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 Post subject: CV carb ?
PostPosted: Sat Oct 24, 2020 8:08 pm 
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Joined: Tue May 05, 2009 8:00 pm
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Current ride: X1 2001
Location: southampton
so am i right in thinking , in a CV carb , the pilot jet is the starting circuit
mixture adjustment.
then the main jet size & needle hight are the running mixture adjustment ?


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 Post subject: Re: CV carb ?
PostPosted: Sun Oct 25, 2020 11:39 am 
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Location: Oswestry
The needle profile, height and needle jet will have more influence over mid range running than the mainjet.

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 Post subject: Re: CV carb ?
PostPosted: Sun Oct 25, 2020 11:45 am 
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It's been a long time since I binned my CV and fitted a Mikuni, so I'm not certain if the idle adjustment is done off an airscrew or a fuel screw. Generally, if it's on the atmosphere side of the slide, it's an airscrew, if it's on the intake side of the slide then it's usually a fuel screw. Check the needle and needle jet for wear, I've had aftermarket ones wear surprisingly fast.

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 Post subject: Re: CV carb ?
PostPosted: Sun Oct 25, 2020 1:02 pm 
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Current ride: X1 2001
Location: southampton
cheers Adam :yup:

fuckin scooters :headbang:
trying to get it back to standard , to get it running right.
standard air box etc , just to commute on tbh.
it had been overjetted to compensate for a crap cone filter , had some mickey mouse spark plug in it 15mm too short compared to standard plug , surprised it ever ran
unsure if it's a standard needle , may buy one just to rule it out too

running so rich it's fouling the plug on a 4 stroke :shock:
:headbang:


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 Post subject: Re: CV carb ?
PostPosted: Sun Oct 25, 2020 2:24 pm 
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Current ride: Buell 1125R
Hi Nutah'
Bit boring to begin with but he gets to it eventually (It's a good article re Carburation).
https://www.cycleworld.com/story/bikes/ ... rburetors/

All the best.

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 Post subject: Re: CV carb ?
PostPosted: Sun Oct 25, 2020 7:02 pm 
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Joined: Fri May 08, 2009 1:13 pm
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Current ride: XB9SX
Try understanding a Yam SRX 4V single with a ‘concentric’ on the left inlet valve and a ‘CV’ on the right inlet. :? Just poured Reddex injector cleaner in mine to clear the gunk. Seemed to work ok after. 8-)

You could try calling ‘Ital Scooters’ here in Cheltenham on 01242-255200. I don’t know the proprietor personally, but l think he does up oldies like yours Nutah and might just give you the right tips over the phone. ;)


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 Post subject: Re: CV carb ?
PostPosted: Sun Oct 25, 2020 9:58 pm 
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cheers boys , yeh i have been youtubing quite a bit
unfortunatly I have swapped over so many parts chasing running & starting problems
I have lost myself , should have stuck to changing one bit at a time....
I am doing my head in :headbang:

I have done away with all the modified crap , back to standard
coil , plug , air box , carb cleaned , jets all back to standard , clear of crud
just unsure if the needle is standard...
we shall see , if it ever stops fucking raining :roll:
still back on shift again so bollocks to it for a while :coat:


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 Post subject: Re: CV carb ?
PostPosted: Mon Oct 26, 2020 11:02 am 
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If that your problem and someone has been mucking around with it, check your float height too. They're usually adjustable by bending tangs etc on the bit that locates the float needle.

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 Post subject: Re: CV carb ?
PostPosted: Mon Oct 26, 2020 12:14 pm 
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:yup: cheers Adam


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 Post subject: Re: CV carb ?
PostPosted: Sun Nov 01, 2020 6:41 pm 
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mmm :?
so started ok , but revs still pick up for a while then drop back ..which i would suspect an air leak
yet spraying inlet manifold with WD40 made no difference :headbang:

then it starts pissing with rain yet again....needs another shed :old:


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 Post subject: Re: CV carb ?
PostPosted: Mon Nov 02, 2020 10:33 am 
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Is the diaphragm in the CV leaking not allowing the slide to rise. I had this on a DR 400 dirt bike once.

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 Post subject: Re: CV carb ?
PostPosted: Mon Nov 02, 2020 5:39 pm 
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diaphragm seems intact Adam , you can lift the slide with your finger & there is the vacuum effect
as it lowers
i always reasemble them in a mid position ,then check operation of it.

convinced i have a blocked hole in the carb body , as i have cleaned the jets , will have to strip it again....
as the needle is at it's lowest adjustment , then took the air filter inlet elbow off &
yet it's still running sooty rich on the plug :headbang:
:headbang:

runs ok apart from low throttle when it is fluffy so rich to my thinking :?
wondering if it's the pilot jet hole in the body of the carb :coat:


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 Post subject: Re: CV carb ?
PostPosted: Mon Nov 02, 2020 8:29 pm 
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Current ride: Buell ulysses
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has somebody been in there and drilled it out bigger :idea: :headbang:

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 Post subject: Re: CV carb ?
PostPosted: Mon Nov 02, 2020 9:04 pm 
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Location: southampton
:shock: I hope not , a carb would cost more than the scooter did :headbang:


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 Post subject: Re: CV carb ?
PostPosted: Tue Nov 03, 2020 5:59 pm 
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stripped the carb , blew through the carb body found some small chunks of plastic & under the float needle :headbang: , cleaned it all out jets etc. again... guessing its the cause of holding the float up flooding making it run rich :roll: probably have to adjust the needle hight again if this leans it off
so i will fit an inline filter , stick it back on & see


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