Workshop Manual

Valve guides63 series 74 series75 seriesLength .......................................................... 64.5 mm (2.5394") 64.5 mm (2.5394")Inner diameter (spare part) ........................... 8.000–8.015 mm 8.000–8.015 mm(0.3150–0.3156") (0.3150–0.3156")Height above cylinder head spring plane(outer spring) ................................................ 23 mm (0.906") 19.5 mm (0.768")Clearance, valve stem – guide:Inlet ........................................................... 0.025–0.050 mm* 0.025–0.050 mm*(0.0010–0.0020")* (0.0010–0.0020")*Exhaust ..................................................... 0.050–0.080 mm** 0.038–0.064 mm**(0.0020–0.0031")** (0.0015–0.0025")*** Wear tolerance, max. 0.33 mm (0.0130").** Wear tolerance, max. 0.38 mm (0.0150").Technical DataValve springsSingle valve springsFree length ................................................... 62.8 mm (2.472") –Length, loaded 334–374 N (75–84 lbf) ......... 51 mm (2.008") –loaded 676–754 N (152–170 lbf) .... 39 mm (1.535") –fully compressed ............................. 34.8 mm (1.370") –Double valve springsOuter valve spring:Unloaded length ........................................... – 64.1 mm (2.524")Length, loaded 273–313 N (61–70 lbf) ........ – 48.6 mm (1.913")loaded 491–571 N (110–128 lbf) .... – 36 mm (1.417")fully compressed ............................. – 32 mm (1.260")Inner valve spring:Unloaded length ........................................... – 60.1 mm (2.366")Length, loaded 111–131 N (25–30 lbf) ........ – 44.6 mm (1.756")loaded 200–240 N (45–54 lbf) ........ – 32 mm (1.260")fully compressed ............................. – 28 mm (1.102")Rocker arm mechanismRocker arm bushing, diameter afterpressing in and machining ............................ 22.020–22.041 mm 25.020–25.042 mm(0.8669–0.8678") (0.9850–0.9859")15