Revs won't die down.

[floydsz1]

Z1b , carbs cleaned, new jets etc, set on bench then checked with vacuum gauge's.
New inlet rubbers, (sprayed with wd40 when running and no change in revs),
ign timing ok (dyna s),
valve clearances ok apart from number 1 inlet very slightly tight, number 2 inlet very slightly slack.
Tickover is lovely and smooth/quiet,
When cold seems almost ok but when riding or when it's warmed up the revs take a while to die down. Pulls ok when ridden, over say 3,000 rpm all feels ok.
If I turn the tickover down it stalls at junction's etc but still doesn't die down even when riding and pulling clutch in it still holds onto its revs.
Airscrews set at 1 1/2 . I've tried different positions for the airscrews, ie turning out till revs rise then reset the tickover screw etc.
Cable free play set ok.
Beginning to run out of ideas.
Anyone suggest anything please guys.

[z1bman]

slide height adjustment ?

[floydsz1]

slide height adjustment ?

Isn't that vacuum gauge adjustment. Surely that adjusts each slide individually

[z1bman]

no they need to be set to the base setting its all explained in the manual

[floydsz1]

Ok, I think I've got that.
That will be 10mm gap underside of throttle stop or idle screw to bracket.

Then adjust the eccentric bolt/screw that's stops the pulley that the closing cable fits into.

[Z1parR]

Bike is over 40 years old Pete and you're over 50 years old ,
I can see a problem here already

[floydsz1]

Bike is over 40 years old Pete and you're over 50 years old ,
I can see a problem here already

And just what do you mean 🤔
I'm hoping to get it sorted so I can go to jester's rally on it in a couple of weeks.

[Charlie]

Are you absolutely certain that when you stripped the carbs for cleaning that you put the right slides and needles back into the right carb bodies ?

They do wear with each other and can stick if you mix 'em up

[floydsz1]

Wasn't me that actually did them. It was someone on here and what a good job he's done. I've no cause to think he did anything wrong because it was doing it before he cleaned them. It's done it since I bought it a few years ago but it's not been used till I rebuilt it.

[PAULJAC47]

Sounds like its running lean,are you sure no air getting into head rubbers,standard air filter? all jets standard for bike and clip on middle on needle?
floats height set ok?early carbs are a bit of a faff if they the separate ouside adjusters for balance,might be worth re checking,ihave you tried a colurtune?

[floydsz1]

Not tried colourtune yet. Pretty sure no airleaks. Another option is to swop the carbs with the ones on my A4 and see what happens.

[PAULJAC47]

Would defo try a colourtune first,trouble is with swapping carbs is if the head rubbers are a bit old you never seems to be able to get em to seal properly again,sorted out loads of probs with the colourtune,just a thought you say you have dyna s ,it is advancing all the way to the full advance mark past the bob weights and retuning? and has the correct rotor ? not being the early z one?..Paul J

[floydsz1]

Carb rubbers are new. I didn't use any instant gasket but I've sprayed them with wd40 and no change in revs.
I'll try a smear of instant gasket but it did it with the old rubbers.
I'll recheck the ignition but I'm 99.9 % sure it's correct.

Next I'll give the colourtune a go if I can find one round here.
It seems ok when I first start it but as it warms up it then starts acting up.

[PAULJAC47]

If it gets worse when it is hotter....it is too rich, drop your mains and/or needle. If it gets better when it gets hot, it is too lean, do the opposite.try taping up air intake on airbox and see what diff that makes..Good luck Paul J

[floydsz1]

Ok Paul I'll try that. I've a new air cleaner fitted. Did have a k&n but I've put a standard one in and it's the same. I would think the k&n would flow more air compared to the standard one.
Thanks for your help guys, busy day tomorrow by the sounds of it.