Clearances on 1939 Models
Model of Motorcycle
| Scout Jr. | Scout 45 | Chief 74 | Indian 4 | |
| Intake valve tappet clearance | .004 | .004 | .004 | .002 |
| Exhaust valve tappet clearance | .006 | .006 | .006 | .006 |
| Piston Clearances | ||||
| — Top land | .020 | .023 | .020 | .026 |
| — Other lands | .015 | .019 | .015 | .022 |
| — Skirt standard | .006 | .004 | .004 | .005 |
| — Skirt, Bonneville | .006 | .006 | ||
| Piston ring end clearance | .010-.020 | .010-.020 | .010-.020 | .010-.020 |
| Spark advance – Standard | 7/16″-40° | 3/8″-37° | 1/2″-36° | 5/8″-45° |
| Spark advance – Bonneville | 5/8″-45° | 5/8″-40° | ||
| Valve seat degree | 35° | 35° | 35° | 45° |
| Valve lift end play | .010 | .010 | .010 | — |
| Cam shaft end play | .006 | .006 | .006 | .002 |
| Crankshaft end play | — | — | — | .003 |
| Connecting rod side play | .015-.020 | .015-.020 | .015-.020 | .001-.002 |
| Flywheel end play-drive sprocket off | .017-.019 | .017-.019 | .017-.019 | — |
| Flywheel end play-drive sprocket on | .010-.012 | .010-.012 | .010-.012 | — |
| Transmission end play | .003-.005 | .003-.005 | .003-.005 | .014-.018 |
| Transmission countershaft gear end play | .010 | .010 | .010 | .002 |
| Bevel gear back lash | — | — | — | .005-.006 |
| Camshaft bushing clearance | .001-.0015 | .001-.0015 | .001-.0015 | .0015-.002 |
| Piston pin clearance in rod, std | .0015-.002 | .0015-.002 | .0015-.002 | .0015-.002 |
| Piston pin clearance in rod, Bonneville | .003 | .003 |
| Model 339 Standard | Inlet opens | 10° | (.060) | B.T.D.C. |
| Exhaust opens | 60° | (.795) | B.B.D.C. | |
| Model 339 Bonneville | Inlet opens | 30° | (.400) | B.T.D.C. |
| Exhaust opens | 60° | (.795) | B.B.D.C. | |
| Model 439 | Inlet opens | 12° | (.033) | B.T.D.C. |
| Inlet closes | 60° | (.650) | A.B.D.C. | |
| Exhaust opens | 60° | (.650) | B.B.D.C. | |
| Exhaust closes | 8° | (.013) | A.T.D.C. | |
| Model 539 | Inlet opens | 10° | (.037) | B.T.D.C. |
| Exhaust opens | 60° | (.625) | B.B.D.C. | |
| Model 639 Standard | Inlet opens | 10° | (.050) | B.T.D.C. |
| Exhaust opens | 60° | (.730) | B.B.D.C. | |
| Model 639 Bonneville | Inlet opens | 34° | (.359) | B.T.D.C. |
| Exhaust opens | 60° | (.730) | B.B.D.C. |
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