gx200 20mm carb?

[clonejunkie]

I was wondering if a 20mm throttle bore gx200 carbs are rare, all the ones I ever had were 17.80

 

[clonejunkie]

not sure if its an oem Honda it says huayi p19 and I think my old predator had a huayi on it but it wasn't 20mm ???
:shrug:

 

[mipowdercoater]

stock bore on the gx390 is 21mm so I would say its off a clone gx340-390.

 

[clonejunkie]

thanks for the reply maybe I measured it wrong because it bolted right up to my 212 predator and it added more power than any mod ive done so far. he gave me the specs on it 670 venture ,140 e tube ,95 main jet, .22 idle jet . 20mm throttle bore. I have the black mamba jr cam , 14cc head , the cheap 1.3 rocker arms, 26lbs springs, nrracing stage 1 kit and billet flywheel and it felt like this carb added around 2hp over my stock one. gonna try to post pics of it

 

[clonejunkie]

got it from a flea market

 

[Dragbikemini]

Thats cool! looks like a decent polish job. Measure bore on the other end. would like to see pics of the other end. Thats a decent clone carb BTW. made in japan.

 

[mteezey]

Imo I would rough up the inside of the carb a little. I don't think you will see any gains from having it blinged out like that. Now if you do the outside like that it would look real cool.

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[David wulf]

Imo I would rough up the inside of the carb a little. I don't think you will see any gains from having it blinged out like that. Now if you do the outside like that it would look real cool.

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You are correct . It will actually hurt flow being polished like that . Exhaust ports are the only thing that could use that type of finish .

But it does look nice , to bad he didn't do the outside instead of wasting his time on the inside .

 

[clonejunkie]

I'm gonna take it off and measure it when I get home. I know your not supposed to polish the intake on the head but the first half of the Carb doesn't really see gas and the second half where the butterfly is came polished from the factory I'll take a pic of the back of it.

 

[Prowler08]

Why would you not want the carb polished like that?
The intake port no, the carb yes! The air and gas mix in the intake port.
The less turbulence you get through the carb the better...smooth and shines is good!

 

[clonejunkie]

That's what I was thinking . The back half came polished where the butterfly is so I figured do the rest so its all smooth. Me and my brother both have the bmj cam only thing different is he has a 22 mikuni and fuel pump . I could never catch him now from a dead stop I smoke him now by a lot lol

 

[65ShelbyClone]

The fine turbulence caused by the surface finish in the carburetor isn't detrimental in any measurable way. Laminar flow doesn't promote fuel-air mixing and the most restrictive part of the carburetor is the venturi anyway.

Thats a decent clone carb BTW. made in japan.

It doesn't say "made" in Japan, it says designed in Japan. That is because it is a Chinese-made Chinese copy of a Japanese Keihin. Honda gets all their carburetors from Keihin and as has for decades. You won't find anything else on a real Honda. Keihin even supplies the EFI for Honda's bikes.

 

[clonejunkie]

Thanks for the info guys. Don't know if the polish job helped performance but this Carb added power that I can actually feel.

 

[FirePowerMinis]

670 venture

.670 x 25.4 (inch-mm conversion) = <20