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Hi.has anyone had issues with oil blowing through breather pipe into the air filter ( 1997 roadking injected) what causes it and what’s the fix.??
not a mechanic 😕
Mike …Uk
Hi.has anyone had issues with oil blowing through breather pipe into the air filter ( 1997 roadking injected) what causes it and what’s the fix.??
not a mechanic 😕
Mike …Uk
The TC and most all do it to some degree. If you have the open exposed filter, it will drip thru.
Atmosphere pressure is going into intake, so little oil actually goes into engine.
High RPM and then sitting will let oil run down into air box.
Just wipe the drool off the old girl's chin and keep getting up.
More oil leaks past ring gaps the and going into intake.
The one way out poppet valves in the heads and a 180 degree loop thru a small mesh screen is pretty small. Valves just stop air from coming back. They don't stop exit.
Lot of closed throttle engine braking tends to make it worst.
It hurts nothing.
PS.. your old Harley has a breather timed valve in cam galley. I am not exactly sure how it vents thru the heads or from vent hose off engine case.
Last edited by Jackie Paper; Jun 4, 2024 at 12:11 PM.
Yes, run a little less oil and it will get better. You'll have to experiment to find the sweet spot. The service manual for my limited says 4qt with filter which is way too much. I was seeing alot of oil residue under breather and a few stains on my pipes, would wipe out the breather cover with a rag after each ride to cut back on what gets on motor. I live on a short stretch of gravel so the dust sticks to the oily surface and look like s**t. Started cutting back 1/4 qt on oil at each change and 3 1/4 qt has almost eliminated it entirely and it still measures upper middle of the dipstick
Might be time for new umbrella valves. While you have the rocker boxes open you might consider drilling the oil return holes slightly larger.
I fixed my minor issue like this.
Hi.has anyone had issues with oil blowing through breather pipe into the air filter ( 1997 roadking injected) what causes it and what’s the fix.??
not a mechanic 😕
Mike …Uk
Three problems, and the first will the umbrella valve in the rocker cover middle plate has become hard, and really needs to be change out with new OEM ones.
The middle plate will have the umbrella valve just above the breather port side (both cylinders get it installed on the intake side of the jugs) and when you change them out, do not need to pull the lower rocker assembly bottom plate off the head, just replace the center plate lower and upper large O ring type gaskets, and pick up the top bolt gasket washer at well. And get the new umbrellas and gasket from HD, since the JG ones are junk and will just cause problems. https://www.sportsterpedia.com/lib/e..._phillober.jpg
The Second problem is epa does not allow the vapor that is going to be pushed out of beeathers to be dumped to the ground, so HD piped that vapors into the air filter area, to be sucked in by the engine to be burnt up in the cylinder instead. So still going with EPA guide line, most of us will just install a catch can, for the oil to be caught in it, to be dumped out with oil changes, isntead of the oil being burnt in the cylinders instead. Hence when doing oil changes every 5K, will have about an 1-1/2" of oil in the catch can that just get dumped out to be recycled with the other used oil at the nearest auto parts store.
Note, before changing out my old hard umbrella valve a few years back, catch can would have a lot more oil in it during oil changes isntead.
SE air intake system on a 97 RK(used a K&N filter), and instead of the vapor being dump into air filter void area, piped to installed oil catch can isntead.
Last one, with bike on jiffy stand, only fill the oil in the oil tank to the half way mark between the bottom add line, and the full line (either hot if motor oil is hot, or cold is motor oil is cold). If you fill the oil to top of stick full lines (hot for hot, cold for cold, motor will push more oil through the breathers.
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Oil from air filter 😞
