| 摘要 |
PROBLEM TO BE SOLVED: To firmly install a driving pulley onto a crankshaft. SOLUTION: In this engine, a crankshaft 10 is rotatably supported by a bearing of an engine case, while an upper end part of the crankshaft 10 projecting upward from the engine case is installed with a driving pulley 41. A belt 56 is hung between the driving pulley 41 and a driven pulley 46 of a camshaft 39. The driving pulley 41 is formed with fitting hole 41a allowing insertion of a tip part of the crankshaft 10 in a center part, while through-holes for bolts 41b are formed around the fitting hole 41a. The upper end part of the crankshaft 10 is formed with a step part 10a, while the step part 10a is formed with bolt installation holes 10e. Bolts 48 are inserted through the bolt through- holes 41b, and tip parts of the bolts 48 are screwed in the bolt installation holes 10e.
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