Montesa 4RT

It’s a four-stroke engine that leads the way in the world of trials when it comes to success. The Montesa Cota 4RT was introduced into the UK way back in October 2004 at the Scott Trial. Spain’s four-stroke development rider Amos Bilbao took the new machine to the best ever finish by a foreign rider, coming home in 3rd position. By 2005 Montesa production would move to the Honda four-stroke engined trials machines. In 2007 a very young Toni Bou would dominate the World Trials Championship and start a decade of domination for the new generation of machines unique to one model, the four-stroke Cota 4RT.

The winning formula

of this model has evolved from the 250cc single cylinder 4 valve OHC engine with liquid cooling, which was developed from the company’s successful CRF 250cc motocross engine but in the process was made more compact and lighter in weight. Another of its main attributes is a lightweight simple integrated injection system (PGM-FI) with a lower volume than a conventional carburettor. It comes in a single piece together with the throttle body and the ECU, its intelligent high-precision control unit. With sensors that perform instantaneous calculations of a wide range of variables such as the environment, engine temperature and atmospheric pressure, etc, it has grown a reputation as an ultra-reliable engine. The power delivery is through the tried and tested gearbox with a choice of five gears, with the engine power transmitted through a wet multiplate coil spring clutch.

UPDATES

The machine has seen many minor technical changes but the aluminium frame and swinging arm have remained very much the same, with the years’ models recognised by changes with the aesthetics. The major changes to the models came in the later part of 2013 as the 2014 models were introduced. Two new models were presented with major changes in two important areas: performance and styling. The new models were the 4RT260 and the 4RT260 Factory model which had the cylinder capacities increased to 258.9cc. The 4RT260 model carried the Montesa logos and offered a high base-level of performance for both the amateur and advanced competitor, fitted with Tech branded front forks and a R16V rear shock. For the more competition focused rider the 4RT260 Factory model carried the Honda badge and offered a more competitive suspension arrangement, which used Showa front forks and rear shock amongst a host of other upgrades and came in Repsol team colours. The use of the high specification Showa suspension package was reflected in the price, which made the Factory model more expensive. Both the new Honda and Montesa Cota 4RT260 models represented a big step forward for the fourstroke trials machines, and the increased engine displacement up to 260cc resulted in improved performance with a more usable power range, and stronger torque in the mid-range. The four-stroke engine braking had also been reduced significantly to provide enhanced rider feel and better control.

2017 MODELS

Three models are available for 2017 but here we will focus on the Cota 4RT260 and the Cota 4RT260 Race Replica.

COTA 4RT260

Our first look is at the Cota 4RT260, which features big changes in the styling as they have moved away from the traditional red to the elegant red, white, and blue HRC-inspired colour scheme, along with the chromed fork tubes that have black-painted bottoms which work well with the silver frame theme. Its appearance also works well together with the aluminium fuel tank, which sits between the twin aluminium frame spars. S3 branded handlebars are located under a Montesa bar pad, and the other significant change is the fitting of Dunlop tyres front and rear. Tech branded front forks and a R16V rear shock continue to be fitted. Black wheel rims with protective sidewall stickers finish off its appearance, which as always looks better in the flesh than in the pictures.

COTA 4RT260 RACE REPLICA

The Cota 4RT260 Race Replica stands very proud in its styling, giving it a very much ‘Toni Bou’ appearance with its Repsol Honda inspired colour scheme. The bond between the association with Honda and Montesa is further endorsed as the rear mudguard proudly carries the famous ‘M’ logo of Montesa, now located on the rear fender to give more presence while still maintaining the aesthetics of the machines ridden by the Repsol Team of World Trials Champion Toni Bou along with Japan’s Takahisa Fujinami and fellow Spanish rider Jaime Busto. The Repsol team theme is also reflected in the black frame and florescent orange wheels rims which give a very bold appearance. Dripping with carbon fibre parts to help with protection it also benefits from Renthal branded FatBars and grips, and the fitting of Michelin tyres front and rear. The high specification Showa suspension package continues its ‘Race Replica’ theme.

FOUR-STROKE POWER

Both new models are very similar engine wise as both still rely on the 260cc four-stroke engine from 2016, which benefited from a remarkable increase in power thanks to the adoption of a new fuel pump that provides a more controlled supply of fuel. This important factor, along with the mapping of the ECU (Electronic Control Unit) also offers a full power curve at low and medium engine speeds. Another highly significant aspect of the power delivery is the clear reduction of the engine braking which was already incorporated in the previous models. This is a feature of the four-stroke deceleration when the throttle is closed that was intelligently resolved by Honda engineers with a decompression system for the crankcase gases. Through this system, cutting fuel to the engine provides only a minimum engine braking effect, causing the motorcycle to feel much lighter and controllable. Both engines also use what was a world first when it was introduced. This is a high-performance generator that, when the kick-start lever is pressed, provides enough power to run the fuel injection system which in turn guarantees a quick and reliable starting method. For 2017 both models benefit from having longer kick-start levers to also make starting the engine easier.

Trial Magazine would like to thank Colwyn Bay motorcycles for the use of the two machines. Visit: www.colwynbaymontesa.com or call: 01492 535959.