Published 2008
311 Stock Engine Tech Section
General tech info on both the R16 and U20 motors:
| Item Description | SP(L)311-(R) | SP(L)311-(U) |
|---|---|---|
| Model | R16 | U20 |
| Displacement | 1,595 | 1,982 |
| Compression ratio | 9.0 | 9.5 |
| Max Power B.H.P./r.p.m.(SAE) | 96/6000 | SOLEX-150/6000 SU-135/6000 |
| Intake valve clearance(hot) | 0.0169 (in) | 0.0079 (in) |
| Exhaust valve clearance(hot) | 0.0169 (in) | 0.0118(in) |
| Ignition timing BTDC/rpm | 16/600 | Solex-20/700 SU-16/700 |
| Spark plugs | NGK B-6E | NGK B-6E |
| Spark plug gap | 0.027~0.31 in. | 0.027~0.31 in. |
| Point Gap | 0.018~0.022 in. | 0.018~0.022 in. |
| Firing order | 1-3-4-2 | 1-3-4-2 |
| Oil pan capacity US Gallon | 1.083 Gl or 4-1/3 Qts | Solex-1.875 Gl or 7.5 Qts SU-4-1/3 Qts |
| STANDARD (uncut) head thickness inches | 3.246" | 4.528-4.530" |
| Min head thickness (inch) before significant issues | -.060" | pending" |
| Standard (uncut) head thickness millimeters | 82.499 | 115.0-115.062 |
| Min head thickness (mm) before significant issues | -1.524 | pending" |
Torque Specs:
| Item Description | SP(L)311-(R) | SR(L)311-(U) |
|---|---|---|
| Cylinder head bolts 1st(ft-lbs) | 17 | 43.4 |
| Cylinder head bolts 2nd(ft-lbs) | 34 | 62.1 |
| Cylinder head bolts final(ft-lbs) | 45~50 | 65.1 |
| Connecting rod big end nuts | 35~45 | 65.1 |
| Flywheel bolts | 35~44 | 57.8 |
| Main bearing cap bolts | 71~81 | 65.1 |
| Camshaft bearing cap nuts M-8 | N/A | 13 |
| Camshaft bearing cap nuts M-6 | N/A | 5.1 |
| Cam shaft gear nut | 33~36 | 13 |
| Oil filter nuts | 15.2~19.5 | 15.2~19.5 |
| Oil pan | 3.6 | 3.6 |
| Oil pump | 11~15 | 5.8~7.2 |
| Crank pulley bolt | 145 | 144.6 |
| Jackshaft Sprocket screw | N/A | 32.5~36.2 |
| Rocker cover | 4.3~5.1 | 4.3~5.1 |