kz900 carbs adjustments

[knut]

hi ,was servicing/ cleaning my carbs and need help on adjusting the throttle valves,they do have another screw under the top cover (mr pigford was correct thanks)but the workshop manual i have doesn,t cover these carbs,looking at the carbs #4 has a smaller gap than the other three,i presume thats not right ?what should the gap be and whats the method of checking them?
any help much appreicated ta knut

[Garn 1]

Knut, it is extremely important to have the gaps the same. By 'gaps' I presume you are talking about the gap at the bottom of the slide and the circular part of the throttle tube looking from the inside (engine side).

The book says 0.7 mm with throttle closed. A better way to check and adjust them, with the carbs off, is to use a couple of 3/16" ball bearing and doing two carbs at a time, open the throttle until the balls fall out at exactly the same time. For a quick fix, just bring the low or high one back to the settings of the other three. You most probably will be within the correct range to adjust the idle.

On the Mikuni 26mm carbs which were the standard carb on the Z900-A4 the adjustment is under the (high-top) cover and is quite obvious. Check that they are not 29mm smoothbores, which have a different adjustment.

Regardz

[knut]

thanks garn1,yes it,s the gap between bottom of slides and carb .the gaps that are there look alot bigger than 0.7 mm. i,ll measure the gaps and get them equal next week,i presume i can adjust the screws on top with engine running to balance the carbs correct ?

[knut]

oops forgot, the carbs are the standard 26mm ones.
thanks ,knut

[cra-z1]

When you bench set the carbs you want to adjust the gap on the side facing the air filter. There is a small notch on this side of the carb. I use a small wire which fits under the gap. It dosent matter what size the wire is as long as all of the carbs are equal. I tend to use a larger wire when setting up the carbs. if you take your time you will find the vacuum will be very close when you start the bike

[uk kev]

When you bench set the carbs you want to adjust the gap on the side facing the air filter. There is a small notch on this side of the carb.

This is where it gets confusing, I have four sets of carbs here, 3x26's, and 1x28's, only one of these sets has a notch at the base of the slide.
I set up what is my best bad set and the set I currently have on my bike, using a 1.0 drill, make sure you ave the tickover adjustment screw backed right off, then raise the slides, place the drill flat in the throttle opening, (engine side) and adjust the top screw until the drill just slides out when tipping the carbs over, repeat the same for all the carbs.
I only use a 1.0 drill as I can't get a 0.7 size wire.

[Garn 1]

Cra-Z1 & UK-Kev, I've just checked some 28 mm carbs and that little groove is on the inside (nearest the engine). If we measure the gap on the other side (air filter side) it has a cut-away section.
Regardz.

[knut]

well finally got around to putting carbs back in bike,new float valves,pilot jets, airscrews,adjusted slides equally to approx the right gap.cleaned everything ,air screws set at 1 1/2 turns out ,fitted new plugs .started fine running a bit rough down low but running ok.did some miles on ti last night must balance the carbs now and check condition of plugs too,have a feeling spark is not the greatest,newtronic ignition is fitted already to this bike, has anyone used this setup?
cheers for all yer help so far guys.

[Pigford]

Newtronics optical ignition was OK in its day, better than points, but a bit fussy
Its very important to set timing out of the daylight/sun, as this will confuse the systems optical sensors
A dyna system is leagues ahead, and as it happens, I will have a set for sale soon, low mileage;
Dyna S complete, good mechanical advance unit, Dyna coils (3 ohm) and a nice set of Taylor leads too!
PM me if interested

[knut]

i,ve clocked up a few miles on bike since,including running out of petrol miles from nowhere! (thanks to john who helped me out).
still not running great,checked plugs and found 1&2 black sooty , 3&4 clean lukin a bit lean.checked wiring on coils/newtronic ignition all ok,though am wondering why green lead is connected to black on 1 coil and black is connected to green on the other coil?checked voltage on coils while starting and it,s 8.75v .doesn,t sound right to me battery is good all connections ok,dnya s system on the way.tink this could be part of my problem as the bike doesn,t want to rev beyond 5k .i adjusted air screws accordingly leaner on 1 & 2 and richer on 3 & 4 but doesn,t make any difference.
any help apriecated knut

[Pigford]

Knut, posted ignition Friday mate.
If you ran the bike dry, I'd bet the carbs picked up some shite from the tank
As for ignition, I've included the instructions. The coils need a switched positive feed, which is connected to one of the coil connections (Dyna coils), don't matter which one you choose, and put a link to one of the other connections in the 2nd coil. The remaining coil connections are connected to each of the feed wires from the Dyna S pick up plate. When you receive my parcel, all will become clear.

http://www.dynaonline.com/english/instr ... -1_2-2.pdf

You may need to set up a fresh live feed & check output.