RS34 Jetting on a KZ1000

Hello.

I would like to find out what kind of jetting people are running with their MikunI RS34 carbs.

I am currently running 17.5 pilots, 9DZH1 Needles in the 3rd clip (middle), and 120 mains. All float heights are set to 17mm with #2.5 float needles.

They're sucking K&N pods, and feeding a 1075cc Wiseco kit with Andrews 2x cams (.366 lift, mild duration/overlap) and a Kerker pipe (competition "baffle").

The bike seems to run fine, but it is a little boggy below 4k RPM. Pulls long and strong to 10k, with a big bump at about 6k. I just want to know if I'm on the ball or if my settings are way off of what others have. I have had a lot of people say that the main jet is very lean for my application but it does seem to run fine.

I am also getting some rich running/burbling between 4k and 5k rpm. i have been told to deal with it and not try and tune it out since its simply a resonance/double carburation issue. One suggestion I have had is to give the pipe a little more backpressure. Dunno.

Tips? Suggestions?

-Dave

Those carb settings seem fine. I have a very similar combo (RS34, 1075, 365 cam, 4-1 comp baffle) and similar settings. I'm running a leaner needle position and a 125 main.

Regarding the bog, make sure your accelerator pump is operating properly. They can be a little temperamental. Also, make sure the K&N pods are not binding against the A-pump rod. Even with a properly adjusted A pump you will encounter problems if you whack the throttle WO below 3 or 4K

Has the head been ported?

I have the accel. pump adjusted to start squirting as soon as possible and I'm having it use approx. 1/2 of its total pump stroke.

The head has been ported. I'm not that happy about it, and it was like that when I got the bike. Fill it in? I hear that porting/big valves/etc. is basically worthless on these bikes for street use and serves only to take away midrange.

-Dave

hi guys
i've just bought that 1982 kz1000
- mikuni 34mm
- k&N pods
- 4 into 1 exhaust
- carbs mixture screw 2 turns out
- floats ajusted 17 mm
- pilots 17.5
- jets 132.5
- needle jet in mid-position (third of 5)
and the carb is clean

theses are my symptoms:
on neutral, rpm 0 to 10k everything perfect

in gear when accelerating

rpm 0.750k to 4-4.5k everything's running good than it 5k start burping like crazy even full throttle no respond i tried also to close the choke while running ... no respond

after i drilled the jets with a 1/64 inch drill bit OMG ! worst worst worst !

is it a problem of jets setting or i would say its look like a fuel pump problem ?

im lost what i should do?

thanks

Sounds like an over-rich main jet or a loose needle JET (not a loose jet NEEDLE).

-Dave

If this helps:

My 1075 KZ1000 with stock cams, cleaned up head, K&Ns, Wieseco pipe and 34 Mikunis:

pilot: 32.5

main: 120

mixture screw: 1.5 turns out

needle: 6DP2, clip second from bottom.


Bike starts and runs beautiful, pulls hard throughout the rev range. It does have a slight steady throttle 4000rpm burble on hot days, but I attribute this to the pipe, which is a "rev" pipe. If I run a Kerker the burble goes away and I pick up tons of midrange torque.

17.5 pilots and 120 mains sound very lean to me with the combination you have Dave.

I'm confused about your needle number. I thought that the RS34 carbs took only 9-series needles.

9DZH1/2/3 OR /5

(going lean to rich)

-Dave

Agreed this sounds lean to me as well. The setup currently I'm dealing with similar bog but it's a 5K. Now granted your motor is bigger mine being a 750. I still have a #40 Pilot. Dyna jet needle on middle clip #3. Just placed 142.5 mains.

So given that I'm getting close to a good mix at most all RPM I'm assuming your on the lean side.

As for porting. Just leave it and try to find a setup that works well with the work done.

It's all about compromise sometimes.

Sean

Sorry, I should have been more specific. My carbs are not RS models, but are a slightly earlier model. The needle is probably similar as well but with a different number and series.

Sorry just noticed your talking RS and not BS.

Plenty of guys with this carb on the 1000. Should be some more posts. Looking at my RS (recently removed for BS34) that was tuned for the 750 will not get you where you need to be.

Good luck.

beefsquasher wrote:

The head has been ported. I'm not that happy about it, and it was like that when I got the bike. Fill it in? I hear that porting/big valves/etc. is basically worthless on these bikes for street use and serves only to take away midrange.

-Dave

My experience supports this hypothesis. I've done some extensive testing and tuning with port volume and have found no significant gain in HP from enlarged ports on a mild performance build. Increasing port volume only serves to reduce low/mid range torque, throttle response and fuel mileage.

The port on the left has a removable epoxy insert. On a 1075, 365 cam, RS34s, and 4-1 w/performance baffle, the open port (on the right) makes only about 3 more peak hp than the one with the epoxy insert but sacrifices torque, throttle response and fuel mileage.

Jetting for the two ports is similar with the difference being needle position. #3(center) clip postion for the open port and #1 position (leanest) for the epoxy port - Higher intake velocity at part throttle produces a much stronger signal at the jet hence a leaner needle postion. Both require a 125 main jet.

I've noticed that the guys with the most trouble tuning out carb related bogs and stumbles have enlarged intake ports...regardless of the carb they are using. I also had these issues until installing the epoxy inserts.

more info here
kzrider.com/index.php?option=com_kunena&...d=2&id=235189#238454

When you messed with the pilot jets did you leave those little black plugs out? PUT THEM BACK IN!!!! I had alot of people tell me these didn't matter but I did everything you could imagine to my carbs you could do this year. I even ground out the middle of 1/2 mill. thickness washers with a wood bench and a hand drill to shim my clip-less needle, WTF. to no evail it ran even shittier. I was so sick of making small little adjustments one jet at a time to eliminate doubt. I went for it and went back to a middle- of the road set-up for pilot jets on my my csr 1000 with v&h pipe and k&n pods. I then PUT THOSE LITTLE PLUGS BACK IN! after I cleaned them. the guy I got the bike from had the air screw turned way out to avoid going bigger on the jet, it worked before the pipe. I wen't up one extra on the main and started back at stock setting for the air screws. I then found the inside two cylinders to be running leaner to my surprise, I thought it would be the opposite. I dialed it in with the fuel/air screw and They're all burning even now. I guess you have to be darn close on the jets to try to fine tune with fuel/ air screws though. . I spent ALOT of time figuring this out from diagrams on the internet and tinkering around. The stuff that I learned was invaluable. I love my KZ, and it's a good thing I need to get into the heads, she's startin to leak, might as well cam just a little right? Winter project! Any suggestions for mild/moderate cams, size of bore, porting?, I'd like to say my future kz1000 streetfigher is pushing 120hp, at least.