ZX9R carb interchangeablity question

[Jason]

Hi... I have a ZX9R B engine which I am fitting to a 1991 ZXR750 frame... all going well so far, but I need carbs for the 900 engine (which will be bored to take a Wiseco 950cc kit) . Does anyone here know if ZX9R C series carbs fit ZX9R B series engines? Alternatively, I have a set of 1996 ZX7R carbs..... would it be more or less practical to set these up to suit the ZX9R (950cc) engine??

Advice appreciated.

Jason

[Kev]

The C model carbs are spaced differently compared with the B model. The B model are equispaced whereas the C model aren't, wider between cylinders 2 & 3 compared to 1 & 2 and 3 & 4(see images below). The airbox fitment might be an issue too. They are essentially the same carb though, i.e. 40mm CVK, so unless you are willing to pull them apart and re-space them, re-route the throttle cables and modify the choke bracket, you might want to source a set off a B model, or better still get a set of FCR's which will really make your 950 sing. The ZX7 carb is smaller at 38mm, so will be too small.

BTW, are you Jace3791 selling the J model swingarm on ebay?

[Kwakked Up]

zx7 are also spaced differently.

If you get B model carbs remember they are restricted and don't open all the way.

[Jason]

Thanks very much for the informative replies.... greatly appreciated! I'm not aware of B model carb restrictions Kwakked Up?... can the standard B model carbs be modified to be unrestricted??

Alternatively might it be possible to build up a hybrid setup using C model carbs & utilising a B model butterfly shaft??... but seems like a lot of effort to me.

I don't want to use FCR's due to experiences I have had with them in the past.... CV carbs are better suited to my intended riding environment & are more maintenance friendly.. from my experience.

Kev.... yes, I am jace3791 selling the swingarm on ebay.... am rationalising my collection of stuff & trying to concentrate on projects that I want to finish.

Cheers
Jason

[Kwakked Up]

I just did the engine swap on my zx7 p model. Well worth doing.

The carb is an easy fix, on mine I just used the slides and diaphragm (vacuum valve) from the zx7. There is a plastic moulded section on the top of the slide that is higher on the b model and hits the carb top so doesnt open fully.


Can send pics if you like