Z1OwnersClub GB

returning to this. I cleaned out my carbs and set the throttle to be same in all four bout didn't touch any of the choke parts.

When choke lever is fully up, engine runs at stupidly high rpm 4,000 rpm.

Pushing the lever down maybe a couple of mm drops rpm a bit, maybe to 3,000 then any more than that it stalls.

I am not sure if the idle screw set for correct idling as I was just trying to get the engine warmed up.

does that sound normal?

Why is the choke lever so unlinear? ie. either enginee runs but at 4,000 ish or not run at all?

Is there any adjustment it? or is there some other adjustment that is out?

Can something in in the choke mechanism (jet?) be blocked?

You need to remove the carbs and inspect a few things:

a) Looking into the inlet side of carb down past the air screw is a long
chamber that is towards its end ported of by the choke plunger, this
needs to be clear of any debris. Some early Z1's, as mine was, had a
small felt conical pad inside each of these ports.
b) Check each of the choke plungers is sealing off and air-flow increases
as you open it. just blow down the hole you'll be able to detect the
amount the choke is open.
c) Atomiser tube, remove the float-bowl and you'll see a long Brass tube
extending down into a hole in the float bowl. The hole in the float bowl
and the hole that the tube passes into are linked and must be clear.
d) Atomiser tube has a small jet pressed into the end of the tube, this
needs to be clear and the tube must have no splits along its length.
(FYI, you can pull these tubes out for closer inspection by carfully using
pliers)

There ya go your starter for 10.

Mike

........and they do tend to rev a bit high on start up (3000+ not unusual)