The Yamaha MX800V motor has two-cylinder, overhead valves and a ball bearing supported P.T.O. The engine is equipped with an industry-standard air filtration system; float-type carburetor; T.C.I. ignition system and electric starter.
The cylinder bore and the piston stroke is 80.0 mm (3.15 in) and 82.0 mm (3.23 in), respectively. The compression ratio rating is 8.6:1. The MX800V produces 26.5 HP (19.8 kW) at 3,600 rpm of maximum gross power or 26.0 HP (19.4 kW) at 3,600 rpm of gross rated power (SAE J1995) and 62.1 Nm (6.33 kg·m, 45.8 ft·lb) at 3,100 rpm of torque.
|Type||4-stroke, OHV, V-twin|
|Displacement||824 cm 3 (50.3 cu-in)|
|Max. horsepower||26.5 HP (19.8 kW) at 3,600 rpm|
|Max. torque (crank PTO)||62.1 Nm (6.33 kg·m, 45.8 ft·lb) at 2,200 rpm|
|Fuel system||Float-type carburetor|
|Ignition system||T.C.I. ignition|
|Lubricating system||Full pressure with filter|
|Starting system||Electric starter|
|Fuel used||Unleaded gasoline (octane number 86 or higher)|
|Fuel tank capacity||–|
|PTO shaft rotation||Counterclockwise (from PTO shaft side)|
|Maximum speed||3550-3600 rpm|
|Cylinder compression||13.4-14.8 kg/cm2 (190-210 psi)|
|Intake valve||0.07-0.13 mm (0.003-0.005 in)|
|Exhaust valve||0.07-0.13 mm (0.003-0.005 in)|
|Oil type||Yamalube 4-stroke or an equivalent (SE or higher)|
|Recommended oil||SAE 10W-30|
|Oil capacity||2.0 L (2.11 US qt, 1.76 Imp.qt)|
|Spark plug||NGK: BPR6ES|
|Spark plug gap||0.7-0.8 mm (0.028-0.031 in)|
|Spark plug tightening torque||20 N·m (2.0 kg·m, 14 ft·lb)|
Valve clearance adjustment data
Calculate the thickness of new adjusting pad so valve clearance comes within specified values.
R = Thickness of removed adjusting pad
N = Thickness of new adjusting pad
M = Measured valve clearance
N = R + [M – 0.13 mm (0.005 in)]
Adjusting pads are available from 1.80 mm (0.0708 in) to 3.00 mm (0.1181 in), in steps of 0.05 mm (0.002 in).
R = 1.80 mm
M = 0.22 mm
N = 1.80 + (0.22 – 0.13) = 1.89 mm, round to 1.90 mm, so we need a adjusting pad with code 190.
Adjust valve celarance at 1000 hr periodic maintenance, normal operational range between periodic maintenance may be 0.02-0.2 mm (0.0008-0.01 in)
|Rocker arm shaft bolt||4.0 Nm (0.40 kg·m, 2.9 lb·ft)|
|Cylinder head cover bolt||11.0 N·m (1.1 kg·m, 8.0 lb·ft)|