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Hanging idle please help

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Wenman:
Okay so here’s the problem..

Honda CB750 k2
Stock carbs
Pod filters (don’t kill me)
4-1 (again don’t kill me)
Standard idle jet
+4 on the main jet
Toming correct
Cam chain correct
New coils
New leads
New plugs
New points
New condensers

Bike runs okay, pulls well above 2500rpm suggesting the main jet is okay, really bad idle and running very rich so I put the stock idle jets back on.

The main issue I am getting is the revs hang around 2500/3000 rpm when at a stand still.

I’ve put them on a vacuum balancer which was impossible as I’m struggling to get the bike to run at idle.

Everything seems okay on the carbs, they were fully dismantled cleaned new jets, seals, float heights done etc.

The throttle return spring is new and if anything on the heavy side.. after holding the throttle open for 3 miles of 50mph my hand was hurting 😂

If I apply A downward pressure to the tops of the carb lifters and blip the throttle it returns quickly to idle every time .. Almost like Ive made an error when putting them back together?
It feels like they are not closing properly?

I know this could be a multitude of things but was wondering if anyone has experienced this and it was a stupid error made when putting a set of these carbs back together??

Thanks for your help

Alan

Johnwebley:
Have you air leaks between carbs and head?


Try removing the pods and checking.

You could see if the slides are dropping correctly.




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Wenman:
I’ve sprayed the inlet rubbers with carb cleaner and didn’t notice any increase in rpms?

Also slides are all seating correctly I believe?

Thanks tho

K2-K6:
Do you have both throttle cables fitted?

If so,  can you bring the idle down by "forcing " the twist grip closed?  ie. Rotating it clock wise to make the secondary cable work.

If it closes off the high revs by doing the above,  have you tensioned the normal throttle  cable adjustment too much as it should have about 10 degrees of rotational slack at the twist grip.  This would also make the throttle really heavy too if it's not set correctly.

Wenman:

--- Quote from: K2-K6 on July 03, 2020, 05:01:49 PM ---Do you have both throttle cables fitted?

If so,  can you bring the idle down by "forcing " the twist grip closed?  ie. Rotating it clock wise to make the secondary cable work.

If it closes off the high revs by doing the above,  have you tensioned the normal throttle  cable adjustment too much as it should have about 10 degrees of rotational slack at the twist grip.  This would also make the throttle really heavy too if it's not set correctly.

--- End quote ---

Pushing the throttle grip forward does not reduce the revs sadly...


I def have play about 10 degrees at the throttle grip. I can see a small amount of slack in the ‘pull’ cable at the carb rack but unsure on the ‘push’ cable? I’ll have a look

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