Clear tube float adjustment on 29mm

The VM26's have a better idle circuit then the VM29's.
The 26's will have a stronger idle signal then the 29's therefore
don't need as much idle fuel.
The VM29's being ment as a race carb idle quality was not high on the list.

Ok
Still going to try them out
Thx

Sorry I ment to say the 26's will not need as big a pilot jet
as the 29's because the stronger signal will draw the same
amount of fuel thru a smaller jet.

happy times.....got new valve gasket , change out pilot jets from #25 to #17.5.
Idles perfect at 1600 and does not die out anymore.
only thing... can not lower idle...seems like the slides on the 29mm are lower then the 26mm.
can it be that the compresson from the 1198cc kit and 420 lift cams are setting the idle/
compresson is between 150 and 160..warm..open throttle.

spdygon wrote: ...Idles perfect at 1600 and does not die out anymore.
only thing... can not lower idle....

Failure of the idle thrumb screw to sufficiently reduce idle rpm, may result from a bench-sync error where the thrumb screw wasn't positioned so as to allow further lowering of the throttle slides below the arbitrary initial slide height settings.

One method is to have the thumb screw in about the middle of its thread during the bench sync.

Good Fortune!

Patton.....
Which is the idle thumb screw ......do u mean the one u turn to rise or lower the idle?
Or is it inside the carbs?
Thx
Just came to me......u mean turn the screw in half way...then Sync the carbs
And adjust rpm.
Awesome
Thx Again

spdygon wrote: Patton.....
Which is the idle thumb screw ......do u mean the one u turn to rise or lower the idle?
Or is it inside the carbs?
Thx

The screw that's turned by hand to raise or lower the idle speed by raising or lowering all the throttle slides simultaneously.

Good Fortune!

Patton....
No luck...tried your suggestion. Turn the idle screw in half way then syncronize the carbs, idle was at 2500rpm.
Then turn the idle screw out and only idle down to 1500 , 1600 rpm.
Got another suggestion.....I also read my manuel but carbs are not the sameas the one on the Manuel.
thx

If there's space between tip of thumb screw and carb's closed throttle stop, the throttle slides are for whatever reason not lowering enough.

The way it's supposed to work is that the thumb screw may keep being turned out producing progressively lower rpm until the engine dies.

Would next examine the throttle cable and its connections to determine whether the throttle cable is hanging so as to disallow full throttle slide closure, or whether the throttle cable adjustment at the carb is too tight and needs more slack.

Another test would be to manually assist the return spring by pressing the throttle cables to closed position in order to see whether there's some resistance to full closure that's not being overcome by the return spring.

Yet another test would be to rule out throttle cable/adjustment issues by disconnecting the throttle cable at the carbs to determine if the same too high idle issue persists.

If determined that the issue (insufficiently closing throttle slides) isn't related to the throttle cable or throttle cable adjustment, it's back to square one as to why the throttle slides aren't sufficiently lowering.

As known, when the throttle slides are able to keep lowering, rpm will continue to lessen until the engine dies.

Good Fortune!

spdygon wrote: Patton....
No luck...tried your suggestion. Turn the idle screw in half way then syncronize the carbs, idle was at 2500rpm.
Then turn the idle screw out and only idle down to 1500 , 1600 rpm.
Got another suggestion.....I also read my manuel but carbs are not the sameas the one on the Manuel.
thx

The correct idle thumb screw setting must be made with carbs on the work-bench before bench sync. And left in the same position during the bench sync. And still be in the same position after completion of the bench sync. All while the carbs are in-hand on the workbench.

With carbs fully assembled, and in hand on the workbench, turning the thumb screw further out should lower the throttle slides to their fully closed position.

Ability to fully close the throttle slides should be verified before attaching the carbs to the engine.

Good Fortune!

I see......will try that
Thx

finally fix......as metion before. i ordered a carb repair kit from z1parts.net for my 26mm.
was able to work all o-rings in place ( being they were little over size ) except for the choke plunger o-ring. those were to big so i had left them out as they seem not to bad.
Patton suggest to bench sync...so decided to do that again with same result. today i stop by ace hardware and match 4 new o-ring.
and that fix the problem....idle fully adjustable from 0 rpm up to about 4k rpm.
i called z1 last week and left a message with no return call yet....so i email them yesterday with pics and no responce yet.
Pic are the choke o-ring..left original and right is new