Theoretically, a 390cc engine is faster compared in all aspect
ratios(performance, speed, pickup, .etc.) compared to a 250 cc! But Yamaha is known for its mind blowing engines! if u check on r25 page, compared to all 250 cc engines, The yamaha r25 is clear winner! Yamaha designs their engine and get the most out of it that it’s really unbelievable! And when it comes to pricing Yamaha bikes are always costly, but u get more value for ua money.On the other hand, if u are average consumer and want to get more performance, this is very KTM took it’s strategy and are going to release at a lot lower price! Hence, it depends on what is your basic need, The high class or the Consumer friendly and powerful! This is where KTM excels! KTM RC 390 is clear winner! The Aerodynamic windshields gonna kick more speed to the the bike compared to the non-rc naked ktm 390