Kawasaki Sportsbike Riders Club - Australia - Online Forum

Before this knowledge gets lost out of a Clean Air Circuit - I'm wondering if anyone knows the logic of carb set-up of the detuned later bikes? I know the following facts:

US spec A1 CVK34 Main Jet #135/138 = twin port air intake = 115hp

AU spec A8 CVK34 Main Jet #100 = single port air intake = 108hp

Obviously they use a different needle but all of the other carb specs seem identical.

Now from what I can deduce a #138 main jet has twice the area as a #100 - hence the AU carbs can draw 1/2 the fuel so only need half the air to get the air:fuel ratios about right - hence one of the ports of the intake is blocked.

But what has me bemused is that there is ONLY a 7hp difference in quoted power.

I know actually getting to them is a different story, but returning the A8 carbs to the A1 spec is relatively cheap & easy to do - but with only that slight power increase the associated reduction in fuel economy just doesn't seem worth it.

I don't recall ever reading that the later bikes had anything else related to engine breathing different- but maybe they did?

I can't help think I'm missing something here....

I read that the small carb bikes have more power down low but less up top. I converted mine to big carb. If you are REALLY patient my second GPZ has the small carbs. One day I'll get around to fixing the engine. Got other bikes in front of it though.