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IH: Engine Mechanicals - Sub-01E

Ironhead Gearcase/Cam Cover Pics and Information


Cam Cover Fastener List

Click Here to read “Finding Acceptable Lengths for Gearcase/Cam Cover Screws” in the REF section of the Sportsterpedia.

  • 1952-1970 K/Sportster Cam Covers Use:
    • (9) Cover Screws.
      • 1/4“ x 20 x 1-1/2” Oval Slotted Head Bolt Screw (2345) x 3.
        1/4“ x 20 x 2-5/16” Oval Slotted Head Screw (2353) x 5.
        1/4“ x 20 x 2-1/4” Oval Slotted Head Screw (2352) x 1.
    • (2) Generator Mounting Bolts.
      • 5/16“ x 24 Bolt (30013-52) x 2. Angled shank under head to sit flush in mounting hole.
    • (2) Solid Dowel Pins.
      • .308” dia x .690“ long (375). Gearcase has matching dowel pin holes in front and rear.
  • 1971-1976 Sportster Cam Covers Use;
    • (8) Cover Screws.
      • 1/4” x 20 x 1-3/4“ (1971-1973 Phillips Head Screw, 1316W x 3) or (1974-1976: Posidriv Head Screw, 1316W x 3).
        1/4” x 20 x 1-1/4“ (1971-1973 Phillips Head Screw, 1317W x 1) or (1974-1976 Posidriv Head Screw, 1317W x 1)
        1/4” x 20 x 2-1/4“ (1971-1973 Phillips Head Screw, 1370W x 4) or (1974-1976 Posidriv Head Screw 1370W x 4)
    • (2)- Generator Mounting Bolts
      • 5/16” x 24 x 3-1/4“ Hex Head Bolt (30013-71) x 2.
    • (2) Solid Dowel Pins.
      • .308” dia x .690“ long (375) x 2. Gearcase has matching dowel pin holes in front and rear.
  • 1977-E1981 covers use;
    • (8) Cover Screws.
      • 1/4” x 20 x 1-3/4“ Posidriv Head Screw, (1316W) x 3.
        1/4” x 20 x 1-1/4“ Posidriv Head Screw, (1317W) x 1.
        1/4” x 20 x 2-1/2“ Posidriv Head Screw (1381) x 4.
    • (2)- Generator Mounting Bolts
      • 5/16” x 24 x 3-1/4“ Hex Head Bolt (30013-71) x 2.
    • (1) Solid Dowel Pin.
      • .308” dia x .690“ long (375). Cover has hole for rear pin but gearcase doesn't. Pin is used in front of cam cover.
  • L1981-E1984 covers use;
    • (9)- 1/4” Cover Screws.
    • (2)- Generator Mounting Bolts.
      • 5/16“ x 24 x 3-1/4” Hex Head Bolt (30013-71) x 2.
    • (1)- Solid Dowel Pin (375), .308“ dia x .690” long. Pin is used in front of cam cover.
  • L1984-E1985 covers use;
    • (9)- 1/4“ Cover Screws.
    • (2)- Oil Filter Mount Bolts
      • 5/16” x 18 x 3-1/4“ Hex Head Bolt (4392) x 2
    • (2)- Solid Dowel Pins (375), .308” dia x .690“ long.
      1 dowel pin is used in front on gearcase. 1 dowel pin is used in the right case, lower tranny area.

Cam Cover Gasket

Click Here to read more about gearcase changes around the upper feed galley.

1957-E1982 right cases with the small boss and upper oil feed oil slot:
1952-1976 K and Sportsters original gasket (25224-52), designed with an upper feed oil hole. Updated gasket (25224-52A).
1977-L1981 and some E1982 Sportsters original gasket (25224-52A) original had a single for the upper feed galley passage.
The original gasket was updated in Nov. 1979 with a short slanted slot added to match the gearcase modification in L1979-E1980 models. 1)
And the updated -52A gasket replaced the -52 gasket for 1952-1976 models in the -78B catalog.

1982-1985 and some L1981 right cases with the large boss and upper oil feed hole:
L1981-1985 Sportsters use gasket (25263-81), designed with a long horizontal slot.

1957-E1982 oil feed slot 2) L1981-1985 oil feed hole 3)
Cam Cover Gasket (25224-52A) 4) Cam Cover Gasket (25263-81)

Shifter Shaft / Brake Shaft Hole Bushings and Plugs

1952-1974 Cam Covers:
1952-1974 K models and Sportster use shifter shaft bushing (34037-52) in both the right case and the cam cover.
App. dims on bushing 34037-52) are 1/2” ID x 3/4“ long. It should be close, if not match the -75 cover bushing dims.
This bushing is open ended for the long shift shaft to run through it.

1975-1976 Cam Covers:
1975-1976 Sportsters use shifter shaft bushing (34037-52) in the right case and bushing (34037-75) in the cam cover.
As result of the Sportster going left side shift in 1975, the shifter shaft got shorter out of the right case.
The shaft end has linkages back to a crossover arm through the frame.
App. (only) dims are below for bushing (34037-75). It has one closed end which is installed on the outside of the cover.

1977-E1981 Cam Covers:
1977-E1981 cam covers came with a different bushing (25594-75) for a brake shaft.
Starting in 1977, the shifter shaft exits out the left case and the old then shifter shaft location in the cam cover became the brake shaft location.
This was the brake shaft design from 1977-1979 (even though the rear brakes went hydraulic in 1979).
However, in 1980, the MoCo moved the brake operating lever to the trans sprocket cover so the hole in the cam cover was now useless (1980-1985).
Dims:
Cam Cover Bushing Bore: .7450” 5)
Bushing OD (before installing): .752“ 6)
Bushing ID (before installing): .6250” 7)
Bushing Length: .625“ 8)

1980-E1981 Cam Covers:
In 1980, the MoCo used a rubber plug (25221-77) in the now unused brake shaft hole in the cam cover.
The brake shaft bushing was still installed presumably to allow later covers to be used on 1979 models.
The rubber plug inserts into the bushing.
The parts books (1980-1985) show the rubber plug sold for 1979-E1981 Sportsters.
As usual, that means they expected one to upgrade the 1979 system to the 1980 system.

L1981-E1984 Cam Covers:
Once again a change was made in “how to plug a hole that goes nowhere”.
There may have been some problems with the rubber plug falling out or other. The bushing and plug was deleted from the cover.
The hole was still there but threaded for metal plug (2506), 7/16”-14 x 1/2“ hex socket bolt, which screws into the cam cover.
L-1984-1985 covers did not use a plug nor did they have a hole for a plug even though the parts books show the plug for L81-85 models.

1975-1976 Sportster shifter shaft:


Internal Comparisons

You can interchange some covers if you are not concerned about the look of a stocker for your year bike (better resale trying to stay stock). 9)

Also be aware that some covers had the round cut out for the electric starter XLH that came out in 1967.
You can slap a cover on and wing it, BUT the proper way is to have the cover line reamed when the motor is apart.
(so the cam cover and the right case half are a match in tolerances.

52-78 cover had only one breather port at 6:00. 10)
79-85 had two. One at 6:00 and one at 10:00.
52-76 uses .625” pinion bushing bore.
77-85 uses .562“ pinion bushing bore.

1952-1956 Cam Cover - casting: 25202-52 11) 1957-1962 Cam Cover - casting: 25202-52A 12) 1963-1967 Cam Cover - casting: 25202-52A13)
1968-1970 Cam Cover - casting: 02-68 14) 1971-1976 Cam Cover - casting: 25202-71 15) 1977-1978 Cam Cover - casting 76-25202F 16)
1979-1980 Cam Cover - casting: 79-25202 17) 1981 Cam Cover - casting: 81-25223 18) L1984-1985 Cam Cover - casting: 25222-84A 19)
(no date code below casting)

1957-1970 Cam Covers

1957 thru 1970 Sportsters had cams designed for an ignition to be mounted on top of the cam cover. 20)
These cams are not interchangeable with post 1971 motors (what can be called the 'cone' cam cover).
Early XLs had XL cams, 1966 thru the 1970s had hotter cams known as P cams.
1970 on had the larger 1-15/16” intake valve with pistons to match (piston had a relief cut into the dome for the larger valve clearance).
Optional cams were known as PB cams, a bit more umph than P in the upper mid range.
P cams are frequently seen for sale on ebay.
When hunting for parts you want to ask, “Pre 1971 or Post 1971” for cams and covers including the sprocket cover.

1957-1962 XL/XLH/XLCH Cover

Part number (25200-57). Casting number is (25202-52A).

Click on a pic to enlarge: 21)


1963-1966 XLH, 1963-1969 XLCH Cover

Part Number (25200-63 ). Casting number is (25202-52A).

Click on a pic to enlarge: 22)


1967-1970 XLH Cover

Cover part number (25201-67). Casting number is (02-68). Top rear is cut out for the electric starter.
1967-up XLH motors all vent the oil tank air space to the cam chest at a 90° fitting on the back of the cam cover.
The previous year's vent location on the top of the rear engine case was deleted.
1969 covers had an oil tank vent fitting (62375-62).
1970 XLH cover had an oil tank fitting (62375-57).
Both fittings are 1/8“-27 NPT to 1/4” hose barb 90° elbows.

Click on a pic to enlarge: 23)



1970 XLCH Cover

Cover part number (25200-70). Casting number (02-68). TOP REAR IS NOT CUT for electric start.
1970-up XLCH motors all vent the oil tank air space to the cam chest at a 90° fitting on the back of the cam cover.
The previous year's vent location on the top of the rear engine case was deleted.
The fitting (62375-57) is a 1/8“-27 NPT to 1/4” hose barb 90° elbow.

Click on a pic to enlarge: 24)

1971-1974 Cam Covers

1971-1972, 1974 XLH Cover

Cover part number (25200-71). Casting number (71-25202).
Gasket (25224-52). Updated gasket (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (2) solid dowel pins (used at front and rear of cover).
(see full fastener list and sizes at the top of the page)
The difference in this cover from the 1973 XLH cover is this one is polished and the 1973 cover is black.

Click on a pic to enlarge: 25)


1975-1976 Cam Covers

1975-1976 XLH Cover

Cover part number (25211-75). Casting number (71-25202).
Gasket (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (2) solid dowel pins (used at front and rear of cover).
(see full fastener list and sizes at the top of the page)

Click on a pic to enlarge: 26)


1975-1976 XLCH Cover

Cover part number (25205-75). Casting number (71-25202).
Gasket (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (2) solid dowel pins (used at front and rear of cover).
(see full fastener list and sizes at the top of the page)

Click on a pic to enlarge: 27)

1977-1978 Cam Covers

1977-1978 XLH Cover

HD Part number (25201-75). Casting number (76-25202F).
Gasket: (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (1) front solid dowel pin (rear dowel hole in cover drilled but not in case).
(see full fastener list and sizes at the top of the page)

Click on a pic to enlarge: 28)


1979-E1984 Cam Covers

Starter Cutout on Top Rear

L1976-1980 Sportsters use a Prestolite starter which required a section of the top rear corner of the cam cover to be factory removed for clearance.
1981-1985 Sportsters use a Nippon Denso starter which doesn't require the cam cover clearance thus the corner is squared off (uncut).

Breather Valves

1979-E1982 production cam covers were installed with a reed type breather valve (26909-79).
In L1982, a new rubber umbrella type breather valve was used in production covers.
Breather valve kit (26909-79A) was then introduced to adapt 1979-E1982 covers with the new umbrella valve system.
So you may find used 1979-E1982 covers with the umbrella valves instead.
Click Here for more information on breather valves.
1979-1981 Sportsters use a 1-5/8“ slinger washer (31067-63).
1982-E1984 Sportsters use a 1-3/4” slinger washer (31066-82) to accommodate the larger crankcase breather valve.
L1984-1985 Sportsters don't use a generator or slinger washer.

Breather Vents

1979 is the first year a hole was drilled and tapped in top front of the cam cover for the breather vent to connect up to the air cleaner housing
The previous location on the front bottom of the cam cover for the breather tube was plugged off with a 1/8“x27 plug and the tube deleted.
A rubber hose was now piped from the top of the cam cover to the A/C (keeping the breather line from crossing the cover from the bottom).
This design was used from 1979-1990.
Some have removed the lower plug to add a second breather to atmosphere although the reviews for that mod vary.
Click Here for more information on that mod in the Sportsterpedia.

1979-1980 Ignition Changes

1979 models got a new Prestolite breakerless electronic ignition module in the cam cover nosecone.
1980 models changed to a Magnavox ignition system using different parts in the cam cover nosecone and the module was moved out of the nosecone.
This resulted in the “pocket” in the newer cover nosecone for 1980 models getting a little deeper.
Since the 1980 cover was also sold as replacement for 1979 models, the deeper pocket wouldn't work for 1979 ignitions.
So a spacer (25262-80) was included with the 1979-1980 replacement cover to extend 1979 ignitions to original location when using the newer cover.
The replacement cover part number is (25201-79A) which includes the spacer.

1979 and 1980 nosecone comparison 29) Here is the spacer from the kit. 30)

L1981 Production Changes

L1981-E1982 Gearcase/Cam Cover/Gasket Changes:
Click Here to download TSB M-841.
Cases:
L1981-E1982 engines may have one of two different types of gear case cover and crankcase set combinations.
Old style cases have a slanted slot for an upper oil feed galley to the lifters and no rear dowel pin (or bolt) to attach the cover.
New style cases have a large boss around the upper feed galley with a single hole (no slot) for a feed oil galley to the lifters.
New style cases also have an extra mounting screw hole added to the top rear corner of the cover mounting boss.
Cam Cover Gasket:
Gasket (25224-52A) originally (1977) had a single hole in the top center to transfer oil from the gasket to the upper case galley.
Along with 1979 case changes, the hole was slotted at an angle and along with L1981 case changes, the gasket was redesigned.
Old style gasket (25224-52A) can only be used with the old style covers, XLH (25227-81) and XLS (25229-81).
New style gasket (25263-81) can only be used with the new style covers, XLH (25208-81) and XLS (25209-81).
Cam Cover:
Old style cam covers can be used on new style cases along with the old style gasket.
New style cam covers cannot be used on old style cases.

1979 XLH Cover

HD Part number (25201-79 ). Casting number (79-25202F).
Gasket: (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (1) front solid dowel pin (rear dowel hole in cover drilled but not in case).
(see full fastener list and sizes at the top of the page)
Replacement cover kit (25201-79A) comes with the 1980 cover and a spacer ring (25262-80) for the ignition module.
See “1979-1980 Ignition Changes” above.

Click on a pic to enlarge:

1979 XLH cam cover 31)
1979 XLH cam cover 32) First year for top breather fitting 33)

1980 XLH Cover

Part number for cover (25208-80). Casting number (80-25222).
Gasket: (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (1) front solid dowel pin (rear dowel hole in cover drilled but not in case).
(see full fastener list and sizes at the top of the page)
This cover was also sold as a replacement cover for 1979 models with an added spacer ring for 1979 ignitions.
Part number for the replacement kit for 1979-1980 models is (25201-79A).

Click on a pic to enlarge: 34)


E1981 XLS Cover

Part number (25229-81). Casting number (81-25223). Tach drive casting still there but the hole wasn't drilled for the drive unit.
Gasket: Must use gasket (25224-52A).
Fasteners: (8) cover screws, (2) generator mounting bolts and (1) front solid dowel pin (rear dowel hole in cover drilled but not in case).
(see full fastener list and sizes at the top of the page)

Click on a pic to enlarge: 35)


L1984-1985 Cam Covers


1)
TSB M-778 dated May 13, 1980
2)
photo courtesy of Ebay seller, inlinefabrication. Link to Ebay Store
3)
photo courtesy of c3cycle.com, Link to site: https://www.c3cycle.com/
4)
photo courtesy of Ebay seller, jrsvintageharley1990. Link to Ebay Store
6) , 8)
Dims from Robison Motorcycles
12)
photo by ironheadjunkie of the XLFORUM http://xlforum.net/forums/showthread.php?t=1421916&page=2
21) , 23)
photos courtesy of Ebay seller, animalhouse2010, Link to Ebay store:
22)
photos courtesy of Ebay seller, Motorcycle Dreams. Link to Ebay Store:
25)
photos courtesy of Ebay seller, 57harleyrider. Link to Ebay Store
26) , 28) , 35)
photos courtesy of NitroFrankie Go-Fast HD, Ebay Items for Sale Page
27) , 33)
photo courtesy of Ebay seller, gnarlydavidson1. Link to Items for Sale page
29)
1979-1980 Sportster Nosecone Design Change Composite from NitroFrankie Go-Fast HD and WheatStateParts
30)
photo courtesy of Royal Motorworks Citroen Parts Plus, Link to Ebay Store
31) , 32)
photo courtesy of NitroFrankie Go-Fast HD, Ebay Items for Sale Page
34)
photos courtesy of Ebay seller, WheatStateParts. Link to Ebay Store
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