Slow Returning to Idle
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- vfrman
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- Bike owned: NC30, 1098s
- Location: Layton, Utah, USA
Re: Slow Returning to Idle
OP said they did fit new rubbers.
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Re: Slow Returning to Idle
My carbs are back off, I've given the linkages a good dose of WD40 to cover that base in the event they where not lubricated after cleaning. Checked the throttle cable routing and there's plenty of slack.
My slides seem to be moving freely. I've hooked up the vaccum gauges so will plan on reinstalling the carbs tomorrow and see what's what in regards to individual carb performance.
I do agree its related to a lean mixture but I can't understand why. I've new carb rubbers and the carbs are for my seated within them
The only non standard internals are a set of RO needles.
I'll see what the gauges show and report back, at least they may point me in the right location.
Thanks everyone.
My slides seem to be moving freely. I've hooked up the vaccum gauges so will plan on reinstalling the carbs tomorrow and see what's what in regards to individual carb performance.
I do agree its related to a lean mixture but I can't understand why. I've new carb rubbers and the carbs are for my seated within them

The only non standard internals are a set of RO needles.
I'll see what the gauges show and report back, at least they may point me in the right location.
Thanks everyone.
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- Moderators
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- Joined: Fri Jul 04, 2008 1:01 pm
- Bike owned: CBR954
Re: Slow Returning to Idle
Ah cool this threads a bit big to read.vfrman wrote:OP said they did fit new rubbers.
Now...
Are the new rubbers on properly and sealing right.. not too loose OR too tight? I had some rubbers fitted to my 30 that werent on properly.. couldnt really tell until after a few days...
Ideally you want two people for this.. but when its being slow to retuen to idle spray brake cleaner or something flammable around the carb rubbers and look for it being sucked in.. it should also change the engine idle back down quicker as its replacing the air. This will tell you if you have a leak on the rubbers.
Neeldes won't affect that...
Did you mess with your pilot screws?
Are you vaccum blanking screws in?
xivlia wrote:i dont go fast on this bike so really do not need a rear brake.. /
vic-vtrvfr wrote:Ask xivlia for help, he's tackled just about every problem u could think of...
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Re: Slow Returning to Idle
Make sure your fuel petcock vacuum diaphragm is not passing air...
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Re: Slow Returning to Idle
How does one check the fuel vacuum isn't passing air? Spray carb cleaner on it as well? As that would make sense in my case with cylinder 3. I've spayed cleaner around the carb rubber with no changes, so assume they are sealing right? They are solid on the engine and the carbs are firmly seated. Not a bad idea to order some rick o ones possibly though, mine were from eBay, possibly cheap? Not sure about the op's new ones?
Neo -
Neo -
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Re: Slow Returning to Idle
Take the hose off of the cylinder side (other side still connected to the fuel cock) and suck into it...if you can't suck air through it you are good... If you can you have a problem. Honda makes a low cost kit to repair.
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Re: Slow Returning to Idle
Isnt sucking on the line creating a vaccume so it will therefore open the fuel tap?
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- Settled in member
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Re: Slow Returning to Idle
OK,
Had the bike fired up this morning with the guages on. Was impossible to balance the carbs because although the throttle was snapping shut the actual throttle cam wasnt snapping shut all the way ( even when the idle adjuster screw was wound back out of the way).
The linkages have been heavily coated in wd40 but the problem may lie with a sticking throttle cam.
Can this be removed or where am I not managing to get lubrication to?!
Had the bike fired up this morning with the guages on. Was impossible to balance the carbs because although the throttle was snapping shut the actual throttle cam wasnt snapping shut all the way ( even when the idle adjuster screw was wound back out of the way).
The linkages have been heavily coated in wd40 but the problem may lie with a sticking throttle cam.
Can this be removed or where am I not managing to get lubrication to?!
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- Familiar Member
- Posts: 331
- Joined: Wed Nov 27, 2013 6:45 am
Re: Slow Returning to Idle
The diaphragm in the fuel tap should seal - it just pulls slightly with the vacuum pressure to let fuel through on the other side. Correct on it opening the fuel tap though..so maybe do with bike running? (If you think your float valves may not seal
).

- Drunkn Munky
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- Location: Kent
Re: Slow Returning to Idle
you have balanced the carbs wrong then, one of your butterfly's is shutting before no.2 carb (i thinkRascal wrote:the actual throttle cam wasnt snapping shut all the way ( even when the idle adjuster screw was wound back out of the way).
