This project has been 2 1/2 years in the making, anyway, what I was planning was to add 1988 GSX-R 750 carburetors, the oval ones, I just did not want to add the pods as it would look like it was a 'highly' modified Kat, I wanted to keep the stock appearance as much as possible, so I had to find a way to adapt the stock plenum and filter to these carbies, and thus also not having the problems when pods are used.

I finally got some reasonable parts for the 36mm jobbies I had bought years ago of E*ay, the slides were shot, emulsifier tubes no good etc. etc. BUT, they were Dynojetted 136!!

To modify the stock plenum, I first cut away the stock velocity stacks and trimmed a bit more to fit the velocity stacks from the 1988 GSX-R 750 carburetors, then I trimmed the outside to fit into the plenum I had trimmed, I then mounted it all and the space that was between the plenum and the stacks ( that were mounted on the carbies) I filled in with some of that quick setting plastic weld stuff, that gave me the distance and alignment that was needed so that I could get the plenum mated to the stacks by a plastic welder, unfortunately, they could not be welded as the materials are different, so Sikaflex was used.

I finally fitted the fuel lines and then started it, after a few minutes it settled to a nice idle of around 1100 rpm, I thought I set everything up before I mounted them, the air screws are set to 2 1/2 turns out and the idle adjustment was a pure fluke, so far so good, the filter box and plenum is from TFB (thanks Mike, the lid is a treat, others may want to do the same after seeing this pic).
The throttle cable is too long and I'll have to shorten it, I'm thinking that maybe a solderless nipple may fit or perhaps I'll silversolder another nipple on it, we'll see....

Here are some pics of the job, it might look a bit messy, but it is a proof of concept.
More pics will follow later.

Overview.

Inside view of plenum.

Filterbox by TFB.

I've been a bit busy the last couple of days, so been a little slow on it, however, I put it all back together and did what I could with the throttle cable, its got a LOT of freeplay but I've got a couple of ideas I want to try first before cutting a perfectly good cable.

Well, I took it for a spin today, only a short one though and I can report that the difference is amazing, the mid range is REALLY strong, it pulls from 1500 hard and gets to 5000 real easy, I did try it to 9000 and it pulled hard and evenly all the way to it (not on a public road of course), there are no flatspots either, it just pulls hard whatever revs you are doing, I think a dyno is in order to check what the output is now.

It is a bit rich (judging from my nose) at idle, I think I will try screwing in the air jet from 2 1/2 turns out to 1 1/2 turns out and see where that goes. (1 1/2 turns no good, ran like crap, back to 2 1/2 now)

One thing that is missing now is that fabulous Kat Krackle on the over-run, might have something to do with being a bit rich too...
(there is a bit of a crackle now, must have had a bit of crap in them for a bit earlier)

I'm leaning towards a "Sleeper" (sleeping?) Kat, or a wolf in sheeps clothing...

Here is a photo of how it looks now, I wonder how many people will think that is how they came originally????

 

I had a bit of time this morning before I went to work so I decided to try what was going in my head on the "adjustment" of the excess length of the throttle cable, what I was thinking was adjusting the throttle RETURN stop so that it would take up the slack, I did not want to cut a perfectly good cable and also I could just put an original unmodified Katana cable in if ever I had to replace it.

On inspection of the housing, there is a ridge for the throttle RETURN stop, all I did was use some of that 5 minute plastic repair putty stuff and "extend" that ridge, here are the pics, they do not show a great detail, but it should give an idea of what goes on, it works well

This was the first trial go, the "stop" was not high enough, had to add more....

This was as far as I could go with the putty, it was up to the top of the housing, but it is enough

And this is how the adjuster looks now, plenty of room for fine adjustment

Cheers and I hope it all goes well with whoever tries to repeat my mods.