1971 ironhead engine oil passing through to Primary??!!
#1
10-17-2010, 12:01 AM
1971 ironhead engine oil passing through to Primary??!!
Hi Guys,
I find my 1971 ironhead is leaking under the primary.
So we check and loose the screw under it and let the oil in the primary goes out.
But after two days, it is still leaking. Then we find the engine oil is coming out as well from the same hole under the primary.
My question is, Is it normal the engine oil can pass through to the Primary?
Please help?
I find my 1971 ironhead is leaking under the primary.
So we check and loose the screw under it and let the oil in the primary goes out.
But after two days, it is still leaking. Then we find the engine oil is coming out as well from the same hole under the primary.
My question is, Is it normal the engine oil can pass through to the Primary?
Please help?
#2
10-17-2010, 03:07 AM
Outstanding HDF Member
It is normal....... sort of anyway. Let me remove your fears right away by saying you have nothing wrong.
Here is what causes this:
The Sportster uses a dry sump lubrication system..
Oil in the tank flows (by gravity) down through the oil line to the back end of the oil pump.
Inside the pump are two pairs of gears that move oil through the pump when the engine is running.
When the engine is NOT running there is a ball check with a spring located at the front of the pump (under the nipple where the oil signal light wire attaches).
This ball remains seated by nature of the spring pressure against the seat in the pump body. This spring is similar in looks to what you will find in a ball point pen.
This prevents oil draining through the pump and collecting in the crankcase lower end when the bike has been sitting without being run for a long time.
So when the engine is started up, the small oil pressure produced by the Sportster oil pump (approx 6 to 10 psi) lifts the ball off it's seat and oil is allowed to be pumped through the engine.
So the problem is your ball is not seating properly. The bike has sat for a while without being started and oil begins to drain from the tank by gravity and run through the pump gears.
When it reaches the ball check that is not properly seated the oil will enter the lower end.
The oil continues to accumulate in the lower end. Since the machine is parked on it's side stand it leans left.
In the left wall of the crankcase (inside the primary area) is something called a transfer valve. This is nothing more than a screened opening between the primary and the inside of the crankcase.
When the leaking oil gets deep enough in the case it will leak through this transfer valve and go into the primary and transmission. I have seen as much as a couple of quarts of engine oil wind up inside the transmission as a result of this.
Many people will tell you to seal up the transfer valve, using JB Weld or some such similar junk.
DO NOT DO IT!
This transfer valve is put there to relieve the air pressure created by the pistons coming down towards the lower end.
This pressure moves an oily vapor through the transfer valve into the primary case and this is vented through the small hole in the primary filler cap. Ever notice the white mesh material in that filler cap?
In 1977 the vent system was changed and the transfer valve was eliminated. But on your 1971 it has the valve and you need to leave it as it is. Also this is the reason the engine and transmission use the same grade of oil on a 1971 model.
Back to the explanation.........
Now, the way to tell this has happened to you is when you fire up the engine.
If there is excess oil in the lower end it will puke out the breather tube located under the generator and onto the garage floor. Some of the oil gets pumped back to the tank but the scavenger section of the oil pump can handle only so much and most of it gets puked out the tube.
If your machine does not puke out oil when started AND the oil level inside the tank is normal level, then the above does not apply to you.
In this case you simply have a leaking primary gasket.
But if it pukes and the oil level in the tank is down then the ball check is leaking.
The fix is to install a brand new ball and spring. Easily done by removing the sender wire from the pump, remove the nipple and then the spring and ball can be removed and replaced with new pieces.
Another way to fix this is simply crank up the engine at least once a week and run it for several minutes.
Brand new Sportsters sitting on the showroom floor will load up the base if not cranked every week or so. So it is not a real problem unless you let the oil in the tank drain out into the lower end. Then you will have horrible problems should you let that happen.
pg
Here is what causes this:
The Sportster uses a dry sump lubrication system..
Oil in the tank flows (by gravity) down through the oil line to the back end of the oil pump.
Inside the pump are two pairs of gears that move oil through the pump when the engine is running.
When the engine is NOT running there is a ball check with a spring located at the front of the pump (under the nipple where the oil signal light wire attaches).
This ball remains seated by nature of the spring pressure against the seat in the pump body. This spring is similar in looks to what you will find in a ball point pen.
This prevents oil draining through the pump and collecting in the crankcase lower end when the bike has been sitting without being run for a long time.
So when the engine is started up, the small oil pressure produced by the Sportster oil pump (approx 6 to 10 psi) lifts the ball off it's seat and oil is allowed to be pumped through the engine.
So the problem is your ball is not seating properly. The bike has sat for a while without being started and oil begins to drain from the tank by gravity and run through the pump gears.
When it reaches the ball check that is not properly seated the oil will enter the lower end.
The oil continues to accumulate in the lower end. Since the machine is parked on it's side stand it leans left.
In the left wall of the crankcase (inside the primary area) is something called a transfer valve. This is nothing more than a screened opening between the primary and the inside of the crankcase.
When the leaking oil gets deep enough in the case it will leak through this transfer valve and go into the primary and transmission. I have seen as much as a couple of quarts of engine oil wind up inside the transmission as a result of this.
Many people will tell you to seal up the transfer valve, using JB Weld or some such similar junk.
DO NOT DO IT!
This transfer valve is put there to relieve the air pressure created by the pistons coming down towards the lower end.
This pressure moves an oily vapor through the transfer valve into the primary case and this is vented through the small hole in the primary filler cap. Ever notice the white mesh material in that filler cap?
In 1977 the vent system was changed and the transfer valve was eliminated. But on your 1971 it has the valve and you need to leave it as it is. Also this is the reason the engine and transmission use the same grade of oil on a 1971 model.
Back to the explanation.........
Now, the way to tell this has happened to you is when you fire up the engine.
If there is excess oil in the lower end it will puke out the breather tube located under the generator and onto the garage floor. Some of the oil gets pumped back to the tank but the scavenger section of the oil pump can handle only so much and most of it gets puked out the tube.
If your machine does not puke out oil when started AND the oil level inside the tank is normal level, then the above does not apply to you.
In this case you simply have a leaking primary gasket.
But if it pukes and the oil level in the tank is down then the ball check is leaking.
The fix is to install a brand new ball and spring. Easily done by removing the sender wire from the pump, remove the nipple and then the spring and ball can be removed and replaced with new pieces.
Another way to fix this is simply crank up the engine at least once a week and run it for several minutes.
Brand new Sportsters sitting on the showroom floor will load up the base if not cranked every week or so. So it is not a real problem unless you let the oil in the tank drain out into the lower end. Then you will have horrible problems should you let that happen.
pg
Last edited by piniongear; 10-17-2010 at 03:10 AM. Reason: added a comment.
#3
10-20-2010, 12:49 PM
Tourer
Wow! Great explanation there pinion, I see a lot of Ironhead guys are using HD trans oil in the primary. What do you think about the mixing of that and engine oil, if it should happen.
I've been thinking about putting engine oil in the trans on my 1975 XLCH. Just got it a month ago and I know the PO was not using engine oil in the trans.
I've been thinking about putting engine oil in the trans on my 1975 XLCH. Just got it a month ago and I know the PO was not using engine oil in the trans.
#4
10-20-2010, 05:11 PM
Up to and including 1976 there is an oil transfer valve 25075-55 in the crankcase. It is actually called the oil transfer valve, but its purpose is to provide crankcase venting. Oil does pass thru it as a by product of the venting.
Because of this for those years it is recommended to use the same oil in both the engine and the primary. For 77-on we use the HD Formula+ product, or whatever we believe to be the best choice.
There is lots of controversy around this valve, some guys plugging it with JB Weld or whatever, others saying that it is necessary. I am in with the latter group.
Because of this for those years it is recommended to use the same oil in both the engine and the primary. For 77-on we use the HD Formula+ product, or whatever we believe to be the best choice.
There is lots of controversy around this valve, some guys plugging it with JB Weld or whatever, others saying that it is necessary. I am in with the latter group.
#5
10-20-2010, 05:53 PM
Outstanding HDF Member
Yep, Ironmick just said it better than I could.
Prior to 1977, when the vent system was changed and the transfer valve eliminated, the factory recommendation is to use the same oil in both primary and engine.
That is 60wt oil by the way.
The JB Weld crowd want to plug the valve and use transmission fluid, or at the minimum Harley Davidson transmission oil (fluid).
That lube is made to use after 1976, not before.
So if anyone wants to go against the factory recommendation, suit yourself.
Not me however. I use 60wt Harley oil in all compartments on my 1971 machine.
pg
Prior to 1977, when the vent system was changed and the transfer valve eliminated, the factory recommendation is to use the same oil in both primary and engine.
That is 60wt oil by the way.
The JB Weld crowd want to plug the valve and use transmission fluid, or at the minimum Harley Davidson transmission oil (fluid).
That lube is made to use after 1976, not before.
So if anyone wants to go against the factory recommendation, suit yourself.
Not me however. I use 60wt Harley oil in all compartments on my 1971 machine.
pg
#6
10-20-2010, 07:07 PM
Tourer
#7
10-22-2010, 09:18 PM
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#9
12-26-2010, 04:44 PM
Oil puking out the vent usually means that the engine has "wet sumped". This happens when it has sat idle for some time, perhaps overnight but more likely for an extended time. Oil leaks past the check ball in the oil pump and pukes out the vent when you start it up.
This condition does not necessarily indicate a problem which has to be fixed. It is common on all the old Harleys, and on some newer ones as well. However, if it happens after the bike has sat for a shorter time, such as overnight, you may need to replace the check ball. I believe this can be done with the engine in the frame. If you need to do this ask again and we can provide more info.
If you top up the tank when it has sumped then you will have too much oil in it. To avoid this never top up the oil when the engine is cold. Always let it run for a few minutes first.
Puking out the oil tank lid is another problem. That is quite unusual. I would assume that it is because there is too much oil in there. Drain out a quart or so of oil and put a catch container under the vent and run it until no more oil comes out. Then top it up to the normal level.
This condition does not necessarily indicate a problem which has to be fixed. It is common on all the old Harleys, and on some newer ones as well. However, if it happens after the bike has sat for a shorter time, such as overnight, you may need to replace the check ball. I believe this can be done with the engine in the frame. If you need to do this ask again and we can provide more info.
If you top up the tank when it has sumped then you will have too much oil in it. To avoid this never top up the oil when the engine is cold. Always let it run for a few minutes first.
Puking out the oil tank lid is another problem. That is quite unusual. I would assume that it is because there is too much oil in there. Drain out a quart or so of oil and put a catch container under the vent and run it until no more oil comes out. Then top it up to the normal level.
