Oil sludge question
Road Warrior
Joined: Aug 2007
Posts: 1,979
Likes: 4
From: Central IL
Sludge can become a serious problem if it is allowed to become so bad that it obstructs the scavenge ports. These are what allow oil to drain from the top end back down to the crankcase. In extreme cases it can actually "starve" the bottom end of oil, especially if the oil level is low to begin with. More frequent oil changes will help but not totally eliminate the problem. Older vehicles that have been subject to many short trips without the engine getting up to operating temperature will have more problems. This is why you should be a bit leary when the used car salesman tells you that the 10 year old used car you are looking at with only 20K miles was "Only used by a little old lady to drive to the grocery store and to church on Sunday."
Club Member
Joined: May 2007
Posts: 145,895
Likes: 821
From: 40 miles Northeast of Indy..
Ive been told it take 10 minutes or 10 miles to warm up motor through out...
oils today are better than those 30+yrs ago.
I believe the paraffin used in the oils back then caused problems in short run engines
oils today are better than those 30+yrs ago.
I believe the paraffin used in the oils back then caused problems in short run engines
Tourer
Joined: Jun 2009
Posts: 302
Likes: 8
From: Huddersfield. U.K.
Road Master
Joined: Jan 2008
Posts: 874
Likes: 2
From: Southern Arizona
Another problem that hasn't been nmentioned is fuel in the oil. If the bike isn't ridden enough to burn off unburned fuel that has managed to make it into the oil, you will notice the oil will begin to have a very gassy smell. That's what happens when someone starts the bike in the driveway once a week/month and then just puts it away again. My son used to ride his Sportster to school about 2 miles away and we constantly had that problem. When he began to have to ride across town his first year of college, the problem went away.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,590
Likes: 6,435
From: Honah Lee
Same thought as NoBoldRider
Since a air cooled Harley is without any type of thermostat or fan it has a wide operating temperature? I think it's more of an average span which can be pretty big although average riding at an average temperature will give rather constant results for each individual. I just got back from a 5 mile trip at around 35mph. Its 93 outside. Took about 16 minutes. I had 150. My trip to work at 10 miles with last 6 miles being at 55-65 will get 205 at 97 degrees. I've seen it at 140 for the same work trip at 35 degrees. To get back to the water problem I would like to add that I would be more concerned with your fuel ratio if you have a modified carb or a aftermarket adjuster on a FI. Need to watch your plugs closely. When it comes to a Harley too much fuel will do more harm then a moisture problem. Of coarse with that said too lean will also hurt. Once you start modifying the exhaust and intake you really need to know what you are doing and either have the proper equipment to read the exhaust gases or really watch the plugs.
Cruiser
Joined: Dec 2007
Posts: 173
Likes: 0
From: W.V.
oil temps
This all seems a little odd talking about HD engines not getting hot enough.
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Road Master
Joined: Feb 2010
Posts: 1,210
Likes: 1
From: LI, NY
Condisation is a normal part of internal combustion engine operation. Engineers are aware of this when they design engines and oil.
Engine combustion produces water.
You put the following chemicals into a cylinder: HC, O, S, N. Then ignite them.
Now if oil had no traces of S then there would be no acid rain, air contains N so there will always be NOx.
However when the HC is burned the O and the H combine after the burn and form H2O. What we see out the tail pipe when an engine is cold is water vapor/condesation. As the engine gets warmer we no longer see the water vapor come out of the tail pipe. However the engine combustion process is still producing water, and will until the engine is shut down. We don't see this water on a warmed up engine because the engine and exhaust system is now hot enough to completely vaporize the water into droplets too small to be seen by the naked eye.
Exhaust gases are also what gets past the rings and into the crankcase. This is how water vapor gets into the crankcase. As long as the engine runs water vapor will be created an enter the crankcase.
This is why engines need crank case breathers to get all vapors out of the crankcase.
The C and O combine and form CO and CO2 however if combustion was 100% efficient there would be no CO just CO2.
So out of our tail pipes would come carbonated water, CO2 H2O, San Pellegrino or Perrier.
White sludge on underside of oil cap is no big deal. Wipe clean if it bothers you. You can always shorten oil change periods to adapt to cold weather.
Condesation on the underside of an oil cap during the warm months with a water cooled engine is a red flag that coolant is getting into the oil.
Engine combustion produces water.
You put the following chemicals into a cylinder: HC, O, S, N. Then ignite them.
Now if oil had no traces of S then there would be no acid rain, air contains N so there will always be NOx.
However when the HC is burned the O and the H combine after the burn and form H2O. What we see out the tail pipe when an engine is cold is water vapor/condesation. As the engine gets warmer we no longer see the water vapor come out of the tail pipe. However the engine combustion process is still producing water, and will until the engine is shut down. We don't see this water on a warmed up engine because the engine and exhaust system is now hot enough to completely vaporize the water into droplets too small to be seen by the naked eye.
Exhaust gases are also what gets past the rings and into the crankcase. This is how water vapor gets into the crankcase. As long as the engine runs water vapor will be created an enter the crankcase.
This is why engines need crank case breathers to get all vapors out of the crankcase.
The C and O combine and form CO and CO2 however if combustion was 100% efficient there would be no CO just CO2.
So out of our tail pipes would come carbonated water, CO2 H2O, San Pellegrino or Perrier.
White sludge on underside of oil cap is no big deal. Wipe clean if it bothers you. You can always shorten oil change periods to adapt to cold weather.
Condesation on the underside of an oil cap during the warm months with a water cooled engine is a red flag that coolant is getting into the oil.