Table of Contents
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EVO: Transmission & Final Drive
1986-1990 4-Speed Constant Mesh Transmission w/Trapdoor
- The rear compartment of the left and right engine case halves form the transmission housing or case. An access cover, or trapdoor, is mounted on the left side of the case (inside) behind the primary cover. The main components of the transmission are mounted to this trapdoor to allow you to detach the one cover (together with all the transmission components) for easy removal and servicing without having to split the engine cases in half which otherwise would be a full engine re-build.
Specifications
Clutch
| 1986-1990 Wet Clutch Information 1) | ||
|---|---|---|
| Clutch plate thickness | –Friction (drive) plate (fiber) | 0.0150 in. (± 0.0031 in.) / 3.810 mm (± 0.079 mm) |
| –Steel plate (driven) plate | 0.0629 in. (± 0.0020 in.) / 1.598 mm (± 0.51 mm) | |
| Minimum Thickness (wear limit) | –Friction (fiber) plate | 0.130 in. min. / (3.302 mm) |
| –Steel plate | 0.060 in. min. / (0.0254 mm) | |
| Maximum allowable warp-age | –Friction (fiber) plate | 0.0010 in. max. / (0.0254 mm) |
| –Steel plate | 0.0010 in. max./ (0.0254 mm) | |
| Capacity | 174 ft-lbs | |
| Spring Force | Engaged: 304 lbs | Disengaged: 260 lbs |
| Clutch shell bearing on clutch gear (loose) | 0.0000 in-0.0010 in. / (0.0254 mm) | |
Primary Drive (engine to transmission)
| Year | Domestic Model(s) | Engine Sprocket | Clutch Sprocket | Ratio |
|---|---|---|---|---|
| 1986-1990 | All Models2) | 34 Teeth | 59 Teeth | 1.676:1 |
Fastener Torque Specs
- Transmission
- Mainshaft nut locking screw: 50-60 in-lbs.
- Mainshaft nut: 35-65 ft-lbs.
- Engine sprocket nut: 150-165 ft-lbs.
- Drain plug: 14-21 ft-lbs.
- Primary cover screws: 80-110 in-lbs.
- Access cover bolts: 14-19 ft-lbs.
- Stator Torx nuts: 30-40 in-lbs.
- Primary chain adjuster nut: 8-12 ft-lbs.
- Footrest nut: 24-36 ft-lbs.
- Shift lever pinch-bolt: 90-110 in-lbs.
- Neutral indicator switch: 3-5 ft-lbs.
Transmission
- Transmission/ Primary fluid capacity: 1.5 pints3)
Final Drive (transmission to rear wheel)
- Transmission sprocket - 21 teeth6)
- Rear wheel sprocket - 48 teeth
- Ratio - 2.29:1
Final Drive (Trans to Wheel)
| Final Drive Sprocket Torque (on Chain Drive Models) | |||
|---|---|---|---|
| Nut Description | Nut Size | Tightening Torque | Notes |
| 1986-90 | 1-1/8“ Nut - Right-hand Threads | 35-64 ft-lbs | Max 90ft-lbs |
| (use only 2 or 3 drops of RED threadlocker on this nut) | |||
Discussion
1986-90 Evo Sportsters: What every owner should know but were afraid to ask
An __XLForum Thread__ By Four Speed
Transmission
| Year | Overall Gear Ratios7) | Overall Gear Ratios8) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| US Models 883 | US Models 1200 | ||||||||||
| 1st | 2nd | 3rd | 4th | 5th | 1st | 2nd | 3rd | 4th | 5th | ||
| 2004 | 10.944 | 7.524 | 5.834 | 4.806 | 4.071 | 9.454 | 6.500 | 5.040 | 4.152 | 3.517 | |
| Year | Overall Gear Ratios9) | Overall Gear Ratios10) | |||||||||
| HDI Models 883 | HDI Models 1200 | ||||||||||
| 1st | 2nd | 3rd | 4th | 5th | 1st | 2nd | 3rd | 4th | 5th | ||
| 2004 | 9.792 | 6.732 | 5.220 | 4.301 | 3.643 | 9.139 | 6.283 | 4.872 | 4.014 | 3.400 | |
| Year | Overall Gear Ratios11) | Overall Gear Ratios12) | |||||||||
| Japan Models 883 | Japan Models 1200 | ||||||||||
| 1st | 2nd | 3rd | 4th | 5th | 1st | 2nd | 3rd | 4th | 5th | ||
| 2004 | 9.647 | 6.633 | 5.143 | 4.248 | 3.643 | 9.004 | 6.190 | 4.800 | 3.965 | 3.400 | |
Final Drive (Trans to Rear Wheel)
| Year | Domestic Model(s) | Transmission Sprocket | Rear Wheel Sprocket | Secondary Drive Belt | Ratio |
|---|---|---|---|---|---|
| 2004 | 883/ 883C | 28 Teeth | 68 Teeth | 136 Teeth | 2.429:1 |
| 1200/ 1200R | 29 Teeth | 68 Teeth | 137 Teeth | 2.345:1 | |
| Year | HDI / Japan Model(s) | Transmission Sprocket | Rear Wheel Sprocket | Secondary Drive Belt | Ratio |
| 2004 | 883 / 883C | 28 Teeth | 68 Teeth | 136 Teeth | 2.429:1 |
| 1200 / 1200R | 30 Teeth | 68 Teeth | 137 Teeth | 2.267:1 |
1)
1986-1990 HD HLX FSM pg 6-1
2)
1986-1990 HD Sportster FSM pg 6-1
3)
1986-1990 HD XLH FSM
4)
Number of clutch gear revolutions to drive mainshaft sprocket one revolution.
5)
, 7)
, 8)
, 9)
, 10)
, 11)
, 12)
Number of engine revolutions to drive rear wheel one revolution.
6)
1986-1990 HD HLX FSM
