The Honda CB250RS is a 250 cc motorcycle designed for road use. It was produced until the mid-1980s. It has a high-compression four-stroke, four-valve, air-cooled, single-cylinder engine, which was an upgrade of the engine built for the earlier XL250S trail bike. The RS is known for its slim build, with a dry weight of only 128 kg, and nimble handling. The engine featured counter rotating balancers, which reduced vibration and allowed a lighter frame. Further weight savings were achieved by making the engine a stressed component. Early models were kick-started (with an automatic decompression lever), while later Deluxe models (designated RS-D / RSZ) came with electric start and different paintwork. The bike has a front disc brake and rear drum brake, and while it had only a single-cylinder, it had twin exhausts; one for each port.
The engine generates modest power and achieves a top speed of around 136 km/h or 84 mph. Early models produced a claimed 26 hp, while later, twin cam type models claimed 33 hp. It claimed fuel efficiency of up to 70 mpg (3.4 L/100 km). Known issues include failed ignition coils and CDIs although this is rare, even at 40 plus year old . Lack of battery cranking power can be an issue with the RS-D as the battery has not been upgraded and uses the same 9 amp battery.the starter system suffers as a result,compounded by the poor design of the actual starter..other problems include cam/head wear, usually caused by lack of oil and filter screen changes..very high mileage hard used bikes can crack the head between valves, but in general,with good servicing, these bikes can see 60 to 80,000 miles often