Yamaha XZ 550
|Engine||552 cc & 400 cc, 4-stroke, V-Twin, liquid-cooled, DOHC|
|Weight||212 kg (467 lb) (wet)|
The Yamaha Vision (XZ550) was a motorcycle produced in approximately 1982-1983, though a smaller XZ400 model was available in some markets until at least 1987. It offered innovative technology in its motor and bold styling.
The XZ550 was the first Yamaha model to feature automotive-style downdraft carburetors with the air cleaner box mounted atop the carburetors, as opposed to most motorcycles' sidedraft carburetors with their side-mounted air cleaners. While downdraft carburetors flow air into the engine more efficiently than sidedraft carburetors, the height of the carburetors and their airbox required Yamaha to design a large tunnel into the bottom of the gas tank. While the tank holds 17 liters(4.5 gallons) of fuel, it looks much larger thanks to the tunnel and suggests that the bike is top-heavy, which it is not.
The XZ550 has a water-cooled engine. At the time, most water-cooled motorcycle engines had fins, intended to suggest the cooling fins on air-cooled engines, cast into their cylinder heads. While fins are absolutely necessary on an air-cooled engine — they increase the surface area of the head, hence improve cooling—they serve no function on a water-cooled engine. By leaving the fins off the XZ550's engine, it simplified the engine's manufacturing process, reduced the amount of metal needed to make the cylinders, and lowered the cost of the engine without affecting its functionality.
The Yamaha Vision was originally conceived in the late 1970s when motorcycling was at its peak, and spent three years in development, being overseen by a small group of designers and enthusiasts rather than "committee think". Several high profile external design houses contributed to the design of the XZ550 including GK Design Associates for design, and reputedly Cosworth for the engine and Porsche for the final drive. The initial models were designed to be a performance bike and GK's goal was "to make it into the most advanced super sport bike in terms of both styling and riding performance" The XZ550 succeeded on both fronts, its comfort on long rides and veritable torque-monster engine matched by its distinctive deep V-Twin exhaust beat and neck-snapping performance. Sales were poor and it was not until the bike was re-invented as a touring bike in 1983 that sales picked up, although not enough to see the bike surviving. The bike was considered "rather B.M.W.-like", in reference to its touring credentials, and "the most European motorcycle from Japan in recent memory."
Unfortunately, producing an entirely new product from scratch is never without initial problems, and the Vision suffered from a few. An off-idle carburetion quirk, known as the "Vision stumble", meant the first year machines were prone to initial stuttering on part and full-throttle takeoff. The "Vision stumble" problem, after months of research, was finally solved by racer Marc Salvisberg, who later started Factory Pro Tuning. The problem, it seemed, wasn't a Yamaha development problem at all, but was actually a lean spot, just off idle, caused by what appeared to be residual casting sand that filled the off-idle bleed holes at the throttle butterfly plate in the Weber-style Mikuni carb. That information was immediately relayed to Yamaha U.S., where it was relayed to Japan and verified. The 1983 models carbureted essentially flawlessly. (This claim of a "solution" is disputed by experienced XZ550 forum contributors as a myth - the likelihood that residual casting sand consistently affected the performance of all the 1982 models is highly improbable. Meanwhile, other riders have successfully overcome the "Vision stumble" in their 1982 models without changing carburettors.)
In the 1982 model, lightning quick steering was considered too extreme for some, though was highly appreciated by sporting riders. The weight distribution was 55/45 and the lightly loaded front end benefited from the installation of a slightly larger than usual front tire. The front suspension was described as too soft, the rear, even with an adjustable shock, difficult to dial in. On the electrical side, the Vision had "a well deserved reputation for eating starters and stators." There is also a problem with the starter clutch. It has a tendency to loose a three bolt fastening in the starter clutch mechanism.
The US 1983 model Vision fixed most of the faults, with an improved carburetor eliminating the stumble, air adjustable front forks firming up the ride and improving the roadholding. A full fairing, with adjustable hot and cold air vents, effectively shielded the rider. With the improved carburetor and minor internal adjustments, the engine's strengths became apparent: it had enormous torque at all revs, and would pull from idle in top gear. Despite the 10,000 R.P.M. redline, the oversquare bore and short stroke kept the piston speed low, with the result that the engine always sounded relaxed, even at peak revs. The exhaust note has been compared to that of a Ferrari Testarossa (which came out several years later.) With its unique "hang support" frame, whereby the engine is suspended beneath the frame for lighter weight, the Vision's performance and roadholding were far ahead of its time. Unfortunately, so too was the cost. The motorcycling boom of the Seventies was already receding before the XZ550 hit the showroom floors, and rival motorcycle companies offered cheaper motorcycles without the quirks. The model was discontinued from sale in the U.S. in 1983, though it maintains cult status online. In current times, the XZ550 has been found to be one of the easiest motorcycles to modify to the owner's personal taste. There are "bobbers", full touring bikes, cafe racers, and general sport bikes in all areas of the world. The online forum for the Vision,www.ridersofvision.net, is a very informative and most complete location for finding repair information, rider help, ride reports and information known to this date.
At least thirteen major models were produced.
- 11U European model - available in unfaired, or fully vaired variants (XZ550S) with many minor regional differences
- 16R Australasian model - available unfaired, with sales promotion full or bikini fairings. Marketed as XZ550R
- 11V German model - a 50PS low power version
- 11H USA/Canada model - 1982
- 11J USA/Canada model - 1982
- 11K USA/Canada model - 1983
- 28V USA/Canada model - 1983
- 28W USA/Canada model - 1983
- 30R Japanese model - unfaired
- 25R Japanese model - fully faired. Marketed as XZ550D
- 14R Japanese model - a 400 cc version unfaired
- ??? Japanese model - a 400 cc version with sport fairing. Marketed as "Air Current"
- 24R Japanese model - a 400 cc version fully faired. Marketed as XZ400D
Major differences between models included Single / Dual front disc brakes, Suspension, Air box, Carburettor (BD34, BD36), Paint schemes and branding (the XZ550 is branded as Vision in the US). As well as the full fairing, a smaller sport fairing was available, and offered as a purchase incentive for unfaired variants.
The 400 cc version was sold from 1983 to 1987 and is visually almost identical to the 550, although it has sightly different height, width, length and weight specifications. It was sold in full faired, half faired and naked versions. The XZ400 was sold into non-U.S. markets (including Europe, Japan, Australia and New Zealand). The most obvious differences other than engine capacity were slotted disc brake rotors, and a strap on the seat. Most parts are interchangeable, although the 400 had a different bore and stroke, valve sizes making engine part swaps difficult.
Three different gear ratios exist for the European/Australasian, US and Japanese markets. These are relatively easily swapped between models, allowing rides to select between lower-revving touring style riding, and faster acceleration.
- 4-stroke 70-degree DOHC V-Twin
- 4 valves per cylinder
- 552 cm³
- 65 hp (48 kW) @ 9500 rpm
- 50 N·m (37 ft·lbf) @ 8500 rpm
|Model Designation:||XZ550, XZ550S||XZ550R||XZ550||XZ550RJ||XZ550RJ||XZ550RK||XZ550D||XZ400|
|Market:||Europe, Canada||Australia, New Zealand||Germany||Canada||USA||USA, Canada||Japan||Japan, Australia, New Zealand|
|Model ID:||11U||16R||11V||11H||11J||11K, 28V, 28W||30R, 25R (D Model)||14X, 24R (D Model)|
|Colours:||Silver, Red, White/Red(XZ550S)||Silver, Red||Silver, Red||Silver, Red||Silver, Red, black||Silver, Red, Black||Grey||Silver, Red, White/Red, White/Blue|
|Key Identifiers:||Swoosh decal, low risers, rearset pegs, progressive fork springs, "XZ550" side badge, fairing optional (XZ550S), unslotted rotors||Similar to 11U model||Visually same as 11U. 50 PS Model. Frame Serial Number 11U-050101 onwards. Different cam and jetting.||High handlebar risers, "vision" side badge, single front disc brake, side reflectors, no fairing||High handlebar risers, "vision" side badge, single front disc brake, side reflectors, no fairing||BD36 Carb, low handlebar risers, rearset pegs, "vision" side badge, side reflectors, fairing/tank decal, gold wheels, fuel gauge, vacuum air flapper, fairing, slotted rotors||Slotted rotors, seat strap, grey color scheme, fairing optional||Slotted rotors, seat strap, XZ400 side badge (silver), silver tank badge, XZ400 color scheme, fairing optional (XZ400D)|
|Engine||4-stroke, liquid-cooled, 70° V-twin two-cylinder, DOHC, 4 valves per cylinder|
|Capacity||552 cc||398 cc|
|Bore Stroke:||80.0 x 55.0 mm||73.0 x 47.6 mm|
|Fuel System:||Dual Mikuni BD34, downdraft carburetors||Dual Mikuni BD36, downdraft carburetors||?||Dual Mikuni BD34, downdraft carburetors (without fuel pump)|
|Ignition:||TCI (Transistor Controlled Ignition)|
|Transmission:||5-speed, constant mesh|
|Overall Length:||2210 mm (87 in) 2255 mm (89 in) in Switzerland, Sweden, Denmark, Norway and Finland||2120 mm (83.5 in)||?||2145 mm (84.4 in)|
|Overall Width:||750 mm (29.5 in)||845 mm (33.3 in)||?||750 mm (29.5 in)|
|Overall Height:||1110 mm (43.7 in)||1090 mm (43.1 in)|
|Seat Height:||775 mm (30.5 in)||780 mm (30.7 in)||?||775 mm (30.5 in)|
|Wheelbase:||1450 mm (57.1 in)||1445 mm (56.9 in)||?||1455 mm (57.1 in)|
|Weight (wet):||215 kg (474 lbs)||212 kg (467 lbs)||?||215 kg (474 lbs)|
|Primary Drive Gearing:||34/72 (2.117:1)||33/73 (2.212:1)||31/74 (2.387:1)|
|Suspension Front:||Telescopic trailing axle fork, Progressive spring||Telescopic trailing axle fork||Telescopic trailing axle fork, Air damping|
|Suspension Rear:||Monoshock, rebound adjustable||Monoshock, rebound & damping adjustable|
|Brakes Front:||Dual hydraulic disc||Single hydraulic disc||Dual hydraulic disc (Slotted)|
|Brakes Rear:||Drum (Mechanical linkage)|
|Tires Front:||90/90-18 51H||100/90-18 56H||?||100/90-18 51S|
|Tires Rear:||4.25/85 H18||110/90-18 61H||?||110/90-18 61S|
|Rims:||Tube Type||Tubeless Type||?||Tubeless Type|
|Fuel Tank Capacity:||17 liter (4.5 US gal)|
- [Yamaha OEM Parts catalog: http://www.yamaha-motor.com/sport/parts/home.aspx]
- . Choate, Curt; John H Haynes (1991). Yamaha Vision Owners Workshop Manual. California, USA: Haynes Publications, Inc. ISBN 1-85010-761-0.
- Yamaha Motor Co.,Ltd. (1985). XZ400 Supplementary Service Manual 14X-28197-20 to XZ550RJ Service Manual 16R-28197-60 (1st ed.). Japan: Yamaha Motor Co Ltd. p. 26.
- Yamaha Motor Co.,Ltd. (1982). XZ550 Service manual part number 11U-28197-80 (1st ed.). Japan: Yamaha Motor Co Ltd. p. 81.