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Sizing bike carbs

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Old Oct 5, 2008 | 01:53 PM
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Default Sizing bike carbs

Is there list anywhere of which bike carbs will run on a standard 2.0 Zetec? I know the usuall zx9r and R1 but the prices on ebay are climbing as this is what everyone uses.

I already have some 95 cbr600 ones but im told becouse these are only 33 or 34mm chokes the 2.0 wont run which is a shame becouse i would have liked to get running on them just so i could wire up the motor a megajolt whilst i get some more sorted
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Old Oct 5, 2008 | 04:06 PM
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It WILL without a shadow of a doubt run, but depends how much power you want as to whether they will be a restriction.
Consider this the 2L Pinto(which is less effecient) used a 26mm and a 27mm choke size to generate it's power(around 100bhp) and could be left on till over 130bhp, why do you think that yours will be too small as you have 4 of them!!
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Old Oct 5, 2008 | 04:39 PM
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Originally Posted by tabetha
It WILL without a shadow of a doubt run, but depends how much power you want as to whether they will be a restriction.
Consider this the 2L Pinto(which is less effecient) used a 26mm and a 27mm choke size to generate it's power(around 100bhp) and could be left on till over 130bhp, why do you think that yours will be too small as you have 4 of them!!
tabetha
I thought they were to small as every search turns up lots of people on forums saying you NEED at least 38mm bike chokes, This is why i asked the question here as you have to take these things with a pinch of salt!!

Im running megajolt and bike carbs and would be happy with 130BHP to start with 150 would be better though

Do you hava a idea/opinion of what is the limit on these carbs

Thanks for the input
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Old Oct 5, 2008 | 04:55 PM
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I would speak to someone like bogg bros, as he does this sort of thing, as a general rule keep as small as you can get away with for the power.
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Old Oct 5, 2008 | 05:06 PM
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Was going to contact bogg brothers but apparantly they don't give too much over the phone lately and i can't blame them as i can imagine how many people have rung with the popularity of bike carbs asking silly questions lol

I might just give it a go, As long as it runs i have nothing to loose and then i will know for sure I would prefer it runs well than big power tbh

Cheers

Danny
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Old Oct 5, 2008 | 05:19 PM
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38mm is enough for 200bhp on the right engine. Jenvey has some technical info on their website about sizing, and that's still a bit bloated.
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Old Oct 5, 2008 | 05:33 PM
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Well Jenvey say,

up to 33BHP - 32mm, up to 39BHP - 35mm (Per Cylinder)

So my 34mm is somewhere between 33BHP and 35BHP per cylinder so in theory it should be able to make around 132-140 BHP if im understanding this right? 140 will do for me and hopefully better throttle control than a larger choke.
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Old Oct 5, 2008 | 08:39 PM
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i was running 40mm kawazaki zzr bike carbs on my williams clio with mild cams that was it and that made 176bhp(150bhp std) thats a 2.0l
my brothers 205 gti ran r1 carbs there also 40mm on a 1.9 so i wouldnt go much below 38mm on a stock 2.0
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Old Oct 5, 2008 | 09:04 PM
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I know what you mean but i only need to make 130bhp like Tabetha said a pinto could run 130 on a single 27mm Choke so im thinking i might try it anyway its good practice and at same time keep my eye out for a ebay bargain lol
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Old Oct 6, 2008 | 05:39 AM
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A 26mm AND a 27 mm choke size, although the person above ran 40mm he maybe did not get to the limit of them.
I can ask me mate who is very versed with tb's if you like, but another that springs to mind is Dave College of Retroford, he had a super quick escort estate making around 280 on 40's(Ithink), was ok till a fuel hose split!!, went onto to do some bloody good times.
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Old Oct 6, 2008 | 06:11 PM
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Cheers that would be good I understand everyone is using 38mm and there going to make more power but everyone running these sizes seem to be doing so because everyone else does if that makes sense. I'm genuinely interested to know what power can be had on smaller carbs now and if they are more / less responsive etc etc

Cheers
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Old Oct 7, 2008 | 04:41 AM
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I'm glad you are on the ball with repsonsive, that is the reason to keep as small as will do the job, the problem is the carbs outer may very well be 38mm but the smallest hole is what makes the size, I used to run 38mm chokes in my 45's for example, so things are not always as they seem, glad someone else noticed the sheep thing!!
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