89-97 Katana 36mm carb install and home jetting on 1100E

[Anonymous]

I picked up a set of Katana 750 carbs for $20 bucks and decided to install them on my GS1100E. Since I am working on a blowthrough Turbo kit for the bike I decided to add these carbs and jet them for K&N pod filters and a 4 into 1 pipe so I could ride the bike and still get some performance improvement. The carbs are a perfect fit for the GS. First. The stock 1100E throttle cable works perfect. I did have to do some adjusting for pod filters but spent no Extra money doing this. I turned the fuel screws 3 turns out. I had some jet size drill bits so I drilled the stock jets in the carbs out to various sizes untill I got it right. I ended up stopping at a 140 main. You have to use JB weld or something to stop up both lift holes on all the slides. ( If you don't do this it will never take wide open throttle). sand them back smooth after it drys. You could just buy needles but I took my end grinder with a flapper wheel on it and tapered the stock needles to get what I needed. ( Not exact but close on the eyeball meter) I tapered the end to a finer point and then 1/4 inch back up the needle from the bottom I reduced the diameter. I already had the filters so no extra turbo money had to be spent. I got the $20 for the carbs from my wife The power increase was great. The bike pulls much harder and has instant throttle response. It pulled so much harder that the clutch started slipping on the top end. This was something it had not done with the stock carbs? I guess new plates are in order now. The point is Katana 36mm 750 carbs are the same from 89-97 they are much cheaper than the GSXR carbs and easy to find. Factory and K&N offer stage 1&3 jet kits for them and they are a perfect fit.

 

[Jethro]

You have to use JB weld or something to stop up both lift holes on all the slides. ( If you don't do this it will never take wide open throttle)

I'm curious as to why this is the case? When a jet kit is installed, they say you have to drill out the slide vents larger to work right? Makes sense becasue as the fuel volume is increased, the air pressure for the slide diaphram also needs increasing. Are the Katana carbs CV carbs?

 

[Anonymous]

Yes they are stock CV semi-flatslide type carbs. While drilling out the slide holes is the norm, some CV carbs require you to plug the holes. The slides lift to quick for the GS applacation and you get a full rich condition instanly which will cause the engine to break up at full throttle and not recover. With the holes plugged it is a much smoother transistion to the main jet. I have ran into this in the past trying newer style CV semi-Flatslide carbs on bikes before. Not very Technical I know but it works. This would be my 2 cents on what is happening someone else might have a better explanation.

 

[RacingJake]

Make's me wonder if there's some other port in there and the holes in the slide are the bleeds ?

 

[Anonymous]

The holes in the slides are the bleeds. The intake port for the slide is the small opening above the rear bell.

 

[Anonymous]

Hey, after researching the PDF files on dynojets site, it looks like a lot of the katana and GSXR kits include "inserts" for the slide holes, it does not sound like they completely close them, just make the crosssection smaller. They also mention removing one of the inserts as part of the tuning process as needed.

Still working on my Kat carb project, just had to sideline it for a little while. Preparing to move to Temple, TX for my residency. Busy, Busy


Derrick

 

[Anonymous]

I tried one hole plugged, Still went rich. one hole plugged with half size on the other, same thing. With both holes plugged the bike ran great today.

 

[Anonymous]

Some of the kits also mention a new slide spring, maybe a higher spring rate to slow the rise of the slide?
I am currently running the Kat carbs with .5 mm shims on the needles and 130 mains and am running a little lean, but not bad. The pods I am running are from my old carbs and are probably a little more restrictive than the KN of oval filters.

 

[Anonymous]

Some of the kits also mention a new slide spring, maybe a higher spring rate to slow the rise of the slide?

My K&N kit for my ZX-9 had new springs that were stiffer than the OEM ones. It also had me drill an extra hole in the slide, but it was noted that the hole was optional. The slide motion has to be balanced with the vacuum force and spring rate used to get things working correctly. There is no reason to expect that changing one of these variables will not require changing the other to make things work again.


Mark

 

[Anonymous]

My saga continues, (feel like I should have my own theme music by now) thought I would update all those interested.
On the 96 Katana 750 carbs on my 83 GS1100E
After numerous changes and tweaks, the combination that seems to be working the best is:
- stock pilot jets, 42.5
- stock needles with a 0.5 mm shim
- 137.5 mains
- modified slide springs, what I did was purchase a close out K&N jet kit for a 99 Bandit. Seemed like a good price for a wide selection of jets, but what found was that the kit also included a set of new slide spring with some what higher rate than stock. They were a little longer than the stock too, but I cut them down so the relaxed length matched. It slows the slide down just enough so that I do not need to close the vent holes, and prevents the bike from bogging when whacking open the throttle.
- I also found that (while repacking my yosh can) the yosh can narrows at the exit to a diameter the same a one of the primary tubes. I removed the restrictive part of the baffle, and with the repacking, I get better flow with about the same growl.
- emgo pods, decided that the interior diameter of the mounting flange was the restricting factor in my top end tuning, so I removed the steel bottom of the filter, and fashioned a rubber mount that matches the diameter of the filter bottom, as well as the carb mouth. So the only restriction is the action of the filter material itself.
:roll: can you tell that I have gotten an ultimatum (on threat of mutilation that should not be mentioned in public) not to spend any more money on my bike for a while?

It is running well, pulls well of idle, picks up at 3500, really comes on at 7000.
Idle is not perfect, once it really warms up it occasionally dips down a couple hundred rpm then pops right back up. But it doesn't die. And I occasionally get a very mild hiccup accelerating out of a corner in second gear, around 2100 rpm, but only occasionally. Still the best Idle I have managed with either set of carbs.

Its getting fun again

 

[Anonymous]

Carb change on the GS11. I bought a 2001 Katana 600 with a bad motor. I put a 90 GSXR750 motor in it. the stock kat 600 carbs are too small for it. I am using the Kat 750 carbs on it and so I am going to put some Bandit 1200 carbs back on it. With pod filters. stock needles from a 95 Kawasaki ZX7R, 160 mains. Runs like a champ.

 

[Anonymous]

After some more tinkering and riding, a change to my above post.
After enlarging the distal baffle in my yosh can, I have gone back to the stock 96 kat slide springs with the above jetting and I am much happier with the midrange and accelearation.


Derrick