K and early XL oil-tank drain down

Production K Models

K and early XL oil-tank drain down

Postby John R » Fri Aug 29, 2014 6:28 pm

When I first had my KK, if not used regular it would drain the tank into the engine in about two weeks! At that time I wasn't aware of Harley's first theory on this so milled the oil pump body to take the later drive shaft oil-seal 26227-58. That fixed it! The oil must have been seeping from the tank (open to the feed gears), though the clearances between gears and body via drive shaft clearance (whacking great slot for roll-pin) into the scavenger gear compartment which is permanently open to the gear-case. Assembly is a little fiddly as the second roll-pin can't be fitted till the shaft it fully installed.

However, Harley's first solution in '55 was to do away with the over-pressure by-pass valve. They theorised that this, also being open to the oil tank, was leaking oil past into the gear-case. All I can say is that my '53 with seal installed doesn't leak-down anymore, so it can't have a leaky by-pass valve.

In the same way, if the check-valve doesn't seal properly, this too can provide a drain-down route. And I guess this is the problem with my '56. There's no by-pass valve, I've installed an oil-seal and it leaks down a lot in about a month. This I can live with as it won't be often it's not run at least every fortnight.

In short, the oil-pumps benefit from close inspection and perhaps careful lapping-in of the seats. I have a check-valve ball silver-soldered to a rod ready for if I ever take it down.

Having said all that, oil pressure without the by-pass valve is massive on cold start-up - about 85psi! Guess what, base gaskets weep till oil warms, then the pressure's down low - about 6psi at 40mph.

Talking of low pressure when hot, apart from the obvious factors, some aftermarket gaskets are too thick. The OEM ones are about 3.8 thou, aftermarket up to 7 thou (the one between the pump and engine case is correctly thicker). The gears are flush with the pump body, so gasket thickness is the running clearance - too much clearance equals low pressure.
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Re: K and early XL oil-tank drain down

Postby dr dick » Sat Aug 30, 2014 1:14 am

could the by-pass deletion be hand in hand with the intro of the transfer valve and its now lower position in the crankcase?
i belive it is.
both these things kept oil volume in engine lower during sumped startup. hence reducing the tendency to puke?
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Re: K and early XL oil-tank drain down

Postby 55khkjoe » Sat Aug 30, 2014 8:49 am

When I bought my 55 it was a new motor sitting on bench. Yes paying more attention to the oil pump on rebuild is vital on K motors. but I am not yanking motor to go over it. I did look at the differences on Scotts oil pumps particularly the 55 pump and 56-58 pump and the relief valve discontinued in 56 to stop oil drain. Does any body have a K model service repair factory manual, I sure would like to see the oil system exploded view prints. Recently I went over my clutch, installed new kevlar discs and a new hub. Bike was sitting level on a stand for about 2 weeks waiting for parts. The transfer valve in the left case on 55 up motors was a constant slow bleed to the primary literally draining the oil tank. So this is when I drained oil tank and put a shutoff on the oil feed line like I did on my 53KK, I know of 2 other guys riding K's for years who also do this to stop the bleed. So for now this works, I doubt I will ever yank motor on the 55 but if I ever rebuild another K, I will do more research and try to cure the bleed from the source the oil pump.
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Re: K and early XL oil-tank drain down

Postby hennesse » Sat Jan 30, 2016 7:13 pm

Tom wrote:Tif they leak down V Twin has a seat cutter that works great- I have one and have corrected a seat problem on other pumps with it


Is this the animal? http://www.vtwinmfg.com/webapp/wcs/stor ... Id=3295249

Some good ideas here: http://knuckleheadtheology.blogspot.com ... cheap.html
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Re: K and early XL oil-tank drain down

Postby thefrenchowl » Sun Mar 27, 2016 11:28 am

Agreed, Tom,

But remember, these bikes weren't always collector's fancy bit on the side, and at one stage, horror, get into the time machine, were used everyday in which situation sumping just does not happen... Not to mention oils of that time were much thicker than today's... By today's whims, the K should never have existed... ; - )

So don't be too quick in blaming the engineers or a lack of knowledge... They were highly qualified, of German descent for most of them, and knew exactly what they were doing and designing... The way the oil system work, from 1936 WL to last 1976 Sportster is proof enough to me!!!

To machine the pump and supply a seal cost money, and to start with, they just ignored the seal...

It has to be said as well the eng. dept. would have rather preferred playing with the OHV KL at the time, modern, stylish, blablabla... so maybe they knew but just nodded in agreement with the management' decisions, the Harleys and Davidsons saw the K SV as their saviour... MAKE IT CHEAP...

There's always more than one way to skin a cat... And insight into the past is not proof that you would have been right!

Patrick
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Re: K and early XL oil-tank drain down

Postby thefrenchowl » Sun Mar 27, 2016 4:08 pm

I repeat Tom, and please chill out!!!

Don't try to understand 1950s engineering with 2016s thinking, it won't work and on top of that, you won't really appreciate what you're looking at... Be humble and willing to learn when you look at old stuff...

Engineering is the science of COMPROMISE... Nothing, but nothing, is ever 100% right or 100% wrong... The solution always lays somewhere in between.

Now show us a bit of what you do, how you do it, and you might gain one reader ; 0 )

At the moment, it's a bit too much of "do it my way or not at all but I won't show you my way"!!!!!!

Now, I'm sure that if you applied for a job at Harley, they will give you one no doubts...

So I've done it my way, with help from proper old timers and thinkers, for the best part of 50 years, you do it yours and we'll leave it as that... ; 0 )

OK???

Patrick

PS: And you really think you are the 1st guy ever that has looked at a WL, K or XL oil pump??? On what planet are you living????
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Re: K and early XL oil-tank drain down

Postby thefrenchowl » Sun Mar 27, 2016 6:53 pm

YYYYAWWWWNNNNN
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Re: K and early XL oil-tank drain down

Postby sportsterpaul » Mon Mar 28, 2016 4:55 am

Tom has a point if you can see past the fleck of spit as he yells at us. Yes, the seal between the scavenge and return sections greatly reduced sumping. And Tom is right that the ball valve is not the only thing to tend to. But let's face it, you can mess with the ball check without pulling the engine from the frame, so that is a good place to start. There must be a reason the factory manual talks about lapping the seat.

I am a bit confused Tom, when you say that if you have a good seal between scavenge and feed, and if you have dealt with the ball check, then you have a case problem. Yet you are the same guy that points out there is no seal above the pump gears, where the timed breather is. It sounds like Tom was like a lot of us, who thought that a ball valve re-seat or lap would solve the problem, and when it didn't for him, now he things lapping the ball check seat will never work. One man's truth is not all men's truth.

As to why Ks and Sportys sump, well yeah, the ball check is one problem, and that seal is another, and Tom is right that there is no seal above the pump gears to the timed breather. I think a lot of us forget just how old and worn out some of these bikes are. I suspect that they added the seal because it took a short time for the housing to wear enough to allow more oil to weep. I feel confident that a timed breather that is tight to the housing will weep a little, Tom is right, oil gets everywhere. But I think a new tight breather will not weep enough over a month or two to sump the engine. Dr Dick, like always, is right too. By letting the transfer valve pass some of the crankcase oil into the primary, it lets the bike start without puking out the breather tube, and then the oil can slowly work its way out of the primary to the crankcase and then out the door.

Bill's Custom Cycles sells new 1000cc pumps, and they claim that they solve a lot of problems. I can believe it. With tight tolerances between the gears and housing, and the timed breather and housing, and a new seat for the ball check, I am sure this can make the pump work as those Harley engineers intended.

Be sure to check out the tech area where Dave H has posted a picture of Scott Lange's pump collection. This seems to show the seal between feed and scavenge starting in 1958. It also shows the wider hole in the rotating breather coming in 1962, which astonishes me, I thought it was 1972 for the 1000cc engine. It does show a new steel housing in 1972, and that must have the wider hole I was thinking about-- I assumed the rotating part and housing changed at the same time. Live and learn.

Another oil system problem I see is because I never check the fit of the rocker arms on the shaft. There is a reason the factory specs this, but how many of us are willing to push out the bushings, install new ones, and then hone them to the tight fit demanded by the specs? Yet I worry about the 0 psi oil pressure I get up there when the bike is hot. Not the end of the world, Sportys are a flow system more than a pressure system, but if those rocker bushings are all leaking, that is robbing oil from the spitter aimed at the exhaust valve. And I have never taken a bike apart where those spitters were not blocked by some small grunge anyway.

What would be neat is to measure these problems. Put a pump together, and apply oil at a psi or two, and see where it leaks out, and how fast. Same for the rocker boxes. You could them measure the cc's per day, and have some idea how bad the engine will sump. I am sure my sumping is worse because I run 20W-50 instead of straight 60-weight.
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Re: K and early XL oil-tank drain down

Postby thefrenchowl » Mon Mar 28, 2016 6:42 am

That's the point, Paul,

I don't want to hear a guy yelling at me stuff I found by myself, no net then, 30 years ago...

To me this stuff is so obvious, I don't even talk about it cause I assume rightly that everyone by now interested with these old bikes will have heard of them...

I did not shout back, just pointed nicely at all the other points of view...

This is yet again turning in another "what oil should I use" or "can I use compressed air to fill my tubes" discussion... ; 0 )

More to the point, no one will ever be able to fit a seal between feed gear and tower...

Others and meself have looked at it, there's just not enough meat there...

So the one and only sure non sumping thing to do is to fit a valve or a Velocette type spring ball assembly in the feed line...

Guess what, all me bikes have a valve and they don't dump their oil...

Now, I can run my oil pump quite loose (less eaten BHP...) and I'm happy as Larry.

Do I tell you to do the same? NO....

You can do whatever you wish on your bikes, but in my book, the foolproof and cheap option will always win the day!!!

That allows me more time on more complicated stuff like twin carb manifolds, reverse machining of DC carbs, modify gas carbs to accept methanol or supercharging the whole job...

So long, have a nice Easter Monday, back at work tomorrow and this 55KHK is calling me now!

I'M COMING, DARLING!!!!

Patrick
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Re: K and early XL oil-tank drain down

Postby thefrenchowl » Mon Mar 28, 2016 11:31 am

Hi all,

So Tom, where's your tech posts and photos about all these wonders you design and make so we can learn from your all embrassing wisdom???

Start also behaving like a proper human, say hello and goodbye, think twice about what you write down, don't look down at people and assume everybody but yourself is a moron that deserves insults and short drift...

Until such times, I can only you on my ignore list...

Patrick

PS: you can fan and fart about all you want with the oil pump, you're still way dearer and you won't beat my price of a simple ball valve in the feed line : 0 (

... But I forgot, you so way up there in the stratosphere you'll forget to turn it on, SILLY ME...
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