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Foaming Oil

11K views 24 replies 15 participants last post by  Larbaldi 
#1 ·
I have an 81 Sturgis that I am having trouble with my oil foaming. I can ride about 2 or 3 miles and the pressure is fine around 32 psi after that it drops down to about 10 or 12 psi. The pressure gauge is on the rocker cover.

When I stop and look in the oil tank there is about an inch of foam on top.
I'm of course hoping someone has had this problem and found a cure. Any suggestions would be appreciated.
 
#2 ·
Try switching over to Torco 20w/50 .It has anti-foaming properties.I run it in my bike, & the bike runs cooler.I like it!!!!:clap:
 
#3 ·
Craig,
Did you consider the Torco straight 50w. Just wondering.
 
#4 ·
No Pike I didn't.When it gets cooler in nj ,& I ride i figured it would be hard starting without the muti weight oil!!! But I do like Torco alot.I read about it here on this site.I will switch to it ,in my sports bike too!!!:clap:
 
#5 ·
Hi Pikeslayer,
I did try 50W and I recently tried Redline 20W60 with the same foaming problem. I've talked to people who think it may be gas bleeding into the oil but the oil doesn't have the expected gasie smell. It reminds me of when I owned my first beater of a car and the water got into the oil causing it to foam. If I could just find where they hide the rad on harley's I could check it. Just kidding. I am stumped though.
 
#6 ·
I used to run SynIII oil like most lemmings and always noticed LOTS of foam in my tank. Now I run Torco 60w and theres no foamy stuff on top. Foam is for------>:cheers:
 
#8 · (Edited)
All oil foams. It is the nature of what they do in a machine. They get air in them. Mostly small amounts that the anti foamant deals with nicely. Excessive foam is very bad.

Motor oils have anti foam additives to deal with it. used to be silicons, not it's more exotic.

Small bubbles bump into each other and make larger bubbles, these rise. The antifoam agents exert pressure on the large bubbles, helping break the surface tension that holds them together. Pop!

That's the ideal.

Causes of excessive foaming:

Contamination, in the form of;

-Very fine particulate. Many times finer than you can see or feel. ( a current issue at my place)

-Water

- air is a contaminant. Leads to increased oxidation and loss of lubricity.

It is possible to get air introduced in a return line. Bernoullis principle will show that a low pressure area can develop and suck air in. Particularly at restrictions, bends, fittings.


Excessive agitation. There is such a thing as too much flow and pressure.

or simply, Anti foam additive depletion.

Now, fix the problem, not the symptom. You can get a thicker oil, but should you? I don't. Modern multi weight oils have very robust viscosity modifiers, So you get cold start and hot run protection. Really, unless you live somewhere where it never gets below 80, don't do straight weights.

Change the oil, check the fittings. Run a proper filter.
 
#9 ·
Hey Colonel,

Thanks for your reply regarding the foaming. I was using 50W and had foaming as do I now with the 20W60. I tried the synth oil because the supplier I had for 50w no longer carried it. The reason I would and did go with the synth oil at all was someone I respect the opinion of has recommeded it in the past, Donny Peterson. He has written books on the Harley maint. and is a regular contributer to Harley magazines. I'll include a link to his web site at HD Cylces in Canada. If you have a look at the section Tech TV in video one he mentions it but doesn't really go into detail. I would think the improvements made over the past 20 years would support the use of synth oil.
If I can get rid of the foaming while protecting my motor I'd use cooking oil.
 
#11 ·
Thank you Robert for the comments.

I will drain the oil again and see if I can get some 50W. While I'm at it I'll replace the filter. It's a bit trickier to do anything about the bends as they are minimal and there aren't any alternate method of getting to and from the tank. I should mention that I also have an oil cooler on the bike as well in case that may also have an impact. The other thing is this isnt a small amount of foam but rather about an inch deep on top of the oil in the tank. Of course this is affecting the oil pressure read at the rocker cover as well.
 
#14 ·
Cam plate?......Isn't this an 81 Sturgis?I don't recall if the Sturgis runs a belt primary.If not,are you still circulating the oil through the primary?It helped me when i sealed it off.Also,when I do an oil change,I pull the return line from the top of the tank and run the bike,with fresh oil in it,until you see clean oil coming out of the line.Some oil coolers will stir up the oil quite a bit as well.You could try bypassing the cooler too.Good luck!
 
#13 ·
Foam that affects oil pressure is excessive. Period. so you're thinking right on correcting it.

I know you can't do much about the hose and tube routing, all the same, check the connections.

And as coolmaker says, oil pump if all else fails.
 
#15 ·
This was a problem years ago with some brands of multi-grade, when all manner of additives were added. Some problems can be simply that the oil comes back into a cold tank and may get better on a long ride, where the bike and tank get really hot through.

Just try a different brand of the same grade of oil.
 
#17 ·
Some problems can be simply that the oil comes back into a cold tank and may get better on a long ride, where the bike and tank get really hot through.

Just try a different brand of the same grade of oil.
Ain't this a joke.... Hot oil in a cold tank? Don't ya' think the oil temp will climb together??? Phew...
 
#16 ·
Sorry I'm late.

Stop looking at your oil pressure gauge. Throw it in the trash. all it's gonna do is distract you when your supposed to be watching the road.

It's normal for the oil pressure on an old Shovel to drop to near zero when it's warmed up. It relies on volume instead of pressure.

Now, instead of telling you to dump a bunch of snake oil into your tank, I'll ask...

Do you run it long enough to get the oil hot enough to vaporize any moisture in the system? Water and oil don't mix well, and when you keep churning the two together without getting the oil up to about 200 degrees, you're gonna get a lot of foam. The worst thing a person can do is keep running a Shovel or Pan for short lengths of time. It never gets up to an optimal operating temperature and won't boil off the water in the oil.

Take that thing for a good, 2 or 3 hour long ride. If you still have foam in your oil after that, I'll be surprised.
 
#18 ·
Do you run it long enough to get the oil hot enough to vaporize any moisture in the system? Water and oil don't mix well, and when you keep churning the two together without getting the oil up to about 200 degrees, you're gonna get a lot of foam. The worst thing a person can do is keep running a Shovel or Pan for short lengths of time. It never gets up to an optimal operating temperature and won't boil off the water in the oil.
Whoops, if your really think the moisture is problem, I ask this. My 103 never gets above 190 degrees oil temp. Have never had any moisture problem.. Many oil changes... No foam... Ever... No erratic pressure either. ???????????????????????
 
#22 ·
Excessive foaming is caused one of two ways; 1.) mechanically i.e., plugged breather, sucking air, etc. 2.) chemically i.e., contamination, moisture, etc.

Spending a few bucks and sending both, a used AND virgin oil sample to a Lab for analysis can help you get your arms around this, rather than grasping at straws. If they can or cannot replicate foam results in either or both samples, that can and will direct you to solving the mystery.

2 key questions: When did the foaming issue start? Have you changed any internal components on the engine that come into contact with the oil (that did not before the foaming started)?

Foaming issues can be a beeyatch to deal with:thumbsdn:- although my experience is with lubricated industrial equipment rather than autos or mcy's.

Hope that helps- GOOD LUCK- YR
 
#23 ·
air

I'm in the camp that if you're trying to handle foaming with different lubricants, you're looking in the wrong direction. Thousands of these bikes run on good ole 50 or 60w with no issues. If I had to guess, I'd bet on contamination from your primary or an air/vacuum leak letting air into the system. Due to the amount of foam, I'd say on the pressure side of the pump. Check all of your fittings before gaskets. Those are easy. Also, your gauge could've vibrated apart and leaked air up at the rockers...then the rockers would froth it up for you.

Hope this helps,
 
#25 ·
I had the same situation on my 79 FXEF. I had installed an S&S stroker kit ( 88" ) along with all of the good stuff at the time ( this was 20 years ago ) ... S&S rods, S&S crank pin, S&S 495 Cam, S&S Oil Pump breather gear, opened up the breather window in the case, S&S springs, S&S retainers, Crane Roller rockers, Manley valves, S&S Super E Carb, Rowe valve guides, Ported Heads ( had a friend that worked at McLaren in Livonia ) ... I could go on and on. After lighting it up and tuning I also had a foam situation during the warm up process but after warmup it was fine. I was running 60W Valvoline Racing Oil. Don't forget that all of the bearings are roller type and this is some of the reason that the pressure falls off after warm up. Your pressure should be around 22-25 lbs rolling down the highway. If you are in that range you are fine. Don't worry about the foaming if you can maintain adequate pressure. After all ... it's a shovel .. they are damn near indestructable. Good luck Mr. Sturgis 81.
 
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