Hi guys. Looking at a new engine and I would like the ZX12R hairdryer. But I don’t know the differences between the older 2001 model and the newer one. Is there a power difference between the two or is it small alterations only?

Thanks lads

Andy

I've got an '01 ZX12r and I believe it is the same power output as the others up to '05? 178 BHP, and around 98NM torque IIRC.

There's alot of internet rumour about the '01 model being very difficult to de-restrict but I've never seen any actual evidence of it. Apparently the newer ones have a stronger clutch.

There is a difference between the mounting points on the older ones on the manifold side they have 2 bolts spaced towards the outside edge of the motor and on the newer ones they have a single mount in the centre.

The ZX12R was launched in 2000, this particular model is known as the A1 model. This was the only model that is derestricted for top speed as standard. All later models are restricted to 186mph, although models upto 2003 can be de-restricted with a Muzzy Bonneville Box.

The A models made in 2000 & 2001 (A1-A2) have a lighter crank than the 2002 -2005 models (B1-B4). The lighter crank helps the engine to spin up quicker, but it also increases engine braking. Kawasaki beefed up the crank in the B models which makes them smoother to drive with less engine breaking, thereby maintaining engine speed through corners off the throttle.

In 2001, the ZX12R got different cams and different throttle boots along with the electronic limiter (186mph). All else remained the same. The 2001's were said to make the same top end power but have a little more grunt in midrange.

In 2002, the ZX12R got a major revamp. These are the 2nd generation 12's (The B models). The important engine upgrades for BEC's are the heavier crank and oval throttle pulley.

In 2003, the engine remained the same.

In 2004 the ZX12R got a few more upgrades:
Secondary throttle blades (probably slows the airflow but smooths out throttle response)
New fuel/timing map in the ECU and 32bit instead of 16

2005, same as 2004.

The differences between the A and B models is said to be definately noticable. The B model is smoother, and easier to control on the throttle mid corner. The A model was however more 'raw' but not any quicker.

You'll not go wrong with any model of ZX12R but IMO, the 2004 & 2005 engines are slightly more refined.

Phil

as always nice comprehensive answer Mr Hellfire

yep it is. Would have U2U it to him direct but needed a quick answer.

Just rang Yorkshire engines (nice guy) who told me he didnt have any but knew someone who had a 2001 one in their garage. just waiting for a reply from him and wanted to know if the 2001 was ok to use (for some reason i thought it was down 20 bhp on the 2003 model).

He did say the older A models are better, they have an easier programmable ECU? and the fuel regulator is built onto the fuel rail making my current pump easier to reuse. Also the mounting bracket difference.

im taking my old engine out tonight because im impatient lol

cheers

Phil,

You mention the change(s) to the 2001 engine as camshaft and throttle boots? Do you mean throttle body there? If so do you know the nature of the change as I am not sure if I have the right throttle body for the engine I have. What I have noticed is a step change between the throttle body and the head of the order of 1mm (the throttle body is a bit wider diameter than the intake on the head)- surely Kawasaki would not have done this by design as it will have a negative impact on performance ?

I'l post a piccie if this is not clear

Cheers

- Paul

[Edited on 15/10/08 by progers]

As said 04> has the later ecu has the Kiss immobilizer.

The throttle bodies have two sets of butterflys, the second set is operated by the ecu.

The fuel rail has no return because again the pump is controled by the ecu.

The 1mm lip in the throttle bodies is where the rubber ram pipes sit.

Hi Big wasa,

The 1mm lip I am referring to is the lip between the throttle body itself and the head of the motor i.e. where it mates to the engine (the other end of the throttle body to where the ram pipes sit)

Still not sure if this is normal or if I have a mismatch between engine anf throttle body. did the throttle bodies change diameter between 2000 and 2001?

Cheers

Paul