Karosa B 731 is a model of the
Karosa 700 series. The B 731 is derived from the
Karosa C 734 intercity bus, and also unified with city bus models such as the
B 741 and the
B 732. The body is semi-self-supporting with
frame and engine with
automatic gearbox in the rear part. The engine drives only the rear axle. The front axle is independent, while the rear axle is solid. All axles are mounted on
air suspension. On the right side are three doors (first are narrower than middle doors). Inside are used leatherette seats, plastic Vogelsitze or Fainsa seats. The driver's cab is separated from the rest of the vehicle by a glazed partition (the first series produced until 1984 did not have a partition). In the middle, or in the rear part is room for a pram or wheelchair. Type B 731 (as well as whole 700 series) underwent during its long production many changes and modifications. Among the most significant belonged replacing of the noisy rear axles Rába with another that has not produced so much noise, change of the engine mounting and change the location of alternator, use of several types of engines
LIAZ, initially aspirated,
turbocharged later. In newer buses have also been used automatic gearbox
Voith (apparently from 1991) instead of the product of
Praga. Began to be mounted exhaust gas catalysators EKOS and between 1993 and 1994, the buses were equipped with intercooler and intake air (due to meet emission standards Euro1), which also led to modifications of the body – behind the third door was placed the intake grille. In the last buses from the year 1995 appeared motor
Renault. These buses were numbered B 731.1659 and were produced in only 50 pieces. Due to the assortment offered gearbox with retarder to the engines LIAZ cars were B 731 since 1994 produced with extended rear (the very first bus with a very similar rear was already made in 1992, it was a prototype B17). These were types B 731.1667 and B 731.1669 with
LIAZ engines and
Voith gearbox with integrated retarder. The rear panel is identical to then produced
900 series. == Production and operation ==