new SmartCarb SC3 34mm advanced metering rod carb option

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Re: new SmartCarb SC3 34mm advanced metering rod carb option

Post by Nsign »

Chuck78 wrote: 12:28 pm Jun 20 2026 @Nsign / Nathan, I would consider making it a mandatory advisory fitment comment that this Yamaha 2004 WR250F petcock be recommended for the KDX200 E-Series SC3 34mm fitment. It appears this will solve the fuel hose routing interference issue with the SC3 choke knob on the KDX200E.
Certainly happy to look into this but a few questions/clarifications first please.

Is this petcock compatible with and/or required for C or H series bikes? The 220? If not, why not? Different tank geometry/fuel line routing?

Generally we like to include everything necessary in the same box rather than direct customers to order anything separately - either with required items or even recommended ones we make an optional add-on when purchasing. Partzilla and Amazon have it for $50. It's $65 from Yamaha direct. I'm wondering if we can source them at volume through a dealer of ours that is also a Yamaha dealer... If not we can do an outbound link, but that assumes people read the Fitment Information tab on the product page and not everyone does.

Anyway let me know if you would regarding the differences between model series so we can have the most accurate info on our site.
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Re: new SmartCarb SC3 34mm advanced metering rod carb option

Post by Chuck78 »

Nsign wrote: 02:29 pm Jun 20 2026
Chuck78 wrote: 12:28 pm Jun 20 2026 @Nsign / Nathan, I would consider making it a mandatory advisory fitment comment that this Yamaha 2004 WR250F petcock be recommended for the KDX200 E-Series SC3 34mm fitment. It appears this will solve the fuel hose routing interference issue with the SC3 choke knob on the KDX200E.
Certainly happy to look into this but a few questions/clarifications first please.

Is this petcock compatible with and/or required for C or H series bikes? The 220? If not, why not? Different tank geometry/fuel line routing?

Generally we like to include everything necessary in the same box rather than direct customers to order anything separately - either with required items or even recommended ones we make an optional add-on when purchasing. Partzilla and Amazon have it for $50. It's $65 from Yamaha direct. I'm wondering if we can source them at volume through a dealer of ours that is also a Yamaha dealer... If not we can do an outbound link, but that assumes people read the Fitment Information tab on the product page and not everyone does.

Anyway let me know if you would regarding the differences between model series so we can have the most accurate info on our site.
I can't speak on the KDX200C, but I can measure one in the near future or ask my friend to. I actually just missed going to a cookout at his house this evening... That tank shouldn't present any SC3 fitment issues as best as I could tell, due to sitting higer up.




The Yamaha reserve petcocks have the same bolt spacing as the KDX200E & KDX200H/220R tanks, as well as the KX125/250 tanks used in our KDX hybrid builds, but the application varies.






For the KDX200E & for at least 1994-2008 KX125/KDX200-220 hybrids (& likely 2004-2005 KX250F chassis KDX hybrid builds & perhaps later 250F),
the 2004 WR250F
2GU-24500-02-00
https://www.partzilla.com/product/yamah ... 4500-02-00
It looks like based on the pictures in this thread of the E-Series stock petcock fuel line routing vs SC3 choke knob, that the 2001-2006 WR250F/WR400-426-450F petcock is a requirement to have no interference with the fuel hose, although it can be workable with stock, I wouldn't call that a good fitment.

The E-Series center spine frame type fuel tank drapes down to the sides much lower, causing the petcock location issue.
The 1st gen WR###F / 1987+ Banshee / TTR petcock mentioned here sits up tight to the tank, unlike the stock KDX petcock, raising the fuel hose a bit above the SC3 choke knob vs E-Series petcock sitting lower with the fuel hose interfering slightly with the user operating the choke. It is still a similarly configured petcock as stock, but sits much higher, tight up against the tank. Please reference my photos above.



On the KX125/KDX200/220 hybrid builds, the rear-facing horizontal side outlet Banshee / 1st gen WR250F / etc petcock is required due to the KDX engine swap resulting in the KX petcock or KDX petcock on KX tank interfering with the KDX 200/220 intake manifold reed block gasket flange, as the KX tank is much closer to the engine and the KX 125 cylinder is angled forward more. The proximity of tank vs engine/carb is much tighter on these perimeter frame KX125/KDX hybrid builds than the slightly more spacious under-tank area perimeter frame H-Series KDX200 & 220R, so it's mandatory on multiple levels to run this on an SC3 KX125/KDX200-220 hybrid. The KX tank of course needs drilled for the reserve tube as it's an MX tank originally, no reserve petcocks on the KX MX models.





For the KDX220 & KDX200H, the Yamaha bottom outlet (vertical nipple pointed straight down) YZ250X 2016-2022 / YZ125X 2020-2022 / 2-stroke WR250Z 1994-1997 petcock works far better than the stock KDX petcock although it is not required to replace the stock 95-06 KDX petcock, but always recommended as it gives better fuel hose routing and easier carburetor removal clearance and access clearance.
BF1-24500-00-00
https://www.partzilla.com/product/yamah ... 4500-00-00

The WR250F 2004 petcock can also be used on the H series 200 & 220R, but I prefer the vertical bottom outlet 2-stroke YZ250X WR250Z YZ125X version on the '95-'06 200H / 220R. There's more space on the 220R / 200H in this area vs the E-Series 200.



I hope this helps, ask any further questions as needed please.
'97 KDX220R - purple/green! - KLX forks, Lectron, Tubliss
'97 KX125/220R hybrid build! - '25 KX450X suspension, titanium hardware, extensive mods purple/green!
'99 KDX220R project - '98/'01 RM125 suspension, Titanium hardware, Lectron Billetron, Tubliss
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