Carb sliders stuck

[el_oso]

all the carburettor sliders are sticking on. some worse than others and is therfore casuing my idle to be at around 4-5k rpm after riding for any amont of time.
is there anything i can do to keep them from sticking or is it a case of new carbs/sliders?
i have already stripped and cleaned them with some arrow. so i know that they are not dirty.
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[radical]

Sounds like you have a pair of seized/partly seized throotle cables, I doubt if all your carbs would stickat the same time.

[Teflon-Mike]

CV Carbs.
May not be the slides sticking in the body, could be the diagphrams.
Curiouse that they have all gone at teh same time... you'd expect one to start fluttering, then you'ge get progressively worse running, then you'd have a look and find one or two obviousely 'gone' and maybe one pin-holed.
Worth looking at the plumbing... if effecting all four, and asking if you have taken them off to clean or have tried DIY balencing or something.
Bike CV's often not 'damped' like an old car type dash-pot SU CV carb, the diagphram is worked both ways, vacuum above balenced by vacuum below, from pitot tubes either side of the main choke.
some-times externally plumbed. in which case look for perished pipes ariound the carb, or internally.... clogged or firred jets.
Could also be fir in the carb-body, that a spray of carb cleaner wont shift, unless you strip them....
Which is probably the answer.... full carb-strip.

or Doh! Moment... you HAVE stripped them!

Were they that bad before you did?

Did you put them back together properly?

Did you use RTV to get stuff to seal (or not!)

Did you use new gaskets & diagphrams?
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[el_oso]

i know it is not the throttle cables. 100%. first thing i checked.
bike has been sitting for 7months. 2 have freed up nicely. 1 more sticks quite often. the other one seems to stick very occasional.
didn't do a full strip. just took both covers off and cleaned what i could.
RTV? guessing this is a gasket glue. yes this was used. going to check pilots jets as bike has always been a bit of bugger idling, even before it was left for months.
would the carb sliders sticking open be responsible for being difficult to pull away. sometimes have to give it quite a lots of revs (4/5k), otherwise it bogs down for a few seconds and then picks again. another point that may be useful is that sticking seems much less apparent when under load. haven't noticed it sticking open when riding, however when it being revved on it's side stand out of gear tends to stick more often.
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Kickstart]

Hi

On CV carbs the slides are there for the mixture, not the throttle. Hold them all wide open and other than screwing up the mixture it probably shouldn't significantly increase the idle speed.

They might be sticking, but you probably have another issue with the carbs.

If the throttle cables are too tight then it can cause the throttle to stick. Air leaks after the carbs (or on the throttle spindles) can increase the idle speed as well.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Phoenix]

With the aribox off and butterflies open, if you push the slides up with your finger do they all return smoothly? Did you check each diaphragm for holes, cracks or damage to the sealing edge, is the loop in the outer seal in the right place with the diaphragm cover? Made sure the main jets emulsion tubes are clear? Needle might be getting stuck or something and stopping the slide coming down, have you run it with open intakes and actually witnessed the slides getting stuck?

[Phoenix]

As Keith says, if the slide is stuck up but the butterfly closed it's not going to rev at all as no air is getting in, which is why i'm wondering if you have actually seen the slides getting stuck. Have you balanced them?

[el_oso]

i thought it was an air leak at first so that was the first thing i checked for and didn't notice any air loss.
ran it with out the airbox so i know that that the slides are sticking open. even though it may not be causing the main problem with the carbs, it is still a problem. also checked the diapgrams f
i know that the slides are there to adjust the mixture. if they are sticking open surely it would run really lean. have noticed that the bike seems to be running really hot. however it may just be paranoia on my part and the fact that it is an air cooled bike idling at 5/6k rmp on a hot day standing still.
looks like i am completely stripping the carb tomorrow and clean and reset everything.
____________________
Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Kickstart]

[el_oso]

just fully stripped and cleaned out the carbs today. found a dead spider behind my main jet. also cleaned out the air filter and found a load of dust and stoney crap. now running a lot better and is actually rideable. power is there when i give it some gas.
still has the high revving idle problem. also takes ages for the idle to return to normal after revving in neutral. i have checked again for air leaks and still cannot find any. it does only seem to be doing this when the engine is fully warmed up though now. any other ideas people?
edit: managed to get the carb sliders to stop sticking. found some wire wool and some polish and a very tiny tiny film of oil over the plastic sliders did the trick
____________________
Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Kickstart]

Hi

Check the vacuum line for the fuel tap (or vacuum fuel pump if fitted). Also check the throttle cables (possibly try removing the return cable and see if it returns to idle OK without that).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[el_oso]

checked all lines again. all fine.
removed the return line still the same.

warmed the bike up again and then took the tank and air box off. the slides have stuck open again. all four of them stuck halfway. had to take the diaphragm covers off to push them back. they really are very very stiff when warm. when i pushed them back and put the covers back on. i started her up again and everything was fine. normal idle speed. blipped the throttle a tiny bit (2/3k rpm) and reuturned very quickly to around 1k. blipped the throttle a bit more to about 5/6k rpm and the slides stuck open and the revs stayed high and did not return. had to take the covers off again to slide them back as they are too stiff to try and slide back with your fingers.
looks like its time for a new carb
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Phoenix]

What about the springs above the diaphragms, are they the right ones? If it is the slides sticking due to burred sides or something then just get a new set.

[el_oso]

the springs have not changed and they used to work fine.
i think that my carbs have some how become warped as they only stick when warm.
i have polished up the slides with wire wool and polish and while this seemed to work when cold, they slides were not sticking that badly when cold. they were easily pushed back by pressing on them and using the friction of my fingers. when warm they are not easily pushed back.
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Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[Kickstart]

Hi

With the FZ the only thing I could think was that the carb slides were made from a material that had reacted with something over time. They appeared to be some kind of nylon like plastic.

See how much new slides are on their own. If not all of the slides are sticking then swap them round and see if the one that sticks moves with the slide of stays with the carb body (remember that the needles might be different between cylinders).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing