750F1 breather plumbing

[FATAL]

my 1976 750F1 has a breather chamber (part no: 17262-392-00) situated next to the battery and rear of the air filter. There appears to be a number of pipes that attach to this unit. I  have identified the drain on the bottom , the top connector seems to attach to the top of the air filter box, but there is another pipe just above the drain hose, I dont know how long it should be, or where it connects to.
It is so long since I did anything to this bike, and even longer since I pulled it apart I now seem to be having a number of senior moments.

I'm thinking that the pipe may connect to the crankcase breather at the rear bottom of the crankcase, if so the breather pipe that leaves by way of the rear of the rocker cover then just hangs loose down by the swing arm, am I correct? I somehow doubt it.
My other concern is that the sponge breather element has perished with age and is now unavailable, any suggestions for a replacement?

Is it feasible to discard the breather element unit, seal off the connector on top of the air filter box, but then where do the crankcase breather tubes route to. I'll be most obliged for some help on this issue as plumbing is not my forte.

[Spitfire]

Hi Fatal,
            Had a good hard think about this when I rebuilt mine, I was going to run the breather as per my K1 and K2, straight out of the rocker box to atmosphere and plug up the hole in the airbox. However I thought I would keep it standard, the spring and element in my breather pot had also disintergrated so it is just an empty pot. But it seems to work OK.
Here's some pics.

Cheers

Den

F2 layout, basically the same as F1

From the F1 manual

and the real thing

[FATAL]

Spitfire thanks for the prompt reply, I see by the pictures that the tube from the airbox goes to the connector on the top of the breather unit, does the pipe from the rocker box cover connect to the other lower connector on the breather unit?
I see that the very lowest connector on the bottom of the breather unit has a loose pipe which is the drain. It appears that the hose from the lower rear crankcase connects to the lower stub on the oil tank, is that right?
I may run without this if as you say the earlier models did not have it fitted, I'm not too bothered by deviating a little from standard spec so long as it will run OK.
Thanks again, Fatal.

[Spitfire]

As far as I can tell the small pot acts as a KO vessel, the vapours from the rocker box breather enter via the connection on the side of the pot, vapours go up and are fed to the airbox, any entrained liquid goes down. At the bottom of the pot was a drain to atmosphere, it was dual diameter, big bore where it connected to the pot slimming down where it was hooked on by the mainstand, it rotted away so I replaced it with some other tubing that I had.

Cheers

Den

[FATAL]

Thanks den, one last question, the large diameter pipe from the lower rear crankcase were does that connect t? In your photograph it looks as if it's going to the oil tank, is that right?

[Spitfire]

Yes that's correct, the photo below is a bit clearer.

Cheers

Den

[FATAL]

Thanks for that.