400ex vs z400

[cals400ex]

i know these bikes are quite similar in many ways and distinct in others. there is one thing i really don't understand. why do the z's respond better to engine mods? does it have to do with valves? i have read many times that the z will show more gains with similar mods and this just stumped me. explanations would be great.

[YardDog24]

The easiest answer is liquid cooling. It allows for tighter tolerances in a motor and more room to grow. And the better cooling allows for more mods because the system can handle it the heat better..

[Big - D Racing]

hear is your answer, despite the obvisous liquid cooling. The 400ex in stock form isn't really restrictive in terms of air flow and intake flow. So when you add a part on a 400ex that is a little more free flowing it adds minor power increases. The suzuki design is really restrictive and when you do stuff to open the flow of air up, it responds a lot better with big hp increase.
The same goes for a raptor. The stock exhaust is so restrictive that when you add a free flowing aftermarket system you can look forward to 8 to 12 hp gain! With a 400ex you get 2 - 3 hp, and with a Z400 you get like 4 - 7 hp!

[NTPRacing#19]

Big D is right, i think another reason is that the old technology of the 400ex isnt that responsive or sensitive to motor mods as such as a new technolog motor such as a the z 400.

[ChadEXer]

Everyone also forgot that the Z has a DOHC setup too!!