The Breather was Blocking the Breather. 1979 AMF XLH1000 Ironhead Sportster.

The reed had bent back and was closing the breather, resulting in an oil mist emanating from the crankcases (rear breather also found to be out of action, for complicated reasons).

[@FourIntoOne]

The breather to the oil tank is closed loop - not being able to blow thru it is correct - I would simply run the breather from the reed valve outlet to atmosphere somewhere rather than trying to splice it in with the line for the oil tank. If you think about it when the oil pump takes oil from the oil tank the air volume increases which allows pressure from the crankcase to be drawn into the oil tank - as I say closed loop- its continuous when the engine is running.

[@ImminghamIronhead]

Makes sense. I have the front one exiting into the air filter cover as before, and the rear one goes where it should now, with the addition of a further breather to atmosphere. May as well 🙂

[@MoeLarrycurly1]

Woo Ill be putting a reed breather in a bike . on my channel . bike ..area scorrd to much ..

[@matthewnaylor4412]

Do you have to slacken the push rods off to get that timing cover off? Stupid convoluted rear brake set up on 77 xlch with that splined lever goes through it to connect to cable on that steel sprocket guard?

[@ImminghamIronhead]

Yep, definitely slacken off the rods first; '77 rear brake sounds different to mine.

[@ludo9234]

Use a reed breather from a old royal enfield, just run the pipe to the back mudguard like the old Bonnie's had. Stuff paying that much.

[@ImminghamIronhead]

I'll look into that; the only Harley reed I could locate was in the US, so postage and import charges would have been astronomical for a twenty dollar part.