TOPIC:

Bike is a 1980 kz1000 z1 Classic. I've just finished converting it from fuel injection to carbs, and I'm having trouble tuning it to idle well.

Some basic info...

Carbs are vm28 with accelerator pump.
-15 pilot
-102.5 main
-Jet needles are 5CN29 (non-adjustable, 1 clip)
-Float heights set to spec (4mm +/- 1)
-K&N individual pods
-Stock 4-into-2 exhaust
-Accelerator pump rod set at factory spec of 4mm length
-Idle speed screw set at 2mm gap from carb mounting bracket before bench sync performed (per factory manual)
-Pilot air screws set to 1 1/4 turns out as starting point.
-Slides bench synced at 1mm gap

Carbs have just been thoroughly cleaned with soak, brake cleaner, tiny brushes and compressed air. All passageways clear. Slides move freely. New rubber manifolds held tightly with band clamps, no air leaks found anywhere on setup. New spark plugs and caps, plug gaps set to oem spec of 0.8mm.

With this setup I should be able to achieve a stable idle, right? I expect that I might have to rejet for the pods once I begin riding her, but I thought the current jetting would at least allow an idle. Is this current setup acceptable as a starting point?

Cylinders 3 and 4 sound good, steady firm "pop" out of the exhaust, no rich fuel smell. 1 and 2 are weak, "whispy", and at least one of them is sneezing though I can't tell which.

Basically, I need recommendations for starting points on all adjustments and some advice for dialing into stable idle from those points.

Anybody got a minute?

P.S. Beautiful bike, engine sounds good and strong. Can't wait to ride her!

I would go to 17.5 pilot jets and 105 mains.

17.5 on the pilots...do you think my current pilots could be preventing me from getting the idle? I was thinking they wouldn't have a major effect until I start moving (stable air environment around a sitting bike).

I've got some 105's, will have to check jets r us for pilots.

Any advice for dialing in with my air screws? Should I leave the sync adjustment alone while tuning?

aphex wrote: 17.5 on the pilots...do you think my current pilots could be preventing me from getting the idle? I was thinking they wouldn't have a major effect until I start moving (stable air environment around a sitting bike).

I've got some 105's, will have to check jets r us for pilots.

Any advice for dialing in with my air screws? Should I leave the sync adjustment alone while tuning?

Yes. They are probably plugged or the ports in the bodies are.
No, of course they do.
No....
Mechanical static sync first.
The FSM, factory service manual, has all that info in it, including a chart showing how the carbs flow fuel and air at different slide openings, what the 3 or 4 circuits do and respect to the different circuit overlaps.
Do you have one for this carb setup?
I can not stress how important it is to get one and actually read it.....
All these questions have been addressed many many times on this and other sites.
Sometimes you have to suck it up and do a little reading/learning with the FSM! LOL

sorry duplicate

1 ½ turns out on the pilot air screws seems a bit lean. I know it’s not the same bike, but on a Z1300 you start with the screws 3 turns out.

Thanks for the responses, guys... I can't stand it when someone asks a simple question that could easily be answered with a little research, so I try not to be "that guy".

I have spent a month or more rummaging through the internet and factory manuals for 3 different models of KZ, and I still haven't found what I'm looking for. I'll keep looking.

I dont think there is an fsm for this bike with carbs lmao

How could there be?

Exactly! This is why I posted on the forum.

My manual says nothing about carbs, the manual for my carbs says nothing about pods (or much about tuning in general for that matter...the vm28 pumpers weren't meant to be messed with because of emissions control), and internet searches have brought up nothing about tuning these carbs on this bike with pods AND stock exhaust. Lots about LTD's with Kerker's, though.

Most guys seem to run 26's with aftermarket exhaust on the Z1 Classic. Some valuable info reading about them, but not quite what I need.

I will try following the general rule of thumb regarding stage changes for pods and go from there. I expect that since my carbs were jetted lean and given accel pumps (and since I'm on stock exhaust) I won't have the same results as most do when running non-pumpers with aftermarket pipes. Was just trying to get some opinions on ways to tackle that issue.

Ok I'm using 26mm in my KZ1000, pod filters and 4:1 headers with a low restriction baffle board, 115-117.5 mains, 17.5-20 pilot jets, stocks needle clip position and idle mixture screws at abou 1.25 turns out.