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23-659: Despite their large capacity, this motor was not equipped with balance shafts . When used in the passenger cars both versions of the KA24 used a crankshaft girdle, as opposed to individual main bearing caps. In the Nissan Hardbody and Frontier applications a crank girdle was not used. The KA20DE was a DOHC 16-valve engine produced from June 1999 through August 2007. It was mainly used in Japanese Domestic Market commercial vehicles. The KA24E

46-458: A 270° crankshaft results in a smoother engine. Stuart Wood, Triumph's chief engineer, said that a 270° crank was ideal for large-capacity parallel twins, as it "generates fewer of those irritating high frequency secondary vibrations". Since the TRX's demise, the 270° concept has emerged as a successful compromise for standard and cruiser motorcycles. Because of its "parts bin" heritage, some of

69-401: A V-twin, and they'll never have the exotic feel of a triple...". the parallel-twin layout is having something of a revival: the latest Honda Africa Twin is a 270° parallel-twin rather than the earlier V-twin incarnation; and the best-selling Royal Enfield Interceptor 650 has a 270° crank. Although the 270° crank concept has been attributed to Vincent Motorcycles ' Phil Irving , the TRX

92-479: A larger stroke increases the difference in acceleration and a larger bore increases the mass of the pistons. The Lanchester design of balance shaft systems was refined with the Mitsubishi Astron 80 , an inline-four car engine introduced in 1975. This engine was the first to locate one balance shaft higher than the other, to counteract the second order rolling couple (i.e. about the crankshaft axis) due to

115-464: A solo rider, there is meagre provision for a pillion passenger. The TRX engine was derived from that in the Yamaha TDM850 , but the TRX is lighter, lower and sportier than its TDM stablemate. The engine has five valves per cylinder , three inlet and two exhaust; the inlets are 26   mm, exhausts 28   mm. Unusually for a dry sump design, the oil tank is not remote, but is integral to

138-530: Is a sports motorcycle with a 10-valve DOHC 849 cc 270° parallel-twin engine. First released in Japan in 1995, a version for the European market was available from 1996 to 2000. The TRX has a half fairing , clip-on handlebars and mildly rear-set footrests. The front forks are conventional telescopics, and the rear suspension is a rising-rate monoshock unit. Effectively a factory-built café racer for

161-425: Is most commonly used in inline-four and V6 engines used in automobiles and motorcycles. The operating principle of a balance shaft system is that two shafts carrying identical eccentric weights rotate in opposite directions at twice the engine speed. The phasing of the shafts is such that the centrifugal forces produced by the weights cancel the vertical second-order forces (at twice the engine RPM ) produced by

184-581: Is not symmetrical throughout the crankshaft rotation; thus during a given period of crankshaft rotation, the descending and ascending pistons are not always completely opposed in their acceleration, giving rise to a net vertical force twice in each revolution (which increases quadratically with RPM). The amount of vibration also increases with engine displacement, resulting in balance shafts often being used in inline-four engines with displacements of 2.2 L (134 cu in) or more. Both an increased stroke or bore cause an increased secondary vibration;

207-480: The BMW GS parallel-twin , is to use a 'dummy' connecting rod which moves a hinged counterweight. Balance shafts are often used in inline-four engines , to reduce the second-order vibration (a vertical force oscillating at twice the engine RPM ) that is inherent in the design of a typical inline-four engine. This vibration is generated because the movement of the connecting rods in an even-firing inline-four engine

230-537: The Japanese DE. They retained the knock sensor and piston oilers. KA24DE KA24DE-A [1] Balance shaft Balance shafts are used in piston engines to reduce vibration by cancelling out unbalanced dynamic forces. The counter balance shafts have eccentric weights and rotate in opposite direction to each other, which generates a net vertical force. The balance shaft was invented and patented by British engineer Frederick W. Lanchester in 1907. It

253-569: The KA24DE has a higher redline than the KA24E. KA24DE-A is an Altima specific model of the KA24DE. The head and block are non-interchangeable between all other models and are uniquely cast for front wheel drive operation. Differences in the Japanese block to Mexican are also present. The Mexico blocks (all DEs except those found in the S series) implemented a distributor and oil pump drive similar to

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276-462: The L series; from the crank nose. They also used a single row chain for the upper timing assembly without valve cover mounted guide. In addition to this, they removed the rearmost cam journal in the Mexico head. The crank rides on individually capped bearings with a slightly smaller diameter than the Japanese block, with shorter, slightly lower compression pistons in cylinders that have thicker walls than

299-506: The TRX, while the TDM series, enlarged to 900   cc, remained in production until 2011. The TRX was designed to compete in the market with the Ducati 900SS V-twin, whose tubular trellis frame it mimicked. Although developed cheaply from Yamaha's "parts bin", using a TDM850 engine, the TRX performs well and has "a coherent identity of its own". In Motorcycle News ( MCN ) said the TRX

322-545: The V-angle. Any inline engine with an odd number of cylinders has a primary imbalance , which causes an end-to-end rocking motion. As each cylinder bank in a V6 has three cylinders, each cylinder bank experiences this motion. Balance shaft(s) are used on various V6 engines to reduce this rocking motion. Examples are the Mercedes-Benz OM629 and Volvo B8444S engine. Yamaha TRX850 The Yamaha TRX850

345-428: The dual cam engine include the use of a knock sensor, larger diameter girdled main bearings in the Japanese block, different oil pan (not interchangeable between Japanese and Mexican blocks), different oil pickup (front pickup on Japanese block and side on Mexican block), dipstick location (toward the rear of block on Mexican and mid block on Japanese) and piston oil squirters. In addition to the increased power and torque,

368-471: The engine, sitting atop the gearbox. This simplifies manufacture, avoids external oil lines, and gives faster oil warm-up. The shallow sump allows the engine to be sited lower, for an optimal CG position. The 360° crankshaft of the original TDM was changed to a 270° crankshaft in 1996, after which time the TRX and the TDM shared the same engine and transmission. The engine has a balance shaft to smooth out residual vibrations. In 2000 Yamaha stopped making

391-508: The engine. The horizontal forces produced by the balance shafts are equal and opposite, and so cancel each other. The balance shafts do not reduce the vibrations experienced by the crankshaft . Numerous motorcycle engines— particularly parallel-twin engines — have employed balance shaft systems, for example the Yamaha TRX850 and Yamaha TDM850 engines have a 270° crankshaft with a balance shaft. An alternative approach, as used by

414-603: The exceptions of the 240SX, 1994-97 Altima (re-badged Bluebird SSS), and the U13 Bluebird released in Australia with FWD configuration, which were manufactured in Yokohama, Kanagawa , Japan . The KA24DE is very similar to the KA24E. The KA24E is SOHC with three valves per cylinder actuated by rocker arms , and the KA24DE is DOHC with 4 valves per cylinder and shim-over-bucket valve actuation. Design improvements of

437-523: The parallel-twin format for high-performance sportbikes, (such as the 2004–2007 MZ 1000S and the Métisse Mk5 ), MCN reported that parallel twins were attracting fewer buyers. Compared to V-twins, parallel twins have fewer components and cost less to manufacture, driving a renewed interest, especially 270° crankshaft twins. Although Visor Down was doubtful, saying, "They're never going to be as popular as inline-fours, they'll never be as iconic as

460-530: The torque exerted by the inertia caused by increases and decreases in engine speed. In a flat-four engine , the forces are cancelled out by the pistons moving in opposite directions. Therefore balance shafts are not needed in flat-four engines. Balance shafts are also used in straight-five engines such as GM Vortec 3700 . In a straight-six engine and flat-six engine , the rocking forces are naturally balanced out, therefore balance shafts are not required. V6 engines are inherently unbalanced, regardless of

483-516: Was "the best-kept secret in motorcycling" and a "forgotten gem", comparing it to the 270° Norton Commando 961 . In 2014, Steve Cooper said it is, "Very much the thinking man's sports bike, this slightly oddball twin is beginning to reach cult status and for good reason". Despite being considerably cheaper than the Ducati, the TRX did not sell well, and production ceased in 2000 with no obvious successor. Although manufacturers have occasionally adopted

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506-476: Was a SOHC 12-valve engine produced from July 1988 through January 1997. It uses Hitachi sequential electronic fuel injection , and features cast steel connecting rods , a half-counterweighted cast steel crankshaft, and a cast aluminum cylinder head. The 2.4 L (2,389 cc) KA24DE was used in many Nissan cars and trucks. Most KA24DEs bound for the US were built in the city of Aguascalientes, Mexico , with

529-413: Was the first production motorcycle to have this design. The 270° crank has an ignition sequence and an engine balance that yields something of the feel of a V-twin . Unlike 180° and 360° parallel-twins, a 270° engine in motion never has both pistons stationary, so its flywheel momentum is continuous. With less vibration than a 360° crankshaft, and a more regular firing pattern than a 180° crankshaft,

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