72 Crankcase RADICAL Modification

This is just great. We got a breather with a useless strainer and an oil pickup with nothing. Maybe the strainer on the breather was to keep crap from being sucked in since they pant like a dog in heat. Before the inline check they would suck and blow, now they just blow. With the cases being modded with the oil pickup now toward the rear, there is still nothing keeping whatever that could get in the crankcase (or are assuming this is a sterile environment) from being suck into the oil pickup circuit. God help us for I feel we with 200000 series units are living on borrowed time. More and more I believe the Combat got a bad rap.
This is what I propose and where I need some advice.

Were the castings of the 200000 series cases left with the boss area of the before and after incorporated sump strainer and if we are willing to go to the lengths that we already have, why not go a little further and re-incorporate the sump strainer? A little milling, a little drilling, a little tapping ,,,, ta da.

Anyone got a blown donor, I will pay the shipping, do all the work, and report any successes or failures.

If the castings were too radically changed…….then ……..never mind.

Don’t get me wrong, I love my 72. It’s the hobby of a life time. Had it up to 95mph last night.
The bike is 38, I’m 56,….Christ, what a rush.

I think you're overthinking this whole thing. This from someone who overthinks everything. :mrgreen:

1. Leaking engine? Yes/No?

If yes, a one way valve on the breather may help.
If no, ride bike.


2. Evidence of oil starvation? Yes/No?

If yes, a revised pickup may help.
If no, ride bike.

See, simple. :mrgreen:

Thanks dave. Can you answer my question?

I agree with the swooshmeister. You have me so confused now... What was your question?

Russ
'72 Combat so far unmodified

batrider said:

I agree with the swooshmeister. You have me so confused now... What was your question?

Russ
'72 Combat so far unmodified

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Were the castings of the 200000 series cases left with the boss area of the before and after incorporated sump strainer? In this case machining could be performed to re add the sump strainer from previous and later models.

pvisseriii said:

batrider said:

I agree with the swooshmeister. You have me so confused now... What was your question?

Russ
'72 Combat so far unmodified

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Were the castings of the 200000 series cases left with the boss area of the before and after incorporated sump strainer? In this case machining could be performed to re add the sump strainer from previous and later models.

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Why do you want a sump strainer?

swooshdave said:

Why do you want a sump strainer?

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There is nothing keeping whatever that could get in the crankcase from being sucked into the oil pickup circuit or are we assuming this is a sterile environment. And then I guess we really don't need a magnetic plug either. Is this YOUR contention?

Again, humor me, can you answer my original question?

pvisseriii said:

swooshdave said:

Why do you want a sump strainer?

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There is nothing keeping whatever that could get in the crankcase from being sucked into the oil pickup circuit or are we assuming this is a sterile environment. And then I guess we really don't need a magnetic plug either. Is this YOUR contention?

Again, humor me, can you answer my original question?

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My contention is that if you are unsatisfied with the design of the 72 crankcase, sell the engine/bike and get something else. You also have the choice to modify what you have now. If you are wondering if the 72 case you have has the casting for a sump strainer, stick your nose under YOUR bike and look. :mrgreen:

If you want to tear your bike apart and make these modifications, feel free to do so. No one is going stop you. It's your time and money.

From a practical standpoint you have a nice running bike that will last for many, many miles without you doing much more that change the oil. You perhaps don't understand how fortunate you are.

If it were me, I'd be out riding the shit out of the bike but I have to build mind first. :mrgreen:

Thank you, Dave, for your very constructive Criticism. I know I should be satisfied and grateful for what i have but you know how us tinkerers are.
Thanks again,
Respectfully,
Peter

OK OK guys, The answer to your question is NO!!! Dave has a point in that these models will run great without any changes as long as you don't run it like a bat out of hell for long periods, You just stated you had it up to 95 last night and it still runs, Right? I think the reason the breather is missing the filter is because it will work better without it, We all know that a lot of oil gets pushed up though it at high rpm. Just think of whats happening when oil and air are trying to move past that filter, Your not moving as much air as you can without the filter in there. That's the only place on the engine that air can escape, And this is why the fix many use is to block off the rear breather and move it to the timing chest, And block off the front oil pickup. This makes the engine just like the 850's just without the strainer in the sump. As far as the magnet goes, I don't think it is used to catch big chunks of steel. If this is happening you have bigger problems. And the sump filter will not catch small microscopic stuff anyways, That's the purpose of the magnets. The best thing you could do is fit a filter and keep clean oil in it. Here is a great idea for our machines if you are worried about crap in your oil. http://www.magnom.com/index.php/info/product/mini/ And this is about all I have to say about this, LOL LOL. Ride safe guys, Chuck.

pvisseriii said:

Don’t get me wrong, I love my 72. It’s the hobby of a life time. Had it up to 95mph last night.
The bike is 38, I’m 56,….Christ, what a rush.

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Just to lighten the mood a tad I have just got in from a ride up the M20 in the pouring rain...when on overtaking a large Sainsburys artic my Mikuni 38 stuck open
...........I can now state with absolute confidence that the Air Filter I am using will pass the WOT test at 6500 rpm, and that Avon Road Riders do not white line.....

pvisseriii said:

If you don't know, Dave, it's ok. But to assume others are foolish can only expose your own inadaquecies, like sending out a project for powdercoating without mocking it up first.
Please remove your posts so that others won't be insulted or confused by your rantings and I will delete this comment.

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<edited by swooshdave to remove childish remarks. swooshdave promises to play nice although may launch into rants from time to time.> :mrgreen:

I understand completely the question...and if I had a blown, or for that matter good case sitting here I would try to help answer it. Some guys run without an oil filter, some wouldn't think of running without one. So there seems to be plenty of room for opinion. I for one applaud your couriosity and if you want to invest your time in figuring out how or if a sump screen can be added to the oil pick up then I will also be interested in your results as I too have a Combat case. This forum is great, but I am continually confused over how one arcane idea will get beat to death and another will be discarded as having no value.

With that said...lighten up boys...half the fun in is the tinkering and what good is tinkering if you can't explore ideas.

Somebody here hangs a large magnet in their oil tank and claims it helps keep the oil clean. If this is so then it would seem that machining a spot to put a large magnetic plug in the sump might be of value also. Its not a screen, but it might be easier to pull off.

As for the notion that if you have large bits that the problem is big enough that a screen is of no value, I would disagree, the last thing you need if your are experiencing something coming apart is for your oil pump to completely go away. It might mostly be luck, but it might also be the difference between the scrap heap or a rebuild.

If nothing else I would give Matt at CNW a call and ask him if they have ever explored the idea. I imagine he would take the question seriously and has enough experience to know if it is something that can be done without buying a different style case.

Have a good day!
Russ

For all interested, here is a reply from Matt at CNW.

"Peter,

In order to do what you are asking for, and using the same sump plug installed in the other model years, you would have to have more material thickness in that area to ensure that you get enough thread engagement for the sump plug and to ensure that it would sit low enough in the case.

The typical 1972 case is different then the others that you mention in that it is far thinner right where the plug would have to go. You can not just puddle and build up material due to the heat you would expose the cases to. They would most definitely warp. The option would be to weld a large aluminum part that was already threaded for the sump plug, maybe even a cut out of one of the other models you mention. You would still have to be extremely careful to not change the shape of the case while welding. You would be very close to the edge and when we weld in this type of material we bring it up to extremely high temperatures.

The second challenge would be that you will have to tie the old pick up tunnel with your new pick up area.

So the bottom line is that you would spend a whole lot of time and effort into what could possibly damage your cases. Whether or not this would be worth while to get some additional filtration I am not so sure.

Matt


Colorado Norton Works"

As for the notion that if you have large bits that the problem is big enough that a screen is of no value, I would disagree

Hortons Norton said:

As far as the magnet goes, I don't think it is used to catch big chunks of steel. If this is happening you have bigger problems. And the sump filter will not catch small microscopic stuff anyways, That's the purpose of the magnets. The best thing you could do is fit a filter and keep clean oil in it. Really don't know how you came up with that? We all agree that the sump screen is a good idea that is why Norton had them. I don't know where in my post I said they are of no value.

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Here is another reply from Fred Eaton at OldBritts.

"Peter:

Not enough meat in the crank cases to reinstate the sump filter.

Fred:"


All righty then, lets move on.