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* Changes were made in early 1979 production engines to improve the engagement of the clutch teeth between the mainshaft 2nd gear and the clutch gear. ¹⁾

• On September 21, 1978 starting with crank­ case (# 779-26 4- 021), the mainshaft clutch gear thrust washer thickness was decreased .020“ from .232” to .212“ (nominal). The transmission drive sprocket hub width was increased .020” to compensate for the clutch gear change. ²⁾

• This upgrade was recommended as a replacement for earlier transmissions, especially those with severe shifting service where rounding of the gear teeth is likely to occur. ³⁾
• A new drive sprocket (35205-79) must be used in conjunction with the new clutch gear, (with the new thinner thrust washer), to retain the proper drive sprocket position. Either install a new washer (35216-79) in the old clutch gear (37448-71) or use a new clutch gear (37448-79) which comes with the new washer already installed. ⁴⁾

• To convert an old clutch gear to this new one: ⁵⁾
• Remove the thrust washer and needle bearing using a puller, with a 3/4“ collet, pressing out with a rod inserted from the opposite end of gear. If you can't get your hands on the tool, these parts can also be drifted with a hammer and punch, (Caution should be used since this method can damage the bushing). ⁶⁾
• Press in new needle bearing (35961-52) and new thrust washer (35216-79). When pressing in needle bearing, press on the printed side of the bearing cage. The outer face of the bearing cage should be flush with the washer seating face (do not bottom out the bearing in the hole when pressing it in).
• After assembling sprocket on mainshaft, be sure to check mainshaft endplay with pre-load (.003” - .009“). Adjust if necessary using variable thickness mainshaft thrust washer in accordance with the FSM.

• During the 1975 season, the MoCo received several reports of XL & XLCH transmissions with a blocked oil transfer hole in the trapdoor (resulting in little to no oil supply to the transmission). So, they recommended that the dealers remove the transmission oil drain plug & measure how much oil dropped out. If less than 1.5 pints of oil ran out, the transfer hole was to be checked for blockage. This can be remedied by tapping the casting with a hammer and a punch at the hole location (1/2” hole directly below the countershaft hole). Done carefully to prevent chips from getting into the transmission, loose chips may still fall into the hole which will require flushing out the drain hole. ⁷⁾

* . . . 1957-1985 Transmission Trapdoor Pics and Information

Click on a pic to enlarge:

1977 4 Speed Transmission 15)	1977 4 Speed Trap Door 16)	1983 4 Speed 17)

1978 4 Speed transmission 18)

* . . . "The Harton Fix" - Late 84-90 clutch shell magnet fix

• Type
  • Wet - Multiple disc

• 1971-1978 ¹⁹⁾
• 8 Drive plates (37985-71), 8 Driven Plates (37992-71A), with an outer drive plate (37987-71) and retaining ring (11053).
• Back to Front : Backing Plate-F-S-F-S-F-S-F-S-F-S-F-S-F-S-F-S-Outer Drive Plate with retaining ring.
• Capacity: 1900 in-lbs (158.33 ft lbs.)
• Set up Spring Pressure
  • 1971: 234 lbs. ²⁰⁾
  • 1972: 257 lbs. ²¹⁾
• Spring adjustment
  • 1971 - 1973: 11/32 in. from outer surface of outer drive plate to outer surface of releasing disc ²²⁾
  • Late 1974 & later:
  • Clutch changes include a new pressure plate (38005-71B) and six spacers (5995) over the studs between the pressure plate and the releasing disc allowing the spring set-up pressure to be set at a controlled amount. A conversion kit (38005-71B), which contained the new pressure plate and spacers, was available to convert 71-E73 models to the new 74 style set-up. The stud holes in the clutch unlined plates (37992-71) were modified to fit loosely over six spacers. New plates have larger oblong holes and round stud holes. ²³⁾
  • Standard Spacers: (5995) - 1.530“ long. ²⁴⁾
    • Shorter spacers to increase the spring tension due to disc lining wear:
      • (5996) - 1.490” long. ²⁵⁾
      • (5997) - 1.450“ long. ²⁶⁾
        Note: The six spring tension nut adjusters (7686) and retainers (37499-71) are no longer used since the clutch spring set-up pressure is adjusted differently with this change. ²⁷⁾

• Clutch bearing: .0005 - .002 in. loose ²⁸⁾

• Periodic adjustment of the clutch is required every 2,000 miles to compensate for lining wear. ²⁹⁾
• Adjustment may also be necessary with the clutch slipping under load or dragging in the released position. ³⁰⁾

• 1979- Early 1984 ³¹⁾
• Capacity: 174 ft lbs.
• Spring Adjustment- Fixed spacers standard length 1.530 in.
  • Free Length- inner- 2-25/64 in.
    • Wear limit: 2 - 11/32 in.
  • Free Length- outer- 2-25/64 in.
    • Wear limit: 2 - 11/32 in.
• Clutch Shell Bearing on clutch gear: .0000 - .0010 in. loose
• Clutch Plate max. warp-age: .010 in.

• Late 1984-1985 ³²⁾
• Capacity:174 ft lbs.
• Spring Force (engaged): 304 lbs.
• Spring Force (dis-engaged):260 lbs.
• Clutch Shell Bearing on clutch gear: .0000 in. - .0010 in. loose

Clutch adjustment is recommended every 2,000 miles to compensate for lining wear or during clutch slippage under load, or when clutch is dragging in released position. ³³⁾

• Loosen adjuster locknut at primary case and turn adjuster inward until there is a large amount of free play at hand lever. ³⁴⁾
• Remove access plug from primary cover to view adjusting screw. ³⁵⁾
• Loosen adjusting screw lock nut and turn adjusting screw inward until it becomes harder to turn (starts to release the clutch) and continue turning (app 2 more turns) to be sure clutch is dis-engaged. ³⁶⁾
• Adjust all free play out of control cable by turning adjuster outward. Do not put any tension on cable. With all slack in cable taken out (no play at hand lever) tighten the adjuster locknut. ³⁷⁾
• Ready for final clutch release adjustment: Loosen the locknut and back off the adjusting screw until the clutch is engaged (pressure is off the screw) then turn screw inward until the point of no free play. Then turn the adjusting screw outward 1/4 - 1/2 turn to establish the correct amount of free play and tighten the lock nut. Check free play at hand lever. you should have 1/8 in. free play. If not, adjust sleeve and tighten lock nut. ³⁸⁾
• If clutch slips or drags after these adjustments, it may be necessary to inspect / adjust the clutch springs and / or clutch release mechanism for defects. ³⁹⁾

• Shifting problems after considerable mileage could be caused by a loose shifter cam assembly which results in trouble shifting the lever into various gears. It can also cause the transmission to suddenly drop out of gear.
• The shifter cam assembly is secured to the access cover with a bolt, a lockwasher and 2 dowel pins registering in the access cover. If the assembly becomes loose, the (press fitted) dowel pins can work loose from the assembly and into the access cover holes. When the dowel pins have successfully worked their way out of the assembly support, the shifter cam will tip causing a bind in the mechanism. ⁴⁰⁾

• If you’re having shifting problems and you’re sure it’s not because of a dragging clutch (before doing exploratory surgery on the internal tranny parts), try removing the chain cover and check for a loose shift assembly bolt. The bolt may appear tight, but it has been known to bottom out in the hole from being slightly too long which allows it to get tight before full clamping force on the assembly. ⁴¹⁾
• To properly tighten up the assembly, you can remove the clutch and access cover to check and make sure the dowel pins are properly press fit into the support holes and are a snug fit into the access cover. If the dowels are loose in the cover holes (slight wear), try replacing the standard dowel pins with an oversized pair (+0.001), (+0.002) or (+0.003). ⁴²⁾ If the holes are out of round in the access door, the door may have to be replaced. A good machinist could probably re-drill the holes straight to accept bigger pins also. ⁴³⁾
• When re-assembling the shifter assembly to the access cover, be sure the bolt and lockwasher secure it tight to the door. If necessary, you can shorten the bolt by 1/16” (or one thread) with a Dremil tool with a metal cutting blade or a hacksaw. If the bolt still bottoms out, the threaded hole is too shallow and the pawl carrier support may have to be replaced. ⁴⁴⁾
• Click here for pics and identification of shifter assemblies: Pics of Pawl Carriers and Pawl Carrier Supports

Clutch Sprocket Assembly

Primary Chain

• Type primary: 3/8 in. pitch triple chain ⁵³⁾
• Looseness: 5/8 to 7/8 in. slack (cold engine) - 3/8 to 5/8 in. slack (hot engine) ⁵⁴⁾

On the XLCH, the kick starter provides a means of starting the engine by manual power. When the pedal is moved in a downward stroke, ratchet teeth of the starter clutch gear and the starter clutch are engaged, transmitting force to the clutch sprocket, primary drive chain and to the engine sprocket. ⁵⁵⁾

• Minimum clearance between clutch teeth on starter clutch gear and clutch with starter in up position: .040 in. ⁵⁶⁾⁵⁷⁾
• Crankshaft endplay: .001 - .007 in. ⁵⁸⁾⁵⁹⁾
• 1979 was the last year you can outfit a Sportster with a kickstarter ⁶⁰⁾

On the XLH, an electric starter motor and Bendix type drive unit engage the ring gear on the clutch to crank the engine. ⁶¹⁾

1971-1974

• The shifter is located on the right side of the engine and is foot operated transmitting force through the gear shift shaft, actuating pawl carrier, pawls and gear shifter cam. ⁶²⁾
• The shifter cam moves shifter forks which slide a series of gear clutches on the mainshaft and countershaft into mesh with the various gears to obtain the desired ratios. ⁶³⁾

1975-1976

• To convert shifting from right side to left side, the shifter pedal was moved to the left side of the motorcycle and connected through a cross shaft linkage system to the shifter mechanism on the right side. ⁶⁴⁾

1977-1985

• The shifter shaft was redesigned again (34628-75) for 1977 and up models but still leaving it on the left side of the bike. ^{65) 66)}

1977-1985 shift lever shaft 67)

• Overall Gear Ratios are the number of engine revolutions to drive rear wheel one revolution. ⁶⁸⁾

Transmission/ Primary Oil Capacity ^{75) 76)}: 1.5 pints (24 oz) (710 ml)

• 1971 - 1978 ⁹⁹⁾
• Clutch gear ball bearing in case: .0001 - .0012 in loose
• Ball bearing on clutch gear: .0001 in. loose - .0009 in. tight
• Clutch gear on mainshaft: .001 - .002 in. loose
• Mainshaft right side roller bearing: .0006 - .0014 in. loose
• Mainshaft roller bearings: ¹⁰⁰⁾
  • (9095) Standard = .1562”
  • (9096) + .0004“ = .1566”
  • (9097) + .0008“ = .1570”
• Mainshaft end play: .003 - .009 in. with all axial play removed
• Third gear
  • On shaft: .002 - .003 in. loose
  • End play: .012 - .030 in. loose

• 1979 - Early 1984 ¹⁰¹⁾
• Clutch gear ball bearing in case: .0001 - .0012 in loose
• Ball bearing on clutch gear: .0009 in. tight
• Clutch gear on mainshaft: .001 - .002 in. loose
• Mainshaft right side roller bearing: .001 - .0034 in. loose
• Mainshaft end play:
  • No axial play (minimum)- .003 in.
  • With axial play - .020 in.
• Clearance between clutch faces:
  • Mainshaft fourth gear and second gear: .028 - .058 in.
  • Mainshaft third gear and second gear: .028 - .058 in.

• Late 1984 - 1985 ¹⁰²⁾
• Clutch gear ball bearing in case: .0001 - .0012 in loose
• Ball bearing on clutch gear: .0009 in. tight
• Clutch gear on mainshaft: .001 - .002 in. loose
• Mainshaft right side roller bearing: .001 - .0034 in. loose
• Mainshaft end play:
• Minimum - .009 in.
• Maximum - .015 in.
• Clearance between clutch faces:
• Mainshaft fourth gear and second gear: .028 - .058 in.
• Mainshaft third gear and second gear: .028 - .058 in.

• 1971 - Early 1978 ¹²⁹⁾
• Countershaft end bearings: Retained needle roller bearing
• Bearing fit on shaft ends: .0005 - .0029 in. loose
• Bearing fit in case: press fit
  • End play: .004 - .009 in.
• Second gear
  • On shaft: .001 - .0025 in. loose
• Low gear
  • On shaft: .0005 - .0016 in. loose
  • End play: .004 - .009 in. (1971-1978)
• Drive gear
  • On shaft: .0005 - .0030 in. loose
  • End play: .004 - .009 in. (1971-1978)
• Clearance between clutch faces
  • Countershaft low an third gear: .038 - .058 in.
  • Countershaft second and third gear: .038 - .058 in.
  • Mainshaft clutch gear and second gear: .043 - .083 in.
  • Mainshaft third gear and second gear: .043 - .083 in.
• Shifter end play (1971-1976): .010 - .030 in.

• 1979-Early 1984 ¹³⁰⁾
• Countershaft end bearings: Retained needle roller bearing
• Bearing fit on shaft ends: .0005 - .0030 in. loose
• Bearing fit in case: press fit
  • End play: .004 - .009 in.
• Second gear
  • On shaft: .001 - .0025 in. loose
• Low gear
  • On shaft: .0005 - .0016 in. loose
• Drive gear
  • On shaft: .0005 - .0030 in. loose
• Clearance between faces
  • Countershaft low an third gear: .028 - .058 in.
  • Countershaft second and third gear: .028 - .058 in.
• Countershaft end play: .004 - .015 in.

• Late 1984 - 1985 ¹³¹⁾
• Countershaft end bearings: Retained needle roller bearing
• Bearing fit on shaft ends: .0005 - .0030 in. loose
• Bearing fit in case: press fit
• Second gear
  • On shaft: .001 - .0025 in. loose
• Low gear
  • On shaft: .0005 - .0016 in. loose
• Drive gear
  • On shaft: .0005 - .0030 in. loose
• Clearance between faces
  • Countershaft low an third gear: .028 - .058 in.
  • Countershaft second and third gear: .028 - .058 in.
• Countershaft end play: .004 - .015 in.

• There were two different countershafts made for the Sportster 4 speed tranny. In the first picture below, the left one is used on both Ironhead and Evo models from late 1984 until 1990, ^150)151) the last year of the 4 speeds.
• The shaft to the right in the first pic shows an Andrews version of the earlier style ('58-early '84)^{152) 153)} countershaft with the oiler hole in a hollow shaft ¹⁵⁴⁾.
• Dimensions are the same on both style countershafts with exception being the shoulder for first gear which measures 0.0875 in diameter. ¹⁵⁵⁾

• The oiler plug in the trapdoor catches oil and gravity feeds it through the counter shaft to 1st gear. It will get some amount of splash lube without it, but not as good of a jet of oil as if coming from the plug. ¹⁵⁶⁾ The oiler plug sticks outside of the case 7/16”. ¹⁵⁷⁾
• Before installing the oiler plug, set it off to the side until after you've set / checked your final countershaft endplay. otherwise it'll be in your way. ¹⁵⁸⁾
• The oiler plug should be a tight interference fit. It should go in and stay in with the engine running and vibrating and carrying on. Upon dis-assembly, many are found to be loose or rather the hole has probably been worn from the aluminum being smashed in and out of a few times without heating the aluminum trapdoor to expand it. This is why you should ALWAYS heat aluminum engine and gearbox casings, wheel hubs etc, with a propane torch before removing or installing bearings. Doing it cold works once, maybe twice, then the hole is worn out. ¹⁵⁹⁾
• To fix a loose oiler plug, you can take the plug to a machine shop and get them to knurl it. That will increase the diameter by a few thousandths. Then re-install it with Loctite. I would use the red, it is the strongest. But you will then need to use a propane torch to break the Loctite to get it back out. ¹⁶⁰⁾
• You can also peen the hole to retain the oiler. ¹⁶¹⁾
• Late '84 and up trap door does not include a countershaft oiler plug. When installed in this newer trapdoor in older applications, it may easily hit and scrubb the back of the stator due to being too long. It will either need to be machined down for your clearance measurements or the old style trapdoor must be used. ¹⁶²⁾

4 Speed Trans Countershaft comparison 163)	Early style HD 4 Speed Trans Countershaft 164)	Oiler Plug in '77 tranny 165)
Oiler Plug & Countershaft Needle Roller Bearing 166)

• There are 4 different versions of oem 'pawl carriers' and 5 oem versions of the 'pawl carrier support' (shift tower).
• Here the towers are in order:

1) Used on k models167)	#2/#3/#4) next 2 pics. No pic of #3 but the text should suffice.168)

169)	#5) changed for clearence of the '77-'90 shifter shaft coming in from the left 170)

Next is the old Trock cast iron tower. By far the best shift fork control Never breaks, best of both worlds. 171)	Left '72-'76 Shift Tower (taller shaft than on the right)	Right '77-'90 Shift Tower 172)