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Hanging idle please help

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Wenman:

--- Quote from: jeremypeachey on July 13, 2020, 06:21:58 PM ---Is it possible for the return spring to bind in its shroud (if it has one )?
[/quote

Great idea and on reading this I got very excited to think it might be something simple as that however as previously mentioned it dosent do the fault when engines off and if it was the shroud I’d expect it to do so both engine running and engine off??

Because it fails to do so when off I don’t believe it’s anything mechanical?

Could be wrong tho, have been many times before!
--- End quote ---

Wenman:
Okay so this morning I removed the cables from the carbs ran it and still playing up, then I also removed the pod filters to see if they causing the issue.

Still defective

It seems no matter what I do when I open the throttle slowly raising the lifters only about 5mm they will NOT seat back quickly.

I have done another video which shows the slides themselves very slowly returning to where they should be.

https://youtu.be/yKIJlmy-rHc

Please have a look and see what u think?

Is there anyway of raising the sliders so they don’t go down as far as they do when they slow down by screwing the idle screw in raising the idle but then somehow reduce the idle on the air/fuel screws.

I’m running out of ideas now 😩

K2-K6:

--- Quote from: K2-K6 on July 13, 2020, 05:33:47 PM ---Ok,  in that direction of "oddness" what have you ended up at when setting the idle mixture screws?

Projection to try and see if if makes a difference,  turn the mixture screws IN a quarter turn from where they are,  this should slow the tickover down ( makes it richer) forcing you to wind up the main tickover rpm control for the carb rack to bring it back up to normal level.

Let us know if that changes it.

--- End quote ---

The routine I posted a couple back is trying to move it in the direction you are after,  give that a try and see if you get an improvement to assess if it's on the right track.

blackeagles:

--- Quote from: Wenman on July 12, 2020, 01:20:09 PM ---
The only thing I can think of is an air leak in the inlet rubbers but when I had the carbs off I inspected them all and they all looked good??

Don’t really want to start throwing money at it when I don’t know what the exact problem is?

Any more help would be appreciated if you guys/girls have any ideas??

Thanks

Alan

--- End quote ---

this is what i said when i was having the initial problems with my pd42a carb setting (not quite sorted yet).  even spraying carb cleaner/ether on them didn't raise the revs (but took the paint off the brace) but k2-k6 suggested i get my wallet out and i replaced the lot (i didn't realise the 'stacks' in the cleaner are tapered so act a velocity stacks) anyway at least it now runs and when, like you, i sort out the sync and pilot setting it should be all good.

Wenman:
Right so carbs off.. slides out all cleaned reassembled, slides move and fall freely off the bike, there is zero friction on the sliders, return spring added and they slam shut.

They still very slowly drop when I apply a very small amount of throttle.. this is def being caused by the engine running, maybe it’s characteristics??

Please if anyone has a CB750 can they try running it apply a small amount of throttle and watch how fast the sliders seat?

Maybe I’m just going mad!

Thanks you

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