With all of the different engine configurations available for sportbikes these days, including inline-four cylinders, inline-three cylinders, v-twin and v-four, why is it that the Japanese manufacturers stick with the inline-four cylinder formula? There have been very few exceptions (Honda’s RC51 comes to mind). Every Japanese manufacturer currently uses an inline-four-cylinder engine in its supersport class and open class sportbikes.
There is nothing wrong with this, of course. The engine design has certain qualities that are attractive. Four cylinders generally allow higher revs, and higher peak horsepower than engines of similar displacement with fewer cylinders, and the inline layout has certain advantages with regard to cost, weight and complexity. If it lacks anything, it is power delivery down low and that elusive “character”. The engine vibration and sound lack the uniqueness of a Ducati or a Triumph Triple, for instance. Of course, for many classes of sanctioned racing, you are also allowed a displacement advantage if you run fewer cylinders.
It is curious that the Japanese have not considered other engine configurations purely for marketing reasons. It often pays to be different, even if performance is not superior. The feel and sound of a triple, for instance, can differentiate your product, and perhaps create a lucrative niche (Triumph’s experience certainly does not argue against this). A Japanese middle weight v-twin sport bike would be so unique it might instantly be considered a collector’s item. Just some random thoughts this Friday afternoon. Email us with your own thoughts on this subject.
By the way, in response to some of the email, I am not only aware of the Suzuki SV650, I own one. It is the only street legal bike my family owns, and it is sitting my garage right now. I guess my article was not clear enough. I am talking about cutting-edge supersport and open-class sportbikes. 750cc twins are allowed to race in the supersport class, and 1200cc twins are allowed in the superbike class. The Triumph 675 Triple is a cutting-edge sportbike. The Japanese do not make twins or triples (at least for sale here in the U.S.) that currently fit this description.
