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Discussion Starter · #1 ·
Ok i have the quad mods in my signature. i like to drag race, hill climb, ride trails.

i currently have a 39 fcr stock carb. with quick shot bowl, nvqc needle.


I was wondering the advantages of boring my carb to a 41mm......taper vs straight.........or just buy a 41mm aftermarket carb???

i have a big bore, ported n polished, full exhaust, cammod, rev box, fci intake.


thought i might get some gains wth a bigger carb........think the aftermarket ones are ezier to jet on the fly also?????
 

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Discussion Starter · #2 ·
was hoping to get an answer lol. i read all day and asked the dealship today they are getting back to me about price for the stock carb bore.....not sure about straight bore or tapered.....or if i should just buy a 41mm aftermarket carb???
 

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I would look into venom's section on this site and call them to ask opinions. I've read that a bored carb will be a noticeable difference even in a mildly modified machine and yours is beyond that......

I believe they have to modify your FCI to feed into the bigger carb as well....easy from what I read. Ask the pros though.
 

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QUOTE (RockiesYFZ @ Feb 9 2009, 10:54 PM) index.php?act=findpost&pid=744491
I would look into venom's section on this site and call them to ask opinions. I've read that a bored carb will be a noticeable difference even in a mildly modified machine and yours is beyond that......

I believe they have to modify your FCI to feed into the bigger carb as well....easy from what I read. Ask the pros though.[/b]

I agree, Venom just did mine to a tapered 42 I believe.. check it out. Carb wise, its cheaper than getting an aftermarket one, what year is your bike, the 08 has a LOT of adjust ability.
 

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Discussion Starter · #5 ·
its a 2006 yfz 480 big bore. nothing fancy but better then running stock.



whats a price on the carb bore and intake adjsutment? and i live in canada pretty far from venom i would imagine.
 

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Taper bores create velocity and IMO will help with cylinder filling and the velocity will help make jetting easier.

The FCI ring on the carb you have Venom can have it machined to a perfect fit to the new carb bore size, or you can opt to buy their Rat Stack with may work better on the larger bored out carbs as it has more material to remove to match up to the carb's new diameter.

480cc IMO a 42mm taper bored card would be best.
 

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Discussion Starter · #7 ·
perfect thanks terse. was wondering where i would feel the gains of a bigger carb?? or will it be all around the power curve??


i asked venom to pm me on his forum page. hopefully cheaper then what the guys here are doing. canadian performance shops suck IMO.
 

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On your 480cc motor I would expect a gain in power over the whole rpm range. You have a much bigger motor and IMO the carb is to small. Now if you went with a 42mm on a stock bore I've tested and seen the gains to be above 6000rpm.
 

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Discussion Starter · #9 ·
alright so 39mm too small. so u say a 42 mm bore???


do u reccomend aftermarket carb???

or should i get it bored???


tapered or straight bore?? not sure what the difference would be in performance................
 

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QUOTE (Yfz480Rider @ Feb 10 2009, 08:40 PM) index.php?act=findpost&pid=744960
alright so 39mm too small. so u say a 42 mm bore???


do u reccomend aftermarket carb???

or should i get it bored???


tapered or straight bore?? not sure what the difference would be in performance................[/b]

I say go through Venom to have your stock carb bored out to 42mm. and they do taper bore carbs not straight bores.
 
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