Honda CRF150R thumper
By TMX Archives on 7th Sep 06
Honda springs a CRF four-stroke surprise - Radical CRF150R thumper launched WITH a formidable reputation for making ground-breaking and revolutionary developments that have shaped the history of motorcycling, Honda announced details of another milestone motorcycle in the off-road market today and changed the face of Youth motocross forever with the launch of the much-rumoured first-ever 150cc four-stroke machine eligible to compete alongside 85cc two-strokes.
Designated the CRF150R (CRF150R2 in the case of the Big-wheel version), the historic machine marks the biggest shake-up of Youth motocross since the arrival of Yamaha's 250F to the 125cc class, the first major new model to be introduced to the purely Youth market for many years, and the first time modern high-performance four-stroke technology has been available to the Youth market.
With the phenomenal success of four-stroke machines over recent years and Honda's known commitment to a four-stroke-only future it was inevitable that four-stroke technology would be developed for the Youth market sooner or later, but with the launch of the CRF150R to the world today Honda has significantly redefined the 85cc class and it's future. Whichever way you look at it the CRF150R is the most important and significant model of 2007.
Obviously 100 percent new right across the board, from the frame to the cables, the CRF150R has been developed by Honda to produce revolutionary, class leading power and performance whilst remaining competitive with the two-strokes in the price department, and as the promotional images show, it looks like a serious weapon that will leave a huge and lasting impact.
Based around a scaled-down version of the four-valve, Single Overhead Cam 'Unicam' motor, the design has been used successfully on the CRF450 and CRF250 machines, with which it shares many proven features. The CRF150R motor features steel exhaust and inlet valves, carburized steel cam, crankshaft, and connecting rod for optimum performance and durability, Honda's unique twin-sump lubrication system, a close-ratio five-speed gearbox with six-plate clutch, lightweight steel exhaust header with re-packable aluminium silencer, and 32mm Keihin FCR flat-side carburettor with TPS. The whole motor assembly weighs-in at 19.8kg and with a compression ratio of 11.7:1 it produces a claimed maximum power output of 16.6kW at 12,500rpm, which equates to an impressive 22Bhp, and maximum torque reading of 13.6Nm at 10,000rpm.
By comparison the claimed readings for the CR85 two-stroke are 15.5kW (20Bhp) at 12,500rpm and 13.4Nm at 10,500rpm.
Interestingly, Honda has opted to use a semi-double cradle type steel frame for the CRF150R instead of the perimeter-type aluminium chassis utilised on the bigger machines, one would suspect so as to keep the cost of the machine down, but the frame is an all-new design and is teamed with a new subframe, aluminium swingarm, revised suspension settings to the Showa forks and shock, new smaller capacity 4.3litre fuel tank, new seat and plastics, resulting in a machine that looks completley different to the two-stroke CR machines and arrives slighty taller, longer and wider than its long-established sibling as well.
As you would expect from a four-stroke machine the CRF150R weighs-in slightly heavier than the two-stroke CR's with the kerb weights of 80.3kg for the Small-wheel version and 82.3kg for the Big-wheel, meaning that both top the scales some five kilo's heavier than the CR85 machines.
With T+MX News scheduled to test this ground-breaking machine very soon we will be the first to be able to bring you a full rundown of the array of developments on the CRF150R, and more importantly tell you exactly how it performs and shapes up against the two-stroke competition out on the track. In the meantime, you'll just have to sit tight andMmarvel at this extraordinary example of engineering that will change the face of Youth racing for ever.
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