Oil Problem on Evo
#1
#2
97's are head breathers, and HD headbreathers are good about blowing oil. You have some options. You can buy a breather kit that attaches to the heads behind the air cleaner, and leads down to a little filter you can place somewhere you dont care about oil leaks. Or, several companies make new internals for the rockers that claim to fix the issue. But since the problem is new for you, seems like the stockers were working OK for a long time. Just buy a new set of valves and seperators and you should be good to go for another 13 years.
#5
I think I've mentioned this here before, but the bit about running your oil tank a bit low to solve this issue is a myth. By design, even at the full mark, there's enough room in the oil tank for expansion and/or extra pressure. Now you definitely don't want to over fill it, but you could tow a 55-gallon drum full of oil behind your bike and the motor is only going to use the amount of oil it's designed to use.
The reason for the breather oil leaking issue is when the MOCO went to the Evo motor they finally sealed all the oil leaks of the earlier motors. Except for the blow-by oil which still dripped on the ground from the bottom end crankcase breather. In order to seal that last leak, and to comply with EPA rules (which basically won't allow motors to leak oil by design) the MOCO went to the top end head breathers where the excess oil is sucked into the carburetor and burned. The problem is the oil still seeps out when the motor isn't running and when run hard not all the oil is sucked down the carb throat. This oil also gums up the carburetor. The least worst solution is to run hoses from the head breathers down under the frame and just let it drip. If you're Green carry paper cups around with you, LOL!
The reason for the breather oil leaking issue is when the MOCO went to the Evo motor they finally sealed all the oil leaks of the earlier motors. Except for the blow-by oil which still dripped on the ground from the bottom end crankcase breather. In order to seal that last leak, and to comply with EPA rules (which basically won't allow motors to leak oil by design) the MOCO went to the top end head breathers where the excess oil is sucked into the carburetor and burned. The problem is the oil still seeps out when the motor isn't running and when run hard not all the oil is sucked down the carb throat. This oil also gums up the carburetor. The least worst solution is to run hoses from the head breathers down under the frame and just let it drip. If you're Green carry paper cups around with you, LOL!
#6
Agree...
I think I've mentioned this here before, but the bit about running your oil tank a bit low to solve this issue is a myth. By design, even at the full mark, there's enough room in the oil tank for expansion and/or extra pressure. Now you definitely don't want to over fill it, but you could tow a 55-gallon drum full of oil behind your bike and the motor is only going to use the amount of oil it's designed to use.
The reason for the breather oil leaking issue is when the MOCO went to the Evo motor they finally sealed all the oil leaks of the earlier motors. Except for the blow-by oil which still dripped on the ground from the bottom end crankcase breather. In order to seal that last leak, and to comply with EPA rules (which basically won't allow motors to leak oil by design) the MOCO went to the top end head breathers where the excess oil is sucked into the carburetor and burned. The problem is the oil still seeps out when the motor isn't running and when run hard not all the oil is sucked down the carb throat. This oil also gums up the carburetor. The least worst solution is to run hoses from the head breathers down under the frame and just let it drip. If you're Green carry paper cups around with you, LOL!
The reason for the breather oil leaking issue is when the MOCO went to the Evo motor they finally sealed all the oil leaks of the earlier motors. Except for the blow-by oil which still dripped on the ground from the bottom end crankcase breather. In order to seal that last leak, and to comply with EPA rules (which basically won't allow motors to leak oil by design) the MOCO went to the top end head breathers where the excess oil is sucked into the carburetor and burned. The problem is the oil still seeps out when the motor isn't running and when run hard not all the oil is sucked down the carb throat. This oil also gums up the carburetor. The least worst solution is to run hoses from the head breathers down under the frame and just let it drip. If you're Green carry paper cups around with you, LOL!
#7
Join Date: Nov 2008
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Agree with NickD here. My '91 FLHS has the "breather" tube running under the bike. I put a stainless steel strainer on it to keep dust/dirt out of the lower case and soaks up some of the oil. I clean it with brake cleaner and rag every oil change while it's on the bike. It rarely drips and only a few drops or so. Before I did my top end it would puke major puddles of oil after long layups occasionally. If that had gone into the old stock carb I would have been looking at major $$ to rebuild and clean it.
Hatch.
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#8
And the oil should be at a level where it touches the rubber seal on the dipstick with the bike straight up.
Good luck with that, it is way overfilled at that point, the oil level is above the oil return and vent ports inside the tank, and will blow oil out the breather like crazy.
If I run 2-3/4 quarts in the tank (oil level 1/2 inch below the filler neck) I get no oil out the breather.
Last edited by Dan89FLSTC; 01-04-2011 at 10:43 AM.
#9
John mentioned something is being overlooked - blowby, gmetorres mentioned that the problem just started and can assume he has had the bike for awhile. Getting the mist out of the intake is a good deal but might just be a extended bandaid for a problem starting but as long as it still runs ok, a little oil on the ground won't hurt anything after re-routing the breather hose.
The reason I mentoned of a possible problem is that when I slightly scuffed a piston, the air breather started dripping oil and blew back on the saddlebag, finished out the summer with a paper towel in the bottom of the filter cover and wiping the oil off when needed. Rebuilt the engine and ran the breather hose under the bike and very seldom get a drip on the ground after sealed cylinders.
The reason I mentoned of a possible problem is that when I slightly scuffed a piston, the air breather started dripping oil and blew back on the saddlebag, finished out the summer with a paper towel in the bottom of the filter cover and wiping the oil off when needed. Rebuilt the engine and ran the breather hose under the bike and very seldom get a drip on the ground after sealed cylinders.
#10
Good point, 97Bagger, probably why my oil "puking" problems went away after a fresh top end. I was burning major oil out the pipes esp. on the front cylinder.
On the topic of oil level in the tank a mechanic at a custom shop in Cardiff, Calif. told me once "as long as you can see it" in the tank. I add three qts. of oil with oil/filter change and have no problems. The level on the dipstick is about half way up the stick.
NO WAY do you fill it until it's at the "bottom of the rubber stopper". That would be almost all the way to the neck of the tank and you need at least 2" or so of "air" in the oil tank so the vent can work.
On the topic of oil level in the tank a mechanic at a custom shop in Cardiff, Calif. told me once "as long as you can see it" in the tank. I add three qts. of oil with oil/filter change and have no problems. The level on the dipstick is about half way up the stick.
NO WAY do you fill it until it's at the "bottom of the rubber stopper". That would be almost all the way to the neck of the tank and you need at least 2" or so of "air" in the oil tank so the vent can work.