If each motorcycle manufacturer has its own genes, there is no doubt that, at Honda, the engine is part of the DNA of the Japanese manufacturer.
Throughout its history, the latter has always favored power and sophistication, sometimes even if it means letting the pilots get by with a “trestle”…
But for lovers of fine mechanics, Honda represents a bit of a dream, this is still the case today with the top of the general public range offered by the Tokyo firm.
After having released a Street Legal version of its MotoGP RC213V, the real piece of goldsmith's work RC213V-S intended for 200 happy and wealthy owners, Honda set out to offer even more powerful (and much less expensive) for the big public, the new CBR1000RR-R.
Basically, the challenge was clear: take as much of the technology learned as possible by building the RC213V-S V4 to adapt it to the in-line four-cylinder of the CBR 1000RR-R, while developing a little more power and retaining the reliability of a general public motorcycle sold in dealerships.
With 218 horsepower at 14 rpm compared to 500 or 159 depending on the versions of the RC 214V-S, the bet is won, at the cost of a lot of effort, some of which we will dissect.
Honda therefore took the RC213V-S engine as a model. This is directly derived from MotoGP, with the main modification being the abandonment of the pneumatic valve return in favor of classic springs. Its bore is therefore 81 mm, a figure directly taken from the MotoGP regulations and 5 mm larger than on the previous model.
For those who haven't seen it yet, enjoy this video...
We therefore find this bore on the CBR1000RR-R, as well as the 19° angle formed by the intake valves (2 mm larger) and exhaust valves with the aim of increasing thermal efficiency by making the chamber more compact combustion.
The central intake ducts, as on the latest versions of the RC213V, explain for example the movement of the position of the ignition key.
“For the adoption of central ducts, we aimed to improve the efficiency of the intake by making it the same size as the RC213V. As a result, the frame was also remade and the position of the conventional ignition key interfered with this huge conduit, and so it was necessary to move the key to the left side. »
These words are from Yuzuru Ishikawa, the development manager, and are supplemented by those of Kensuke Mori (in charge of engine design) and Toshiaki Deguchi (in charge of engine research) who worked on MotoGP from 2009 to 2012 of the HRC…
“As there is a large bore and short stroke, the weight of the valves increases and the maximum rotational speed also increases, and so it was necessary to reduce the weight of the piston as much as possible. The piston is made of a high-strength material that was traditionally used only for the RC213V-S: the crown is thinned while increasing strength, and the skirt length is also shortened to the limit. »
Honda therefore worked with a dual objective of power and reliability, which explains the use of processes usually reserved for competition: for example the camshaft and the levers receive a DLC (Diamond-Like Carbon) treatment providing a coefficient 35% lower friction and incidentally excellent corrosion resistance, the small end bearings are machined from bronze/beryllium and the oil passages (with variable geometry for cooling the pistons) are omnipresent in and around the crankcases. of the crankshaft, just as the water circuits have been standardized to cause as little distortion as possible in the cylinders, and therefore as little friction as possible. The timing chain is shortened by no longer being driven directly by the crankshaft to be lighter, the connecting rods are made of titanium, the piston pin grooves are coated with nickel-phosphorus, etc., etc., etc., the list is long…
Although having increased the engine bore, Honda also worked on its longitudinal compactness, by modifying the primary reduction ratio and reducing the distance between the gearbox shafts. By now fixing the shock absorber directly to the engine casing via a support and by extending the swingarm, the CBR1000RR-R finds almost exactly the same geometry as a MotoGP, with a wheelbase of 1455 mm.
We could go on for a long time (and perhaps we will), but we can already see that we are dealing with a very, very, very sophisticated motorcycle, without even talking about the electronic or aerodynamic layers.
Japanese manufacturers have regularly produced series motorcycles which are true showcases of their technological know-how. Some were unaffordable for ordinary people (750NR and RC213V-S at Honda), others not (Yamaha RDLC500 and Suzuki RG500 Gamma for example).
In these times, it is all the more pleasant to greet a newcomer in this last category!
