91 flhs ignition toggle
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Alright, it runs! (For a second, the battery was dead from sitting so long and our jumper box kinda blew up lol)
However, when we start it, oil starts pouring out at the bottom of the air filter. What causes this? I know oil goes through that area, but this is a lot of oil pumping through.
However, when we start it, oil starts pouring out at the bottom of the air filter. What causes this? I know oil goes through that area, but this is a lot of oil pumping through.
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Pick a day of the week and fire up the bike for at least 5 minutes ( if you don't ride it that week that is).
What you are experiencing is called sumping.
What is basically happening is the oil is getting past the check valve and filling up the crank case.
There really isn't a fix for this other than running the motor as that will pump the oil out of the crank case, in the case of a case breather engine (like yours) it comes out the breather that for some damn reason people like to hook to the back of their air filter plates.
One option is just rout the breather to air and if you don't start bike for a while put a catch can under the breather hose,
That way all that oil doesn't get dumped all over your motor.
What you are experiencing is called sumping.
What is basically happening is the oil is getting past the check valve and filling up the crank case.
There really isn't a fix for this other than running the motor as that will pump the oil out of the crank case, in the case of a case breather engine (like yours) it comes out the breather that for some damn reason people like to hook to the back of their air filter plates.
One option is just rout the breather to air and if you don't start bike for a while put a catch can under the breather hose,
That way all that oil doesn't get dumped all over your motor.
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Joined: Aug 2018
Posts: 59
Likes: 2
From: San Antonio TX
Pick a day of the week and fire up the bike for at least 5 minutes ( if you don't ride it that week that is).
What you are experiencing is called sumping.
What is basically happening is the oil is getting past the check valve and filling up the crank case.
There really isn't a fix for this other than running the motor as that will pump the oil out of the crank case, in the case of a case breather engine (like yours) it comes out the breather that for some damn reason people like to hook to the back of their air filter plates.
One option is just rout the breather to air and if you don't start bike for a while put a catch can under the breather hose,
That way all that oil doesn't get dumped all over your motor.
What you are experiencing is called sumping.
What is basically happening is the oil is getting past the check valve and filling up the crank case.
There really isn't a fix for this other than running the motor as that will pump the oil out of the crank case, in the case of a case breather engine (like yours) it comes out the breather that for some damn reason people like to hook to the back of their air filter plates.
One option is just rout the breather to air and if you don't start bike for a while put a catch can under the breather hose,
That way all that oil doesn't get dumped all over your motor.
A friend who plays with Evos a lot recommended cleaning out that check valve, and clearing to oil out of the case. Do you think removing that valve to clean it is worth the effort right now?
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Sumping isn't something caused by age of the bike the damn things did it from new.
Now I've never done this but from what I've learned you can lap the seat with a push rod end and get a new ball and spring and that is supposed to reduce the sumping but you can't stop it entirely to the best of my knowledge.
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Joined: Aug 2018
Posts: 59
Likes: 2
From: San Antonio TX
I own a 92- if the bike has been sitting for a length of time- oil will bleed past the check ball at the oil pump- and down into the crankcase. So if you put MORE oil into the tank- it will have way too much oil in her- and therefore its gonna blow out the breathers in the head. The 91 should actually be vented at the oil pump itself (bottom breather) so someone has updated the motor or just the heads to head venting (top breather). Check to see if you have a short hose at the oil pump thats plugged.- if it has been converted- drain some oil out and try again(its still gonna make a mess- have towels ready). When its run for a bit- she'll be just fine!
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,116
Likes: 7,640
From: Poolville
First, Check to see if you still have some oil in the tank. If so just start it up. Run it a few minutes then shut it down and check the level..
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Joined: Aug 2018
Posts: 59
Likes: 2
From: San Antonio TX
There is minimal oil still in the tank, not even enough to wet the dipstick. I can see the oil using a flashlight, but if it wont even show up on the dipstick, is that enough?
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,200
Likes: 3,089
From: NW AR
If it sumped after only sitting a week, then fiddling with the check ball is probably in order. At a minimum, take it apart and clean it. If there's some oil in the tank, crank it. Sometimes, if I suspect mine is sumped, I'll start it, run it for 10-15 seconds, stop it, repeat a few times. And always with an oil catch pan under the bike. Like almost everyone else on here with a "bottom breather," my vent is routed to under the bike.
