What would the symptoms be?? Heavy Breather plugs the breather holes. I've been off and on getting a sound like an excessively PO'd sewing machine, then it subsides. Sounds like something might be sticking a little and then re-lubricating itself. Would plugging the breathers cause this, or could it be an oil pump, sending unit, or inadequate pressure kind of thing? 2009 Nightster, about 8500 miles.

Sounds like an oil less top end for a bit, then sounds like a regular sporty top end, and back and forth.

 

Does it actually plug the breathers, or just reroute them into the filter element? If it is in fact plugging them (i.e. no exit at all), that would be dangerous. The pressures need to equalize, if they don't you could blow a gasket, seal, or something worse. I would make sure of this first, because if they are plugged they will cause damage at some point. Chances are it's just rerouted into the element, as many ACs have that built in. Can't say for sure if the HB is one of those.

That noise sounds exactly like the description of hydraulic tappets running dry. The oil does not get in, and thus the pushrods bounce around a bit instead of riding on the oil layer, and it makes a heck of a lot of noise. Often happens after long storage because the oil has seeped out and takes some time to get back into the tappets. If this is a recurring problem, you or someone qualified, should take a look at the tappets. The oil fill hole could be clogged or malfunctioning. May be ok for now, but will cause damage long term if not fixed.

 

Thanks for the reply. You are correct about the tappets, BUT what can cause a "clog" or blockage that could reduce the oil pressure up there? The Heavy Breather uses "I think" the factory air cleaner assembly bolts, but has a double O-ring seal on each of the chrome pieces that cover the bolt. This pretty much seals it up tight. There is not a way, without modification, to vent the breather tubes back into the intake.

Could the "plugging" of the breather cause a reduction of pressure in the top end? Or should this be a warranty job??

 

just spoke with the stealership, and will be dropping it off tomorrow. Ill let everyone know what they find, if anything.

 

If those breathers are plugged off solid and not venting into the atmosphere or the intake. Thats your whole problem right there the breathers must do one or the other.

 

+1 - you can't plug the breathers and not have serious problems.

 

I've done some research on the Heavy Breather from Harley. The breather bolts are supposed to have a small passageway the routes back into the backplate/carb somehow. They are supposedly very hard to see, but are there in the breather bolts. There have been instances of instructions saying to use the wrong bolts. I would check into it, possibly disassemble if you have to in order to verify the breathers are open, or to fix it with the correct ones. Good luck, and I hope the dealer gets it right for ya!

 

any updates