Drill vacuum throttle gpz750?

Wookie58 wrote:

Injected wrote:

Not quite what Kawasaki Engineers signed off on.

Do you mean like putting an 1197 motor in a 650 chassis 

 the stock unit wouldn't fit with the mono shock and to be fair it was so restrictive it's ridiculous. I have never seen a stock air box on anything with so much baffling (I quite like induction roar)

 

How about this?


 

Nice sheet metal work

Here is a picture of my solution.

Without fabric cover

Is that actual filter foam or just normal foam ?

It’s filterfoam from ramair. Thought it would be the ideal solution for maximum power and low weight. Maybe possible to make it work with some experimenting with the vacuum slides but the cover will have to do for now.

Sixten wrote:

It’s filterfoam from ramair. Thought it would be the ideal solution for maximum power and low weight. Maybe possible to make it work with some experimenting with the vacuum slides but the cover will have to do for now.

You might want to consider a "dynojet" kit, trying to get the right combination of needle/jet/slide-speed will be a nightmare. If you are already "weak" then drilling the slides to increase their opening speed will probably make things worse

I will do some more experimenting with the hole diameter and maybe the cutaway part of the slide as well?
But that will have to be when the racing season is finished. 
It runs good now with the filter cover.
Or maybe just save myself some trouble and get a set of Mikuni VM or Keihin CR.
but they are very expensive.
 

If anyone is interested I solved it by stretching the CV springs about 10mm.
The problem was that the vacuum slides opened to much on low throttle and the engine run lean.
I think this is a better option than pod filters.
Less restriction then original airbox, still have the original intake runners and easy to remove.

There was a "DynoJet" kit on the CVK carbs I bought to run on my 750 Spectre engine. The slides vacuum holes had been enlarged by drilling. When I started the bike up the idle would fluctuate like crazy, this I attributed to the increased hole diameter.

I went back to stock needles and jets but the damage had been done to the slide bottoms.

To "correct" the hole size I made some thin washers that obscured the hole opening getting it back to as close as possible to the stock opening area. The washers were inserted on the inside of the slide bottoms slightly preloading the spring. This eliminated the idling issue without resorting to JB Weld and other messy solutions.