z1classic with carbs

Z1class wrote: ...cant turn the choke all the way off either
Only half, but it ran good at all rpms. After warming up it idled at about 3ooo with the thumbwhell all the way out...will a vacuum sync fix....

Carbs won't be right until choke can be closed, otherwise enrichener circuit is always engaged, which prevents the pilot mixture from being properly adjusted. And likely one of the causes for inability to idle at desired 1000 rpm.

A vacuum sync is imo a waste of time unless the carbs are already otherwise in basically perfect condition, and following valve adjustment to specs, new spark plugs, and visual confirmation of fat blue properly timed spark.

Good Fortune!

Ive cleaned the gas tank with b12 and a peice of chain, it has an inline filter and the gas is crystal clear. Valve clearances are all
Between .oo3" and .oo4". Timing is good, advancer is good and free moving, it has a healthy blue spark.
It sat for ten years but the float bowl gaskets and jets look new, main jets are 1o5 and pilots are 15 how does that sound.

Z1class wrote: Ive cleaned the gas tank with b12 and a peice of chain, it has an inline filter and the gas is crystal clear. Valve clearances are all
Between .oo3" and .oo4". Timing is good, advancer is good and free moving, it has a healthy blue spark.
It sat for ten years but the float bowl gaskets and jets look new, main jets are 1o5 and pilots are 15 how does that sound.

Sounds good, and kudos to whoever remembered to drain the float bowls and shut off fuel supply to carbs before storage.

For the record, it's also best to fill the tank before a relatively brief period of expected non-use, or empty it completely before longer term storage

As noted, a proper sync will require first correcting the choke function, so that the choke will fully close, as the choke must be fully closed during sync procedure.
Would suspect this is a mechanical assembly issue in this instance, as opposed to a cleaning issue. And won't hurt to lube the external parts of the choke mechanism.

Good Fortune!

"Thermometer on the exhaust. 1, 3, and 4 were 90 degres and
#2 was 160."

That is not header degrees is it? Even 160 seems way way too low for that. :blink: :blink: :blink: :huh:

May use a tube from the case vent to exit underneath the bike (see pic below).
Some folks attach a small filter to the cap nipple.

The EPA emission stuff (see image below) may be removed and shelved. It doesn't influence carb function.

Vacuum nipples should be plugged (capped) unless used to supply vacuum to the petcock.

The unused hole in air box should also be plugged.

And plug each nipple in the valve cover, or connect them to each other (see image below), or replace the stock covers with the more attractive accessory commercially available non-vented covers.

Good Fortune!

So now after the carb adjustments, I rode about 50 miles
And I could get the choke 3/4 off. If I turn it all the way off
It runs but misfires, and shot off a couple vacuum plugs
On the carb boots. It has to be a carb problem bit I can't
Figure it out. I havent tested the coils yet, only visual but I said
Before it has a healthy blue spark, good timing????? ?

With pods I qould run 17/117 jest minimum. I had the same bike and same carbs. I would rejet, and go through the carbs setting the float heights and bench synching the carbs. Make sure you remove all the air/gas adjustmemts to make sure the passages are not clogged.

You will like that bike. Roy

Does anybody else agree with 17/117 . I said before it sat for ten years but the jets and gaskets look new, the p/o may have changed them he had somebody work on it a couple years ago. But never had it run rite. (i just learned this today) it runs about the same with
Air mix screws from 1 to 2 and 3/4 turns from seated. Would too small jets cause the need fore choke?

Z1class wrote: Anybody still readind this? I got my bike fixed enogh to ride......After warming up it idled at about 3ooo with the thumbwhell all the way out.....

If you're 'idling at 3000rpm with the thumbwheel all the way screwed out' then that is a problem. My KZs will stall when I back out the thumbweel like that.

Now, if you mean 'it idles at 3000rpm with the thumbwheel all the way backed out and the choke is on 1/2 way' then the 3000rpm idle is probably happening due to the choke being on.

But if you really mean 'it idles at 3000rpm' and the choke is off and the thumbwheel is backed out all the way -- sounds like an air leak.

You mentioned "The two outside nipples for the sync tool are hooked together and go to the air valve thats connected to the (exhaust) valve cover. the two inside are hooked together"

-- you might try putting an individual plug on each intake manifold's nipple then block off that hose leading to the air valve (say, with a screw in the end of the hose and a small tie-wrap to cinch the hose around the screw so it's sealed off).

Putting a plug on each nipple on the intake manifolds will eliminate a possible air leak source.

If you get still a 3000rpm idle, try screwing the thumbwheel in enough so you can turn off the choke and still have the bike idling OK. If you can't make the idle work this way, put a nipple on each intake boot and try this.

Can anyone tell me what carbs I have. On the body next to the mount the say Z12 00 and R 63?

post a pic and folks can easy tell

heres a picture of the carbs if it works ( i suck at computers) I have also just capped the emmision
valves on the exhaust, put vacuum caps on all four carb boots, and routed the case breather under the bike, i still have the choke problem.