Primary fill plug spitting oil

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Primary fill plug spitting oil

Postby jjohnson1177 » Fri Sep 09, 2016 6:44 pm

Greetings guys! I have run into an unusual problem with my 54 KH. When it is running it starts to spit a little bit of oil which turns into a stream out of the primary fill cap. It has the proper amount of oil in it in the plug is in good shape so I am sort of at a loss as to what this might be. I have never run into this before. Thanks in advance for any replies or suggestions.
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Re: Primary fill plug spitting oil

Postby EKHKHK56 » Fri Sep 09, 2016 7:56 pm

Hello. Does the system have too much oil in it? It should be way below the filler plug...Ks can bleed oil into the crankcase when sitting than when you check the tank it appears low. Adding to the tank will overfill the system at that point. Erik K
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Re: Primary fill plug spitting oil

Postby jjohnson1177 » Fri Sep 09, 2016 10:10 pm

Fellas I'm going to pull the outer primary cover off tomorrow. The oil amount was correct and its not sumping. I'm thinking there should be a vent screw in there but there might not be. There have been several issues with this bike since I bought it so it may not have been assembled correctly.
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Re: Primary fill plug spitting oil

Postby jjohnson1177 » Fri Sep 09, 2016 11:30 pm

That's what I'm thinking Tom. I don't think that piece is in there.
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Re: Primary fill plug spitting oil

Postby hennesse » Sat Sep 10, 2016 2:48 am

Hi,

John R, or maybe Dr Dick, posted a seminal article on this forum about the oil transfer valve. I'm not too sure of the details, but here's my understanding. The engine can wet-sump a little, and the excess oil will be blown into the primary case, which has lots of volume to absorb it. Once running, the engine will slowly suck back excess oil from the primary into the engine. The 1952-1954 was a primitive system, with major improvements in 1955 (or very late 54's with the removable transmissions).

The 1954 Spare Parts Catalog (SPC) shows the often-lost, and very hard-to-find parts shown below. There were not in the 1953 SPC, so they must have been introduced mid-1953, and used through late 1954. In 1955 they went to a different system. See the SPCs over in the Literature section.

25100.jpg
1954 Spare Parts Catalog
25100.jpg (79.63 KiB) Viewed 17431 times


I believe this tube was used to suck oil OUT of the primary and back into the engine. There seems to be some disagreement about what o'clock the tube should be facing. I'm finishing up my chassis before assembling my engine, so I do have one, but not sure which way it goes. But I believe it should be pointing towards the bottom of the crankcase. If you don't have this tube, and perhaps more importantly, the check valve, you may be blowing all the oil out of the crankcase into the primary, with no way to suck it back - and your primary filling up.

The early oil pumps has a check valve and a relief valve. These both used a half-ball bearing attached to a "stalk", with a spring. 1955 and later models went to a plain ball bearing and a spring, and then the relief valve got eliminated. For your 1954, you need to find a good welder dude who can weld a thin rod onto a ball bearing, so you can use this with valve grinding compound to lap the check/relief valves in. The Sportster Service Manuals tell you to whack the ball bearings into the seat with a drift - a little more brutal method. But for the 1954, you need a good welder dude.

If your cover is badly worn, you might try one of Tom's modified covers. But first, I'd work on your check/relief valves.

Dave
Why, oh why, did I pick a 1954 KH to restore...
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Re: Primary fill plug spitting oil

Postby JohnF » Sat Sep 10, 2016 7:19 am

Reading the last post, there is an easier method to lap the oil pump ball seats, verses welding. Mix up a little liquid steel type epoxy and use it to attach a metal pin/drill bit to a spare steel ball. Used this often and it's now one of my "special tools". I' m using a 57 to 60 oil pump on my 54 with success. Little tidbit found in the "What Fits What" Harley booklet.
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Re: Primary fill plug spitting oil

Postby jjohnson1177 » Sat Sep 10, 2016 11:09 am

Ok guys, my pump isn't sumping, I had the measured correct amount of oil in the primary, and my oil tank isn't losing much. Anyway, all the parts are in the primary like they are suppose to be, the one way valve is in the fitting with the tube and it will only pass air from the crankcase into the primary case. It seals up fine the other direction when you blow into it.
Now here is a thought. If my breather on the oil pump isn't timed correctly could that be causing enough pressure to cause my issue? What makes me wonder about this is that the cam cover gasket is seeping some also as well as the lifter bases. Like I said earlier, the old gentleman who is a very good friend of mine built this bike over 20 years ago, way before I bought it and never ran it. I've had to fix wiring issues, make adjustments ect. but it's all coming together just slowly lol. One last thought also, the breather assembly was in the bottom hole of the primary chain adjuster. The parts diagram shows it looking like its in the top one. Could that make a difference? Thanks again for the replys and thoughts on the matter:)
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Re: Primary fill plug spitting oil

Postby jjohnson1177 » Sat Sep 10, 2016 2:07 pm

Just to make sure , you're saying the one way valve should vent from the crankcase into the primary case?
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Re: Primary fill plug spitting oil

Postby EKHKHK56 » Sat Sep 10, 2016 2:48 pm

I believe the one way valve is supposed to use negative crankcase pressure to pull excess oil from the primary area and put it in the return system. If the level is above the valve than it should pull that oil into the crankcase and return it. Erik K
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Re: Primary fill plug spitting oil

Postby EKHKHK56 » Sat Sep 10, 2016 2:52 pm

Breather timing needs to be correct yes.
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