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Thread: Keihin cvk 40 issues

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    A Bit Bored mala's Avatar
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    Default Keihin cvk 40 issues


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    Hoping someone can help.

    Good spark and timing is fine so thinking carb.

    Bike starts runs and ticks over.

    Missfire and hesitates at large throttle openings. (Ok if you feather the power)
    Close the throttle and it takes forever to drop to tickover.

    Quite funny as if you really want to go it won't and if you want to slow down it wont.

    Am thinking it could be one of the 2 diaphragm's or both.

    Help

    its a KLR 600 1985

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    Should Get Out More Julian_Boolean's Avatar
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    Default Re: Keihin cvk 40 issues

    Sounds like you've got an air leak between the carb abd the head, try squirting WD40 over the inlet rubbers whilst it's ticking over, if the engine speed goes up you've got an air leak.
    With a 1985 bike I'd replace the inlet rubbers before doing anything, they're bound to have perished by now.

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    A Bit Bored mala's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by Julian_Boolean View Post
    Sounds like you've got an air leak between the carb abd the head, try squirting WD40 over the inlet rubbers whilst it's ticking over, if the engine speed goes up you've got an air leak.
    With a 1985 bike I'd replace the inlet rubbers before doing anything, they're bound to have perished by now.
    Will try anything easy first before I break out the spanners.

    thanks

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    Should Get Out More Yorick's Avatar
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    Default Re: Keihin cvk 40 issues

    Have you got a reet big 'ammer ?

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    A Bit Bored mala's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by Yorick View Post
    Have you got a reet big 'ammer ?
    Yup.

    Sorted t' leckies owt yistedi wee iit

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    Should Get Out More Yorick's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by mala View Post
    Yup.

    Sorted t' leckies owt yistedi wee iit
    Champion So tha's got a special leccy 'ammer?

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    A Bit Bored mala's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by Yorick View Post
    Champion So tha's got a special leccy 'ammer?
    I was Hammered with an ammeter.
    Did tap the preload up on back shocker as the clever c-spanner things are crap.

    I used to scuba in Lanzarote .
    You have petting sharks.

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    Should Get Out More Yorick's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by mala View Post
    I was Hammered with an ammeter.
    Did tap the preload up on back shocker as the clever c-spanner things are crap.

    I used to scuba in Lanzarote .
    You have petting sharks.
    Great on a BBQ

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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by mala View Post

    I used to scuba in Lanzarote .
    You have petting sharks.
    Sharks that pet you?
    Sounds fishy to me.

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    A Bit Bored mala's Avatar
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    Default Re: Keihin cvk 40 issues

    Bike still spluttering.

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    Should Get Out More maccecht's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by mala View Post
    Bike still spluttering.
    Has the bike sat for a long period? Is this something that has just happened as in the bike was in daily use then it started playing up? If it has sat for a period take the carbs off strip them and soak them in cheap Cola [tesco will do] leave them overnight blow out all the orifices the following day and refit them with factory settings. Done this numerous times and it works most recently on a TDM 850 that had sat for 5 years. Also change your spark plug as this can be overlooked and can cause numerous running issues.

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    A Bit Bored mala's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by maccecht View Post
    Has the bike sat for a long period? Is this something that has just happened as in the bike was in daily use then it started playing up? If it has sat for a period take the carbs off strip them and soak them in cheap Cola [tesco will do] leave them overnight blow out all the orifices the following day and refit them with factory settings. Done this numerous times and it works most recently on a TDM 850 that had sat for 5 years. Also change your spark plug as this can be overlooked and can cause numerous running issues.
    last owner did 1000 miles in 18 years.
    Am going to strip carb this weekend if I can't find anything obvious.
    Normally put cola in the rum but will make the sacrifice in the name of horse power.
    30 quid for a diaphragm will invest in the cola first.

    Ta

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    Should Get Out More maccecht's Avatar
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    Default Re: Keihin cvk 40 issues

    You will probably notice yellow varnish in the float bowls. The drillings in the carbs are very small and block easily. Completely submerge the carb body in a pot or suitable container just big enough to hold it. Dont want to waste coke do we even Tesco 1.50 for 6 tins variety. Note under the pilot screw will be a spring possibly a tiny washer and an O ring dont lose them. Give it 24 hours and give it a shake every so often let us know how you get on. A compressor would be perfect to blow out the drillings after soaking and dont mess up the float level. Check your float needle for a ring mark as it will have gone hard and may let by. A new one would be a good investment

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    Should Get Out More Julian_Boolean's Avatar
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    Default Re: Keihin cvk 40 issues

    30 for a diaphragm is very cheap - I don't know about Keihin CV carbs (I've never had a set apart despite having two bikes with them) but with Mikuni CVs the diaphragm and slide are one part and if you but pattern diaphragms you have to get them glued to the slides.

    It still sounds like an air leak to me, are you running it with the original air box and filter?

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    A Bit Bored mala's Avatar
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    Default Re: Keihin cvk 40 issues

    Quote Originally Posted by Julian_Boolean View Post
    30 for a diaphragm is very cheap - I don't know about Keihin CV carbs (I've never had a set apart despite having two bikes with them) but with Mikuni CVs the diaphragm and slide are one part and if you but pattern diaphragms you have to get them glued to the slides.

    It still sounds like an air leak to me, are you running it with the original air box and filter?
    All original on the air box etc.
    Going to look at manifold and fixings tonight as air leak probably best bet.

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