More carb troubles, engine won't return to idle revs

[Oddjob]

Could be that's the problem, could be a spring under that which has rusted away and not forcing the T cup up enough for it to close the throttle riser.

[McCabe-Thiele (Ted)]

Yep they're all there but one T cup bit in lower end of riser ( one on which brass cap fits) doesn't want to come out and didn't during strip down .

I do not see that as a problem if its the unsprung static cup.

[billdn]

With you on that Ted , also no spring below it.

[McCabe-Thiele (Ted)]

Did you number the sliders & put them back in their original carb body.

[billdn]

No worries Ted on that score, been there before, isn't that what old takeaway dishes are for ? 😉🤣

[McCabe-Thiele (Ted)]

No worries Ted on that score, been there before, isn't that what old takeaway dishes are for ? 😉🤣

Yes indeed - so have you sorted it ?

[billdn]

Not as yet. Got to take my dear lady into hospital for major surgery,  so been a bit preoccupied.  I'll let you know how it goes , the bike, that is, when I get time . 👍

[billdn]

Sorry to return to this but have tried everything suggested to no avail. Watched videos suggested, did Bryan's revised bench sync . Air screw on carbs 1 and half turns out but still same problem. 
Any more ideas, close to scrapping b****y thing. Even rechecked float heights again as per Nurse Julie method and all OK.
Someone suggested balancing carbs but as won't tickover seems to be bit early for that ?

[Sesman]

If the throttles are snapping fully closed, which is very easy to prove, I’d wager somebody else’s pension it’s a pilot jet/pilot jet route partial blockage.

[gary123]

Im the last person to dispense carb advice as its all witchcraft to me, BUT my 500 would not run correctly until everything was on, and nice and tight.
Including the air filter and lid and the proper fuel tank, it did not like my aux tank.

[Nurse Julie]

Bill, I'm down in Crowborough from Wed 23rd November for 5 days. If you haven't made any progress, I don't mind coming over and collecting the carbs, bringing them back to Lincs to check them out for you. But, by what you have checked already, I would really only be going over everything again.

[Nurse Julie]

Just a thought Bill, did you fit the carb to manifold stubs in the correct orientation?  If yours are OEM, if they are fitted correctly, they should read 1,2,3,4 from left to right whilst sitting on bike. The 2 middle ones, 2 & 3 are angled differently than 1 & 4, if not fitted correctly, air may be getting in.

[billdn]

If the throttles are snapping fully closed, which is very easy to prove, I’d not somebody else’s pension it’s a pilot jet/pilot jet route partial blockage.

I'm taking them off ...again so I'll have a check but all were cleaned before reassembly but you never know 👍

[billdn]

Just a thought Bill, did you fit the carb to manifold stubs in the correct orientation?  If yours are OEM, if they are fitted correctly, they should read 1,2,3,4 from left to right whilst sitting on bike. The 2 middle ones, 2 & 3 are angled differently than 1 & 4, if not fitted correctly, air may be getting in.

I do remember checking that as they have a number embossed on them I recall.  Have tried spraying them when running with carb cleaner and no pick up in revs. Thanks for the offer Julie, I'll persist in the meantime but if without success, may well take you up on your offer. 👍

[Scottish Badger]

I've just finished rebuilding a spare set of carbs on the bench, here's my thoughts based on what I found whilst setting them up "static".
If you don't screw all the linkage balancing adjusters in far enough, the throttle slides can be held ever so slightly open.  Also, the butterfly stop bolt can be set wrong and prevent the carbs closing off fully - with the throttle fully closed there should be a gap between the butterfly and the eccentric stop pin.
Having said that, revs hanging up on closing the throttle used to be a classic symptom of an inlet air leak somewhere....  but if you're convinced there are no leaks, I'd try screwing the balance adjusters all in by the same amount, say two complete turns? You may have to readjust the fully-open throttle stop afterwards, to achieve full throttle, without the slides rising up beyond the carb bores. Hope this is of some help.....