IH: Engine Mechanicals

Cam Gear Selection for Quiet Operation

  • Timing gears for 1000, 1200 and 1340 models are originally installed and are supplied through parts order in matched sets to provide the proper gear lash (tooth clearance) for quiet operation. Select gears were also made for all models (1954-1979) 1)
  • Gear Measurements:
    • Cam gears for late model 1200, 1340 and l000 engines are color coded according to their diameter size as measured with special gauge pins.
    • The gear diameter is measured with a micrometer across .105“ diameter gauge pins (95632-79) on opposite sides of the gear. The pins fit between the contacting surfaces of the gear teeth (laid longways). Gear diameter should be measured in at least 2 places and 90° apart.
  • Original gears may be different sizes, (different color codes) to produce a properly matched set at the factory in any one engine while parts order matched gear sets are of one color. These were not happy-go-lucky dimensions.
  • Replacing worn gears:
    • Although all gears in the same engine (from the factory) are matched for proper fit, instances may occur where gears become worn and (excessive tooth clearance) produce a rattling noise particularly noticeable at the gear case cover at low RPMs. In such cases, a larger gear size can be selected to reduce the tooth clearances between the mating gears for quieter operation.
  • Procedure:
    • In 1000cc engines with 4 matched cam gears, it is recommended to increase the size of gears 1 and 3 by one color code (but no more than two size increases should be made before also increasing the pinion and intermediate gears). Then, run the engine to check for noise. However, if a gear whine or howl is produced by a size increase, it indicates that there is not enough tooth clearance and the size of the affected gears must be reduced.
    • With gear noises, in general, an increase in gear size will reduce rattle while a decrease in gear size will reduce gear whine or howl.
    • It is possible that gear whine or howl may be present to some extent in a new engine and may not disappear during break-in. A mild whine is acceptable, but if excessive, the gear train can be “fine-tuned” by using smaller size gears as described before.
  • An Alternative Method of Gear Selection requires removal of the push rods, tappet blocks and spark plugs. Check for gear tooth tightness by moving gear back and forth with a screwdriver and noting the resistance to movement. Do this for several positions (rotate flywheels). On the average, there should be a slight drag. The gear should not be too tight at any one spot which would indicate that the gear is out of round.
  • Color coding system:
    • Different gear (including cams, pinion, intermediate and generator drive gear) diameters were cut to a specific dimension with a base dim and an oversized dim for each color (0.001” apart). The base dim of the next color up was the same as the oversized dim for the previous color.
    • Some gears were cut to a standard dimension while specific gears were duplicated in multiple dimensions as the chart below shows. These specific gears were selected for different year models and design went all the way back to 1954 K models. Each Sportster year model selected had a color code starting with brown and ending with black:
Gear Dimension Changes by Color Code
Brown → Black denotes ranges starting with the smallest and increasing in size to largest dimension.
BrownBlueRedWhiteGreenYellowBlack
.000 - .001.001 - .002.002 - .003.003 - .004.004 - .005.005 - .006.006 - .007
Brown ← Black denotes ranges starting with the largest and decreasing in size to smallest dimension.
BrownBlueRedWhiteGreenYellowBlack
.000 - .001.001 - .002.002 - .003.003 - .004.004 - .005.005 - .006.006 - .007
Gears Manufactured with Multiple Dimensions including Ranges
19541985
Pinion54-76 (24011-37)Range Brown ← Black - 1.2681-1.2611
77 (24015-74)
78-85 (seven part #s-74)
(Standard 24059-74 - Green 1.2641-1.2631) 2)
Replacement for 77 models
Range Brown ← Black - 1.2681-1.2611
19571979
Idler(25576-57)Range Brown ← Black 3.0223-3.0153
19591979
Rear Exhaust(25504-59)Range Brown → Black 1.8893-1.8963
Front Intake(25501-59)Range Brown → Black 1.8893-1.8963
19711979
Rear Intake Inner(25485-71)Range Brown ← Black 1.8953-1.8883
Rear Intake OuterRange Brown → Black 2.3902-2.3972
Front Exhaust Inner(25503-71)Range Brown ← Black 1.8953-1.8883
Front Exhaust OuterRange Brown → Black 2.3902-2.3972
1980 → 1985 3)
Front Intake(seven part #s-80)Range Brown → Black 1.8893-1.8963
Rear Exhaust(seven part #s-80)Range Brown → Black 1.8893-1.8963
Late 1984-1985 4)
Front Exhaust(seven part #s-84)Range Brown - Black

Removing Cams

  • Slow and steady as she goes. That mind set will be very helpful in keeping problems to an absolute minimum. 5)
  1. Get a good helper
  2. Get a magnet on a stick ( and pray you won't need to use it).
  3. Pull the gen idler out.
  4. Hold cams in place so they stay put in the torrington case.
  5. Have your helper lean the bike over to the right while you hold the cams in.
  6. Remove #4 (front exhaust) cam.
    If the rollers fall out of the worn torrington, they will now fall into the cam cavity (not into the crankcase).
    • If this happens, use the magnet to pull the remaining rollers from the torrington before you stand bike back up.
    • Then, stand the bike back up with the 3 other cams still in place.
    • Pick the rollers out of the cam chest, count them and set them aside as a set.
  7. Shove a paper towel in center of the oil pump breather gear before removing the #2 (rear intake) cam and repeat steps 1 thru 6.
  8. To remove #3 cam (front intake), repeat 1 thru 6 again.
  9. To remove #1 cam (rear exhaust), repeat 1 thru 6 again.

Gearcase Cover

68 Gearcsae Cover 6)

Cam Bearings

78 Cam Bearings 7)

Camshaft Timing

There is no relationship between the timing of the cams and the position of the crankshaft timing mark in the hole. Just line up the cam marks and the pinion gear mark and you are done. 8)

Installing Cams

Use some clothes pins to hold the lifters out of the way 9)
Start with the pinion gear in around this position → 10)CAM 1 → 11)CAM 2 → 12)
CAM 3 → 13)CAM 4 → 14)All done. ✔15)

Installing the Pinion Gear

  • From the 79 to 85 FM, there is a timing mark on the pinion shaft and a timing mark on the pinion gear. These must line up. 16)
Pinion Shaft Timing Mark 17)

Camshaft Shims

  • Camshaft shims (6769 & 6770), used to control maximum camshaft end play were discontinued in 1982 production engines. It was determined through engineering testing that an increase in the maximum allowable cam gear shaft end play does not contribute to an increase in noise or prove to be detrimental to component operation. 18)
  • When reassembling engines after service or repair, it isn't necessary to re-install the camshaft shims. The cam gear shaft end play should be measured following the procedure in your FSM. Observe the minimum end play specs of 0.005“ for all cam gears, except rear intake which is 0.004” min. end play. It is no longer necessary to measure maximum cam gear shaft end play. 19)

Gearcase Cover

Sub-Documents

* . . . Gearcase Cover Removal

  • Caution: Improperly intermixing components can cause loss of top­ end oil pressure and subsequent damage. After replacing any of these components, check top-end oil circulation to ensure proper operation.
  • Late 1981 and Early 1982 engines may have one of two dif­ferent types of gear case cover and crankcase set combinations. 20)
    • The early style cover, of course, was designed for use with the early style crankcase using the required early style gasket. But, it will also fit the late style crankcase while using the early style gasket.
    • The late style cover will not work with the early style crankcase and the late style gasket must be used with it.
    1. Old crankcase has a small boss with an oil trough (top center) on the cover mounting flange.
    2. New crankcase has a larger boss with an oil hole (top center) and an extra threaded mounting hole (top left) in the flange.
    3. Old style gasket (25224-52A) has a short slot (top center) at the oil hole location.
    4. New style gasket (25263-81) has a long slot (top center) at the oil hole location.
    5. Old style gearcase covers (XLH 25227-81) and (XLS 25229-81) have a rubber plug on the lower left.
    6. New style gearcase covers (XLH 25208-81) and (XLS 25209-81) replaced the rubber plug with a hex capscrew and also contains the extra mounting hole (top left).

Pinion Gear

Compatibility

Part#Year Models
24011-371954-1976 KH / XL / XLH / XLCH
24059-741977-1978 XLH / XLCH
24055-74 (brown)1979-1985 XL / XLCH / XLS / XLX
24056-74 (blue)
24057-74 (Red)
24058-74 (white)
24059-74 (green)
24060-74 (yellow)
24061-74 (black)

Tappets (Lifters)

  • Reports were received indicating that tumbling stone contamination may have been existent in Late 1982 - Early 1983 engines with crankcase VINs (782025001-783200001). Tumbling stones are used in the polishing process of tappet bodies and occasionally can become wedged within the tappet body. The retention of a tumbling stone in the tappet assembly will cause premature tappet wear. If contamination has occurred and tumbling stone material is allowed to circulate through the engine for an extended period of time, some engine damage will eventually occur. Affected engines will first show excessive wear of one tappet guide assembly. 21)


1)
HD Service Bulletin #M-743 dated April 3, 1979
2)
HD Service Bulletin #M-830A dated June 30,1981
3) , 4)
1979-1985 HD Sportster Parts Catalog pg 19
6)
photo by Bobeaser of the XLFORUM http://xlforum.net/forums/showthread.php?t=563241
18) , 19)
HD Service Bulletin #M860 dated November 12, 1982 pg 1
20)
HD Service Bulletin #M-841 dated October 16, 1981
21)
HD Service Bulletin #M-857 dated October 5, 1982
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