Cycle News - Archive Issues - 1960's

',f. • " • '. Working from the bottom up , we find the Honda 450 engi ne is unusu ally compact fore and aft ; the cases spli t hor izontally , t he bottom half serving as a reservoi r t o car ry t he recommended 3 quarts of 30·weigh t oil which lubricates engine, gearbox and clutc h f rom a common source . No outside oil li nes are necessary, cont ributing to engi ne security and clean liness . While it is a wet sump system, oil drag from " windage" is nonexistent , since steel baff les above the oil level pre clude sloshing and excessive contact with the crankshaft, An oil level dipstick is fi xed to the large filler cap for posit ive inspection . The oil pump is single plunger type with it s plunger driven off a cam on the back side of the cl utch gear. Oil is pul led from the sump through a wire mesh filter, then forced through a centrifugal filter driven off th e right sid e crankshaft snout. Foreign part icles passing th rough the spinning mechanism are thrown to the out side of the canister whi ch is easily cleaned periodical ly by removi ng t he element t hrough a single cover in the primary case, a t en-minut e job. Pressurized oil leavin g the centrif ugal f ilt er provi des positive lub ricatio n t hrough interna l oi lways t o crankshaft bearings and t he camsh afts (via cylinder st ud holes) as well as the gearbo x mainshaft and even the outer clutch disc. The cam chain guide rollers and t he gearbo x countershaft are drip-fed by ind ividual splash collector sumps , while the tors ion bar valve springs survive on oil spl ash in the upper part of the head. Pump capacit y, inci dent all y, is 10 pint s per minute at 9,000 rpm ; consurnption is rated about 2 pints per 2500 miles . Since it take s a m inute and 8 second s for the oil to reach the cam sur faces when starting from cold, it is advised that engine speed be kept to 500 rpm during warm-up . The Honda 45 0 is t he only popu lar big twin I know of th at has a four main bearing lower end. The big bearings are caged rolle rs emb racing each pai r of fl ywheels (fo u r flywhee ls in all) and are held in husky indi vi dual steel pillow blo cks t hat bolt to the upper half of the crankcase. Honda eng ineers report th at by using four mai n bearings bolted to t he upper half of the case (automobile practice) bear ing effici ency is imp roved , all owing the use of t his sma ller, lighter and stronger crankshaft due to the decr ease of trict ion . Between the two cente r main bearings , midpo int on th e cra nks haft , is the sprocket whi ch drives t he chain th at runs up th rough the cent er of th e engine and around the two overhead cam shaft s. Driven and guided by sp rocket s and roll ers ( 10 in all), th is long single- row roll er chai n runs a surpris ingly stra ight path between it s t hree main sprockets; its tension is main ta ined by a spring-loaded id ler sp rocke t with an outside adjust ment set screw tha t exte nds fro m the rear base of the cylinde r casti ng. Before leaving the lower inner sanct um it should be ment ioned t hat the crankshaft is of th e built -up type with mainshafts and crankpins pres sfitted into the fl ywheels to form a complete uni t , the one-piece connecti ng rods and t heir roller bear ings being positioned on the crankpins during assem bly. Contrary to general practice, the crank t hrows are 180· apart rather than side by side as in most parallel twins. Honda act ually bu ilt prototype 450 's both ways but settled on the 180· design as best for the U.S. mark et. My calculatio n was tha t the altern ate ly wide- t hen close-spaced firing (Continued) TO P- J, .s U cutaway «h ow« in t ok » ca m, benea th 1 ic1l ifo\ ca m ('II [ oll oice r an d vu l ve s Jll'i..y [ork th n t elly n y e.• 0",1 Ioad e eolia.' 011 Ilul ve s t em, B ra ck et 0 11 oll tsicle of hea d is Hsed to p r e-loud a nd an ch or to r s ion hen' l'll h'c s p ring encl. Not e bonded ru b ber cur b .ftuJl g es, cam cha in t ell SiOne l.. A lJOF E - IAH'c tha t iunk ! E E l,O Il'- C rull ch d U W lI , uou ca ll see 105 n l 81 /00 R 's - . .. u.o t h,

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