Why is there oil down the side of my bike?
#1
04-04-2013, 10:54 PM
Join Date: Nov 2010
Location: Red Banks, Mississippi
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Why is there oil down the side of my bike?
There are so many questions each week about:
Why is my bike dripping oil from the air cleaner?
Why do I have so much blow-by (or as HD calls it, oil carryover)?
Why does the side of my bike get covered with oil mist?
To start with, it is important to understand that all internal combustion engines have a certain amount of blow-by. This is because, by design, they build crankcase pressure, and that that pressure has to have a place to vent.
On modern Harley's, this happens at the head breather bolts.
Prior to the hot oily air exiting via the head breather bolts, HD has what is called an umbrella valve. Its' job is to filter out the majority of the oil and have mostly hot air vent out the breather bolts. They do a pretty good job, and when everything is right, it is mostly air and a small amount of oil that vents out the head breather bolts.
Umbrella valves can go bad, however, the majority of time that there is excess oil venting out the breather bolts it is NOT from bad umbrella valves, it is usually something else.
Below is a list of the most common reasons for excessive blow-by, and what can be done about it.
1. The single most common reason is incorrect oil level. Every owners manual has instructions on what the correct level is. There is an entire thread with all the pertinent info at this link-
https://www.hdforums.com/forum/oil-r...oil-level.html
However, here is the bottom line, straight from the HD owners manual-
"The correct oil level should register midway between the FULL and ADD marks on the dipstick.
If oil level is at or below the ADD mark, add only enough oil to bring the level to the middle of the two marks on the dipstick."
Of course, this is confusing because HD refers to the top mark as "Full" when in reality, they say in the same sentence that midway between the two marks is full. Typical. lol
Read more on this subject at the link above.
2. Old oil is losing it's viscosity, or Incorrect viscosity for temperatures you are riding in.
In the HD Owners Manual the following chart appears-
If you are riding in temps of 60* or higher, the best viscosity, which will result in the least amount of blow-by, is straight 50 weight. 20-50 may have just as good of lubrication qualities as straight 50 weight, but IT WILL produce more blow-by at temps of 60 degrees and higher.
If you are riding in temps of 80* or higher, the best viscosity is straight 60 weight. IT WILL produce LESS blow-by.
3. The bike is running too hot. The hotter the oil, the more blow-by. Modern synthetic oil starts breaking down around 300 degrees, and dino oil around 250 degrees. However, LONG before reaching those temps it gets thinner and by-passes the umbrella valves and results in more blow-by. Most will agree that the ideal oil temp is between 180-210 degrees.
4. It may not be the blow-by that is dripping oil or putting it across the side of your bike. If you have a re-useable filter, it may be over-oiled. Sometimes they come from the MFG. over-oiled, and sometimes they are over-oiled after they are cleaned.
5. Excessive lugging of the engine will produce more blow-by.
The above are all things you can address fairly easily.
Below are more serious reasons, that can require more effort to fix-
1. Engine worn creating excessive blow-by. (rings, valve seals, etc.)
2. Umbrella valves not functioning correctly.
3. Crank out of round (creating excessive crankcase pressure).
What you can do if getting excessive blow-by
Once you have made sure all the easy things are right, then if the bike is running fine and you don't want to delve into the more serious issues, there are a couple of things to do if you are still getting excessive blow-by.
1. If you have an EPA approved air cleaner that feeds the hot oily air into the air cleaner there are two choices.
A. Route it out to the atmosphere so it does not collect at the bottom of your air filter and then drip. This is also better for your engine performance and engine longevity. Gas engines run best on gasoline and cool dry air, not on gas, oil and hot air.
B. If you want to keep the EPA happy and keep routing into the air cleaner, then make sure the tubes feeding that hot oily air are well down the throat of the carb or throttle body so that it gets into the engine and not onto the air filter.
2. If you are using a traditional external breather system, then put the filter above the air cleaner, like shown in the pic below. This is so the majority of oil will drain back into the engine instead of pooling in the filter.
Alternatively you can use the Discrete Breather System to route the hose down to a filter toward the bottom of the bike... or to a "catch can" which will hold the oil and need periodic emptying.
Two examples of the many possibilities with the Discrete Breather System-
To learn more about the traditional hose/filter style breather go to this link-
http://www.dkcustomproducts.com/Comp...-ACI-EV-BR.htm
To learn more about the Discrete Breather System, go to this link-
http://www.dkcustomproducts.com/91-U...IN-EVO_c75.htm
3. If you are using Outlaw Breather Bolts, they came with extra filters. You can put those extra filters into the bolts and they will help filter out excessive oil.
To learn more about Outlaw Breather Bolts, go to this link-
http://www.dkcustomproducts.com/Poli...K-ACI-ALBB.htm
A small amount of blow-by is normal. It is NOT normal to have so much that oil is dripping or spraying the side of your bike. Even if you ride really hard for long periods at 100 degrees, the most there should be is a very light film, not enough to run or drip.
I am sure as time goes by I will remember some other things that I should have added to this post, but this is a good start, and certainly covers the most common issues.
Why is my bike dripping oil from the air cleaner?
Why do I have so much blow-by (or as HD calls it, oil carryover)?
Why does the side of my bike get covered with oil mist?
To start with, it is important to understand that all internal combustion engines have a certain amount of blow-by. This is because, by design, they build crankcase pressure, and that that pressure has to have a place to vent.
On modern Harley's, this happens at the head breather bolts.
Prior to the hot oily air exiting via the head breather bolts, HD has what is called an umbrella valve. Its' job is to filter out the majority of the oil and have mostly hot air vent out the breather bolts. They do a pretty good job, and when everything is right, it is mostly air and a small amount of oil that vents out the head breather bolts.
Umbrella valves can go bad, however, the majority of time that there is excess oil venting out the breather bolts it is NOT from bad umbrella valves, it is usually something else.
Below is a list of the most common reasons for excessive blow-by, and what can be done about it.
1. The single most common reason is incorrect oil level. Every owners manual has instructions on what the correct level is. There is an entire thread with all the pertinent info at this link-
https://www.hdforums.com/forum/oil-r...oil-level.html
However, here is the bottom line, straight from the HD owners manual-
"The correct oil level should register midway between the FULL and ADD marks on the dipstick.
If oil level is at or below the ADD mark, add only enough oil to bring the level to the middle of the two marks on the dipstick."
Of course, this is confusing because HD refers to the top mark as "Full" when in reality, they say in the same sentence that midway between the two marks is full. Typical. lol
Read more on this subject at the link above.
2. Old oil is losing it's viscosity, or Incorrect viscosity for temperatures you are riding in.
In the HD Owners Manual the following chart appears-
If you are riding in temps of 60* or higher, the best viscosity, which will result in the least amount of blow-by, is straight 50 weight. 20-50 may have just as good of lubrication qualities as straight 50 weight, but IT WILL produce more blow-by at temps of 60 degrees and higher.
If you are riding in temps of 80* or higher, the best viscosity is straight 60 weight. IT WILL produce LESS blow-by.
3. The bike is running too hot. The hotter the oil, the more blow-by. Modern synthetic oil starts breaking down around 300 degrees, and dino oil around 250 degrees. However, LONG before reaching those temps it gets thinner and by-passes the umbrella valves and results in more blow-by. Most will agree that the ideal oil temp is between 180-210 degrees.
4. It may not be the blow-by that is dripping oil or putting it across the side of your bike. If you have a re-useable filter, it may be over-oiled. Sometimes they come from the MFG. over-oiled, and sometimes they are over-oiled after they are cleaned.
5. Excessive lugging of the engine will produce more blow-by.
The above are all things you can address fairly easily.
Below are more serious reasons, that can require more effort to fix-
1. Engine worn creating excessive blow-by. (rings, valve seals, etc.)
2. Umbrella valves not functioning correctly.
3. Crank out of round (creating excessive crankcase pressure).
What you can do if getting excessive blow-by
Once you have made sure all the easy things are right, then if the bike is running fine and you don't want to delve into the more serious issues, there are a couple of things to do if you are still getting excessive blow-by.
1. If you have an EPA approved air cleaner that feeds the hot oily air into the air cleaner there are two choices.
A. Route it out to the atmosphere so it does not collect at the bottom of your air filter and then drip. This is also better for your engine performance and engine longevity. Gas engines run best on gasoline and cool dry air, not on gas, oil and hot air.
B. If you want to keep the EPA happy and keep routing into the air cleaner, then make sure the tubes feeding that hot oily air are well down the throat of the carb or throttle body so that it gets into the engine and not onto the air filter.
2. If you are using a traditional external breather system, then put the filter above the air cleaner, like shown in the pic below. This is so the majority of oil will drain back into the engine instead of pooling in the filter.
Alternatively you can use the Discrete Breather System to route the hose down to a filter toward the bottom of the bike... or to a "catch can" which will hold the oil and need periodic emptying.
Two examples of the many possibilities with the Discrete Breather System-
To learn more about the traditional hose/filter style breather go to this link-
http://www.dkcustomproducts.com/Comp...-ACI-EV-BR.htm
To learn more about the Discrete Breather System, go to this link-
http://www.dkcustomproducts.com/91-U...IN-EVO_c75.htm
3. If you are using Outlaw Breather Bolts, they came with extra filters. You can put those extra filters into the bolts and they will help filter out excessive oil.
To learn more about Outlaw Breather Bolts, go to this link-
http://www.dkcustomproducts.com/Poli...K-ACI-ALBB.htm
A small amount of blow-by is normal. It is NOT normal to have so much that oil is dripping or spraying the side of your bike. Even if you ride really hard for long periods at 100 degrees, the most there should be is a very light film, not enough to run or drip.
I am sure as time goes by I will remember some other things that I should have added to this post, but this is a good start, and certainly covers the most common issues.
Last edited by DK Custom; 01-29-2014 at 02:26 PM.
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#2
04-05-2013, 04:43 AM
Very nice explanation Kevin! The only thing I would add is...GET A SERVICE MANUAL BEFORE STARTING TO PULL VARIOUS PLUGS ON THE BOTTOM OF YOUR ENGINE...Some of the plugs are not meant to be removed to change fluids and may be tapered and if over tightened...can break your case...The correct HD manual for your bike is the best 60 bucks you will spend on it...
Ps Love my 2" tank raise on my Rocker Kevin, nice work!
Ps Love my 2" tank raise on my Rocker Kevin, nice work!
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Thor (04-09-2016)
#3
04-05-2013, 10:02 PM
Join Date: Nov 2010
Location: Red Banks, Mississippi
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Very nice explanation Kevin! The only thing I would add is...GET A SERVICE MANUAL BEFORE STARTING TO PULL VARIOUS PLUGS ON THE BOTTOM OF YOUR ENGINE...Some of the plugs are not meant to be removed to change fluids and may be tapered and if over tightened...can break your case...The correct HD manual for your bike is the best 60 bucks you will spend on it...
Ps Love my 2" tank raise on my Rocker Kevin, nice work!
Ps Love my 2" tank raise on my Rocker Kevin, nice work!
Great add...service manual is def worth the price!
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Thor (04-09-2016)
#4
05-02-2013, 07:47 PM
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Join Date: Aug 2011
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i am just starting to run into this problem myself. i ran my dyna for two seasons with the SE heavy breather. not a drip(cuz it cant). this year i swapped it out for a regular SE round cleaner. now after the bike is parked for a bit i find a pool of oil on my block between push rod blocks under the filter. now i gotta go get it tested for compression and leak down/blow by.
my ac has those crappy little rubber nipples that turn into intake. i ordered an external vent kit but am sceptical on if it wont puke oil also. i am this close to buying another SE ac with internal vent tubes in the hopes of not having more cluttered, ugly external lines.
my ac has those crappy little rubber nipples that turn into intake. i ordered an external vent kit but am sceptical on if it wont puke oil also. i am this close to buying another SE ac with internal vent tubes in the hopes of not having more cluttered, ugly external lines.
#5
05-02-2013, 07:57 PM
Very nice explanation Kevin! The only thing I would add is...GET A SERVICE MANUAL BEFORE STARTING TO PULL VARIOUS PLUGS ON THE BOTTOM OF YOUR ENGINE...Some of the plugs are not meant to be removed to change fluids and may be tapered and if over tightened...can break your case...The correct HD manual for your bike is the best 60 bucks you will spend on it...
Ps Love my 2" tank raise on my Rocker Kevin, nice work!
Ps Love my 2" tank raise on my Rocker Kevin, nice work!
I appreciate all the info from this forum but some of you guys act like your working on the space shuttle preparing to go to the moon.
#6
05-02-2013, 11:48 PM
Join Date: Nov 2010
Location: Red Banks, Mississippi
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There is a warning in the manual about it. It is the plug that you pull if you want to measure how much oil is in the pan in case you think you may be wet sumping.
One option is to let the dealership pull that one, then if it cracks the cases it is on them.
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Thor (04-09-2016)
#7
06-08-2013, 03:27 AM
There is a 4th plug in the bottom of the pan. I believe it is red loctited in at the factory. Breaking it loose has been know to crack the cases.
There is a warning in the manual about it. It is the plug that you pull if you want to measure how much oil is in the pan in case you think you may be wet sumping.
One option is to let the dealership pull that one, then if it cracks the cases it is on them.
There is a warning in the manual about it. It is the plug that you pull if you want to measure how much oil is in the pan in case you think you may be wet sumping.
One option is to let the dealership pull that one, then if it cracks the cases it is on them.
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#8
06-14-2013, 10:38 AM
Have to ask about this plug. I installed an oil temp gauge in my fairing, ran the wires and have been holding off installing the sending unit till my next oil change (which is right about now!) Am I really at risk of cracking the cases by removing this plug?? The installation kit instructions didn't seem to mention that!! I sure hate to schedule an ex$pensive dealer service just to remove this plug!!
#10
08-21-2013, 11:35 PM
Join Date: Nov 2010
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More information on the subject, directly from the Harley Manual.
"If oil is at or below the lower mark, add only enough oil to bring the level to a point between the two arrows on the dipstick."
"Refer to table 25 . Always use the proper grade of oil for the lowest expected air temperature before the next scheduled oil change."
The above 3 quotes are directly from a recent HD Service Manual. The bold is not mine, it is bold in the manual.
Table 25 shows what weight oil to run for the temperatures you are riding in.
If it is always at least 60* when you ride, you should be running straight 50 weight. NOT 20-50, straight 50 weight is what it says. The reason it says that is because MOCO knows that it will reduce oil carryover (blow-by).
If it is always at least 80*, then you should be running straight 60 weight, for the same reason listed above.
Will it hurt your engine if you run 20-50? No, although it is not recommended. HOWEVER, you should expect to get excessive blow-by because you are not running the correct weight oil for the temps you are riding in.
"If oil is at or below the lower mark, add only enough oil to bring the level to a point between the two arrows on the dipstick."
CAUTION
"Do not overfill the oil tank. Doing so can result in oil carryover to the air cleaner leading to equipment damage and/or equipment malfunction.""Refer to table 25 . Always use the proper grade of oil for the lowest expected air temperature before the next scheduled oil change."
The above 3 quotes are directly from a recent HD Service Manual. The bold is not mine, it is bold in the manual.
Table 25 shows what weight oil to run for the temperatures you are riding in.
If it is always at least 60* when you ride, you should be running straight 50 weight. NOT 20-50, straight 50 weight is what it says. The reason it says that is because MOCO knows that it will reduce oil carryover (blow-by).
If it is always at least 80*, then you should be running straight 60 weight, for the same reason listed above.
Will it hurt your engine if you run 20-50? No, although it is not recommended. HOWEVER, you should expect to get excessive blow-by because you are not running the correct weight oil for the temps you are riding in.