It might not look very different to the 2020 version but Honda’s 2021 CB125R hides two very significant upgrades in the form of a new engine and much-improved suspension.
The engine change comes, like so many 2021 updates, in response to Euro 5 emissions rules. To achieve the new targets Honda has switched from the old single overhead cam engine, which was inherited from the CBR125R, to a new DOHC motor that still measures 125cc but offers more power and torque than its predecessor.
That means the CB125R now finally achieves the 11kW (15bhp) mark that’s the legal maximum for L-plated 125cc bikes, up from the 9.8kW (13bhp) of its predecessor. Peak torque also rises from 7.4lbft to 8.6lbft. The numbers might be small, but they represent a significant 15% increase in power and 16% boost in torque.
The new engine appears to be derived from the motor that’s already offered in the Asian market CB150R – a bike that shares the CB125R’s chassis. It uses the same 57.3mm bore as the new 2021 CB125R, but to achieve the 125cc capacity Honda has cut its stroke down from 57.8mm to 48.4mm. In comparison, the old SOHC design had a 58mm stroke and 47.2mm bore. The compression ratio is also higher than before at 11.3:1 instead of 11:1.
With fuel injection, the engine achieves the all-important Euro 5 certification that will enable it to be sold here for the foreseeable future.
On the chassis side, the big news is the adoption of Showa Separate Function Big Piston (SFF-BP) upside-down forks. It’s the first time these have been used on a bike in the 125cc class, and they’re the same as the forks used on the much bigger 2021 CB650R.
The engine and suspension changes do add up to a slight weight increase for the 2021 CB125R, which comes in at 129.8kg where its predecessor was 126kg, but the improvements from the upgraded engine and suspension should more than make up for that.
For 2021, the CB125R will be offered in pearl grey, matte black, candy red or matte blue. Prices and availability are expected to be announced soon.