Crank Oil Seal leak
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B+Bogus said:
Well, in proper English, comnoz has qualified the use of "all rubber seals" and that he has seen them harden over time. My applications are race bikes only. I don't mess with my street Commando as it does not need messing with.
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comnoz said:
Yes, I recall this in 2013 at NJMP as well as at Barber. Jim, do you know if this instance was ever resolved. I don't recall any haywire arrangement on this side care instance. Was this an instance of poor venting or excessive blow by or a combination of both? I thought the rider believed the seal may have been spinning in the cases!?!?!?
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Dances with Shrapnel said:
I looked at the seal that had been removed at Barbers and it looked well polished on the OD. The new seal was installed without anything to hold it and continued to leak at that time. I don't know if the problem was ever resolved or not. Jim
Onder
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Partial reply so to speak on this.
Differential tester is inop so on its way for repair. I simply went to TDC and put 90 psi on it.
There is leakage past the rings, you can not only hear it but you can hear it pass on out through
the Jim breather to the oil tank and then out the oil tank vent tube.
However, I noticed no weepage or blowby of any kind in the seal area and the primary is entirely
stripped so I can observe it all carefully.
Yes I ran in the small primary inner retaining bolts before testing.
The bike has impressive compression at the kicker but without a diff test it doesnt mean much.
When doing airplanes you can back off TDC just a wee bit (lot of leverage using the prop) and
then push the pot up against compression and seat the rings more thoroughly at times. We used
80 pounds as a standard.
When the bike starts, usually wet sumped, you can see the breather valve pumping oil up and out
into the tank until it and the oil pump remove most of the oil. I don't see the valve being a problem
at this point.
Oh, the oil is certainly coming from the crankcase if not 110% sure it is the seal yet. Im using a TTI
box and it doesnt leak at all so far. The dry belt is why I spotted the oil to begin with, it is always in
the front of the primary and then migrates along the bottom of the giant o ring.
Im not yanking out the crank seal until Im sure this is the problem. Guessing is good for starters but I
need to be sure of what I know and what I dont know. It might be useful to fill the crankcase with oil and
introduce a light over pressure to it and see if it wiggles out the seal.
Ill add insult to injury and tell you the Royal Enfield fired first kick and I went out to put on 80+ trouble
free miles in 40F degree weather!. English bikes love the chill.
Ill get back to the list on this probably in a few weeks. Thanks for the help it is appreciated.
Differential tester is inop so on its way for repair. I simply went to TDC and put 90 psi on it.
There is leakage past the rings, you can not only hear it but you can hear it pass on out through
the Jim breather to the oil tank and then out the oil tank vent tube.
However, I noticed no weepage or blowby of any kind in the seal area and the primary is entirely
stripped so I can observe it all carefully.
Yes I ran in the small primary inner retaining bolts before testing.
The bike has impressive compression at the kicker but without a diff test it doesnt mean much.
When doing airplanes you can back off TDC just a wee bit (lot of leverage using the prop) and
then push the pot up against compression and seat the rings more thoroughly at times. We used
80 pounds as a standard.
When the bike starts, usually wet sumped, you can see the breather valve pumping oil up and out
into the tank until it and the oil pump remove most of the oil. I don't see the valve being a problem
at this point.
Oh, the oil is certainly coming from the crankcase if not 110% sure it is the seal yet. Im using a TTI
box and it doesnt leak at all so far. The dry belt is why I spotted the oil to begin with, it is always in
the front of the primary and then migrates along the bottom of the giant o ring.
Im not yanking out the crank seal until Im sure this is the problem. Guessing is good for starters but I
need to be sure of what I know and what I dont know. It might be useful to fill the crankcase with oil and
introduce a light over pressure to it and see if it wiggles out the seal.
Ill add insult to injury and tell you the Royal Enfield fired first kick and I went out to put on 80+ trouble
free miles in 40F degree weather!. English bikes love the chill.
Ill get back to the list on this probably in a few weeks. Thanks for the help it is appreciated.
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tomspro said:
Any bearing dealer will sell them.
Just take the old one in or check the dimensions written on it. I can't remember the size offhand but it's something like 1 1/2" x 1 1/8" x 1/4"
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Sounds like you are being methodical and will eventually (hopefully soon) get the slippery stuff confined.Onder said:
What year is you Commando?
Question for Jim - down the road (hopefully a long road), how difficult to remove a metal main seal that has been treated with JB Weld on the perimeter?
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JBW is not that great an adhesive unless surfaces roughed up for it to grab into and is rather brittle in thin layers and only acts as a hard filler in this area so seal should pull out like normal. Mehtylene Cholride [Strypeeze] softens/dissolves JBW in case some JBW sticking around ya don't care to scratch out. JBW orginial hi temp takes some days to really set up to stay solid when heated toward boiling temps so maybe just didn't set up well enough before tested. Mystery may be helped if could determine whether leak occurs cold and still or only spun while heated. I could see me putting gas or diesel in with Cdo tipped over to DS. Might bejust a weep through a primary case mount hole.
concours
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Onder said:
At this point a dial indicator should be set up, measure radial runout. Also lift up and down to check for any looseness there. Set up and measure axial runout (end float) as well. I read that this is a fresh rebuild, but before you figure out what it IS, make sure of a few what it ISN'T. Doesn't take but a few minutes to check.
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tomspro said:
When I install a seal with JB weld I always wipe the excess from the outside.
The seal comes out with no difficultly. Just punch a hole and use a metal screw. The remnants of JB weld can be scraped out with a pocket screwdriver. It is just epoxy glue after all. No tougher to scrape than many sealants that have been there a few years.
The reason JB weld works is because it can handle the case temperature and stay strong. Most engine sealants do not do well when the temperature approaches 350 degrees. Jim
Onder
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Remember the engine is less than 1k miles since full rebuild. This is the second seal installed
following Jim's instructions to the letter. 500 miles or less on it.
Sure I could just pop out the seal and try again and that may work but I already tried the parts changing approach.
Better to actually ascertain the problem.
Interestingly, the valve should produce either a slight vacuum or at least much less crankcase
pressure. But the the lip type seal loses some of its effectiveness as there is less pressure
on the seal?
All this is just after supper prattle. I need to carefully check everything out.
I will get back to everyone on this.
following Jim's instructions to the letter. 500 miles or less on it.
Sure I could just pop out the seal and try again and that may work but I already tried the parts changing approach.
Better to actually ascertain the problem.
Interestingly, the valve should produce either a slight vacuum or at least much less crankcase
pressure. But the the lip type seal loses some of its effectiveness as there is less pressure
on the seal?
All this is just after supper prattle. I need to carefully check everything out.
I will get back to everyone on this.
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Ugh, if less pressure inside keeping seal from sealing it'd only let air in not oil out so keep on stewing and what's spoiling your nice clean belt finish. Worse case I can imagine would be too tight a belt when heated tugging crank enough to weep through a case fracture.
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I would agree.
One other thing you might look at before you go back to the seal.
Is the scavenge pump keeping up with the oil going into the motor.
Watch the return flow into the tank. It should be mostly oil with lots of air bubbles.
If you are getting a lot of pure oil without bubbles, then the pump is not keeping up. Jim
One other thing you might look at before you go back to the seal.
Is the scavenge pump keeping up with the oil going into the motor.
Watch the return flow into the tank. It should be mostly oil with lots of air bubbles.
If you are getting a lot of pure oil without bubbles, then the pump is not keeping up. Jim
Onder
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Pulled seal. Seal looks ok and it was nicely potted with JB
around the edge.
The crank, inspected with a light and glass, shows minor
corrosion in one area. However careful measuring says it
is outside of the seal contact area.
I will have a look at the return oil but memory says it is
as you wish it to be. Once back together I examine this
too.
around the edge.
The crank, inspected with a light and glass, shows minor
corrosion in one area. However careful measuring says it
is outside of the seal contact area.
I will have a look at the return oil but memory says it is
as you wish it to be. Once back together I examine this
too.
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