. Obviously it would have been more appropriate to drain the oil prior to departure, but I didn’t think to do it. It was therefore left for about 4 months in total with a full tank of oil.

I‘ve come back to a small oil deposit under the chaincase :confused: and yesterday drained the sump. Today I’ve removed the chaincase and wiped up a small amount that hadn’t yet seeped out of the air holes. I’m running a CNW starter/ billet dry clutch etc. so oil is a no-no.

I replaced the main crank seal 500 miles ago and I am confident it was secure and properly fitted on a 11000 mile engine. The 3 crankcase to engine bolts are dry.

My question is this: Do I simply accept that under normal circumstances a new seal will always pass a small amount of oil, and that because it has been left for such a long time full of oil, that it is to be expected? If so, then I’ll just leave the sump bung open with a catch tank under it.
 
Landspeedracer said:
I’ve been away on holidays for 10 weeks and the Commando hadn’t been ridden for several weeks prior to then. I accept that over that period of time it will wet sump, and I have a sump drain bolt setup already added. Obviously it would have been more appropriate to drain the oil prior to departure, but I didn’t think to do it. It was therefore left for about 4 months in total with a full tank of oil.

I‘ve come back to a small oil deposit under the chaincase :confused: and yesterday drained the sump. Today I’ve removed the chaincase and wiped up a small amount that hadn’t yet seeped out of the air holes. I’m running a CNW starter/ billet dry clutch etc. so oil is a no-no.

I replaced the main crank seal 500 miles ago and I am confident it was secure and properly fitted on a 11000 mile engine. The 3 crankcase to engine bolts are dry.

My question is this: Do I simply accept that under normal circumstances a new seal will always pass a small amount of oil, and that because it has been left for such a long time full of oil, that it is to be expected? If so, then I’ll just leave the sump bung open with a catch tank under it.
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See if it repeats. Sounds like a minor inconvenience at this point, not worth a special trip into the primary.
JMWO
 
Oil may have seeped past the oil seal. A small mark on the crank etc is all it takes. It’s not really desgined to hold back a sump full of oil for ever, whilst stationary, so I wouldn’t fret yet, use it and see what happens.

What breather are you running? A reed valve breather can make all the difference here when in use.
 
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That’s what I’ll do then, and monitor it. But as I will definitely drop the sump plug if I’m not using it then I won’t expect to see anything.

I do have a Reed valve breather fitted in the system :)
 
cjandme said:
I'm not so sure that leaving the sump plug out with a catch can underneath for any length of time, is such a good idea and all, since it means that everything is exposed to the atmosphere / humidity.
Click to expand...
OK, how about a threaded hollow stud wound into the sump hole and a length of tubing running into the catch tank into a small amount of oil. Sort of like when you bleed brake lines.
 
EstuaryBoy said:
What about?.................
................some sort of on/off tap in the oil line????
(Can I patent this?)
Click to expand...
Wet dumping/crank oil seal?
 
Mechanical ball valves on the oil feed line without a warning system of some kind are only for really ignorant people that "can" remember to turn them on and off at the right time. They do work at preventing wet sump better than any other solution. I would never recommend one even though I use one. Motor hasn't blown up yet. I used the ball and spring long ago and it was useless over long periods of time. However, the ball and spring is obviously considered the intelligent man's choice.

Draining the sump into a catch container via a little tube attached to the sump plug drain while away for extended periods of time would be good enough IMO. And never leave the bike parked on a side stand if possible.
 
Did you smell the oil or note the viscosity? Are you sure it's not migrating out of the gearbox?
 
Since OP already has a lot spent at CNW with the estart, should spend a little more to the much touted CNW/Comstock breather valve sump fitting.

I'd guess he has over pressurized the sump when cranking fully flooded with that powerful starter. I blew my crank seal in half from a wet sump kick start.

AWSV with ign interrupt solved this nicely for me.
 
How did you come to the assumption that I’d over pressurised the sump etc. that you’ve just mentioned? :rolleyes:

if you read all of the words, you will see I said I came back to a small oil deposit ie perhaps 3cc/4cc under the bike, then I drained the sump of a normal oil tank’s worth of oil, then I removed the chain-case and wiped up another 3cc/4cc.

It is quite clearly engine oil, coming from the front end of the engine and black. Unlike the clear gearbox oil that I filled it with only recently, the gearbox doesn’t leak.


Perhaps in order to allay any more fears, I will put it all back together, then refill the oil tank and go for a ride. If I think the bike won’t move for any length of time then I will drain the tank and/or remove the sump bung.
 
That's been my plan for winter storage or any extended layup.
Just drain the oil tank , pull the plug wires and sticky a note on the speedo. Even if the mind is totally blank in the spring, the note and dangling plug wires will bring it all back.

If only I could remember to actually do the drain& prep at the end of the riding season.....

Glen
 
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Why not do the check valve in the timing cover? Why Norton didn't do that from the beginning is beyond me. Harley Davidson figured it out in the 1930s.
 
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