• 04 Style Oil Cap Repair (fix for symptoms of the cap popping out of the tank).
  
• 07 Style Oil Cap with Homemade Temperature Gauge

97-03 Oil Cap 1)

97-03 Oil Cap 2)

The hole in the tank for the oil cap is tapered.
The top of the taper is app. 1.274“ and the bottom of the taper is app. 1.224”.

97-03 Oil Cap Hole in Tank Dims 3)

These can be stubborn to turn all the way. ⁴⁾
You can use a little silicone lube on the O-ring to help it turn without binding.
Also a leather glove for grip helps.
The threading tabs in the tank is molded in.

When installing the cap, it may stop at the first “bite” and not go any farther.
The plastic cap has a void underneath which gives no support.
If the cap is difficult to turn in, it may have been inserted in the wrong position.
First, try to remove it and make sure the tab orientation is correct before re-inserting it in the tank.
(else it won't turn all the way 'home' and seal off the tank).

The metal cap with the analog gauge moves better as it is solid underneath the rim.

The pics below show the positions of the cap during installation.:

This shows the broader of the 2 locating pegs in the oil tank. 5)	This shows where the gauge is to start with. 6)

This shows the point of “first bite”. 7)	This shows final location. 8)

Tank Assembly per Year Model: ^{9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28) 29) 30) 31) 32) 33) 34) 35) 36) 37) 38) 39) 40)}

In 2004, the MoCo started using plastic oil tanks. There were two factory installed versions, 04-06 (62888-04 ) and 07-09 (62888-04A).
The 04-09 oil tank versions share the same basic setups as the oil tank and electrical junction box (that is vulnerable to moisture). ⁴³⁾
The EFI bikes use up more space in the junction box, having an additional relay and more fuses?).

Late 2009, they came out with an upgrade version (62888-04B) with a 10 PSI pressure relief valve in the top of the tank, right side.
The -04B tank fits 2004-2009 Sportsters and also has a less restrictive vent tube configuration inside the tank.

04-09 Oil Tank Upgrade (62888-04B) 44)

In 2010 they revised the oil tank again (62954-10), AND the electrical junction block (to better protect it from moisture).
They also moved the ECM from under the seat to behind the rear jug.
A 10 psi pressure relief valve was installed in the top of the tank. ⁴⁵⁾
If the vent line / vent tube is pinched or restricted, tank overfilled etc., excessive pressure is created in the oil tank.
The valve opens if the pressure in the tank exceeds 10 psi to prevent damage to the oil tank.
The oil return line was also relocated to right hand side of XL models due to the ECM relocation.
It could also be speculated that the return line was relocated to place it farther away from the tank vent line.

2010-2013 Oil Tank (62954-10). (All models except XR1200/XR1200X) 46)

2010-2013 Oil Tank Cover. 47)

See the full article, Oil Tank Pressure, in the REF section of the Sportsterpedia.
There should not be any noticeable pressure in the oil tank.

During normal operation;
With the tank cap / dipstick removed, tank pressure is vented to atmosphere from the top of the tank.
With the tank cap / dipstick installed, tank pressure is vented to the cam chest via a hose connecting the two.

During shutdown;
The oil tank vent is connected to the cam chest and the cam chest is vented out the breather valve(s) in the cam cover or heads, respectively.
So if you have pressure in your oil tank and the vent to the cam chest is not blocked then the cam chest is also pressurized.
If the cam chest is holding pressure, then your breather valve(s) can not be venting properly.

Bottom line is that if the vent system is working properly, you shouldn't have excessive pressure build up in the oil tank. ⁴⁸⁾

Be careful of the feed line on 94-03 models as the FSM diagram is mis-leading. ⁴⁹⁾
Feed comes off the oil pump, under the engine, tees to the drain and up to tank.
The oil pump scavenger (return) is on the top of the oil pump at the front fitting.
On the tank, the feed is the big nipple (1/2“) on the back side. ⁵⁰⁾
The return and vent lines are on the side of the tank facing the front of the bike.

Oil hose sizes: ⁵¹⁾
Feed hose: 1/2 ” at tank but changes to 3/8“ prior to pump.
Return hose: 3/8” from pump to tank.
Vent hose: 1/4“ from cam chest fitting to tank.

In the pics below; ⁵²⁾

• A is the drain
• B is the feed
• C is the vent
• D is the return

94-03 Oil Tank Fittings 53)	2004-2009 Oil Tank Fittings 54)

2010-2013 Oil Tank Fittings (All except XR1200X / XR1200R) 55)	2014 and Up Oil Tank Fittings 56)

Fittings are labeled in the pics below.

86-90 oil pump fittings labeled. 57)	91 and Up oil pump fittings labeled 58)

Periodically inspect all your oil hose connections for leaks or cracks / deteriation, especially before long rides.

⁶⁰⁾

There is a dedicated drain hose from the oil tank.
It comes out from the tank, makes a 90 degree bend to the rear and fits into a cylindrical plug welded to the underside of the battery tray.
(on the rear part of the tray, near where the batter strap is fastened) ⁶¹⁾
You should see the oil feed fitting on the bottom of the tank from the chain guard side.
The drain fitting is at the bottom of the sheet metal that forms the back of the tank.

Engine oil drain hose location on a 1989 XLH 1200 62)

There is a tee in the feed hose (near the frame on the left side of the bike) and the drain hose comes off that tee.
There is a steel plug welded to the rear of the frame under the swingarm.
The drain hose fits over that plug with a worm clamp to hold it there.

Oil feed and drain hose 63)	Engine oil drain hose location on a 1998 1200S 64)

• 04-05 Oil Drain Plug Mods

There is a plastic clamp (33123-04) from the bottom frame rail that has a hollow stud for the oil tank drain hose to clamp onto.
The drain hose is anchored up inside the lower rails.

Drain clamp on 04-05 models 65)		Wider view 66)

The MoCo eliminated the clamp itself and went to a solid plastic plug (33123-06). ⁶⁷⁾
It has a small head that hose clamps into the drain hose and dangles between the bottom frame rails.
It just barely peeks below the frame rails. You can cut the hose a little shorter so it doesn't hang too far below the rails ⁶⁸⁾

Drain plug location on an 06 883 69)

The plastic plug was updated (33123-06A).

09-up oil tank drain plug 70)