new SmartCarb SC3 34mm advanced metering rod carb option

[Chuck78]

Chuck - Thanks for the tip on the YZ250X petcock, I just ordered one. Not sure if mine is stock or not.

Nate - I'll get some different angle photos when I get a chance. If I set the carb level the petcock is pointing directly at the choke knob, I angled it down but now the adjuster wheel is impossible to turn because the throttle cable is pushed into it by the fuel tank. I was going to try angling it the other way but I'll use the Yamaha petcock instead. I hope that solves it because otherwise I'm loving the carb.

Here's the 2016-2022 YZ250X / 1990's 2-stroke WR250Z petcock on a 95-06, straight down outlet.



and here's one of the WR250/450 4-stroke petcocks, I believe a more recent model year? Similar to the YZ250X 2016 but horizontal outlet (& I'm not sure exactly what year this is or what model but it hangs down lower than the 2004 WR250F version some have used), several different WR part #'s over the years, but they appear generally the same, early 2000's is cheaper and I'm pretty certain is the one that definitely fits the KDX220/200H tank bolt spacing, most probably do though):



Keep in mind, the E-Series center spine frame tanks hang down much lower on the sides vs the carb. If the YZ250X petcock doesn't work for your E-Series, I need another one for one of my KDX220 tanks, let me know and I'll buy it off of you.

One other thing to note is that the YZ250X petcock does appear to sit very tight up to the tank... Vs the pictured version of the 4-stroke 2000's WR side outlet appears to hang a little bit lower, the body being a little bit longer.

[Chuck78]

I finally installed mine on Saturday and although I still need to dial it in a little, it runs amazing and smooth with great power delivery. I'm happy with the purchase but the fitment has been tricky at best on my 1990. Look where the choke knob sits...


PXL_20260530_180540113 by The Real Guy Photography, on Flickr

2004 WR250F petcock, I wonder if this is any shorter height than the one you have?

YAMAHA OEM FUEL COCK | 2GU-24500-02-00

https://www.partzilla.com/product/yamah ... 4500-02-00

Hopefully that image from partzilla shows up, I just referenced it from their website. Every 5-7 years it seems that the WR petcock part number changed although they all look pretty darn similar on the 4-stroke versions.

[Chuck78]

Here's the 2005 WR250F version, if the 2004 version is slightly taller, which I can't really determine from the angle of that photo, the 2005 version looks to be hugging tight up to the tank, although it's not 52 or $55, it's $71....

Screenshot_20260602-144453~2.jpg (139.93 KiB) Viewed 734 times

Double check to make sure it uses the same gasket to the tank, as that will verify that bolt spacing.

Perhaps trying to find some photographs of actual versions of the 2004 petcock, sold on eBay using seller photos instead of stock default photos, might be a good way to tell if the 2004 version is also tight to the tank like this. It could be that the only difference is the reserve pick up tube height.




EDIT - the 2004 WR version part number is also used on the Banshee through 2006, here's a different photo angle, I also saw a used one on eBay that verified it also sits tight to the tank, so if the side outlet is needed, this one is probably the trick then.

Screenshot_20260602-145141~2.jpg (290.89 KiB) Viewed 734 times

And here's the best photo I could find of the no longer available 1989-1994 KDX200E petcock, granted this is aftermarket, it looks the same as the used ones on eBay that I see that are either missing the fuel nipple that has a habit of falling out (on my H-Series petcicks also !!), or else sitting at a downward 45° facing angle:

Screenshot_20260602-152826~2.jpg (239.76 KiB) Viewed 725 times

So I think that the WR250F 2004 petcock would likely be the best one, maybe we can get you to get one of those on your bike as a test fitter to see if that added clearance keeps the fuel line up high enough above the choke knob?
I can ship one to you if that '16-'22 YZ250X downward facing outlet doesn't work, if you want to ship me the X version once determined.

Sorry to chime in later after the fact of you ordering the 250X petcock, but that one may work out also.

The 2004 WR250F petcock appears to be the best to use both for the E-Series as well as KX125/KDX hybrids, where the 2016 YZ250X seems to be the best to use for the KDX200H/220 tanks.]

[tosaw]

Wow, thanks for all the info! If the one I ordered doesn't work out we'll go from there.

[SpruceItUp]

Hi everyone. I know a lot of you have been waiting on my review of the SC34. Unfortunately life has been extremely busy since I got back from my trip up North with the KDX and I have not really had any time to do anything. Even the bikes have been covered in mud since I got back. They're finally clean as of today.

I'll be honest, I don't have anything negative to say about the SC34 or the team at SmartCarb. It has been a great carburetor so far. It idles amazingly, off throttle performance is great, low end seems better than it was with my Keihin and so on. It has plenty if power with it. It's easy to get dialed in, just by using the knob on top of the carburetor. Fuel milage seems amazing. I went close to 40 miles of riding up in Wellesville Ohio (according to the speedo/odometer on my other bike) and it seemed like it only used a bit over a gallon of fuel from my tank. Maybe a gallon and a half. I don't have exact numbers, that's just eyeballing it, but it used significantly less than the Keihin does. This was slow moving stuff for the most part, though. Not a whole lot of wide open stuff there. So I'm unsure how it would do on gas if you're riding a lot harder on the gas.
The only problems I had were fitment, and now that Nathan worked with me to get that fixed, it has been great.

I'm unsure if the petcock valve in my bike is stock, it seems like it is, but I have not has any issues related to fitment with it and the carburetor. My petcock actually swivels (the part the hose attaches to does) so I can adjust where the hose goes in relation to the carburetor.

If you have any questions please ask, I have taken much too long to post a review and would love to answer any questions you might have as I may not have touched every basis here.

And thanks to Nathan and the rest of the team at SmartCarb, as they have been extremely helpful.

[Chuck78]

I'm unsure if the petcock valve in my bike is stock, it seems like it is.

My petcock actually swivels (the part the hose attaches to does) so I can adjust where the hose goes in relation to the carburetor.

Ahhh... The old swiveling fuel nipple petcock outlet!
This certainly does in fact sound like an OEM Kawasaki petcock, and not for good reasons! That is supposed to be a pressed fit. I learned that the swiveling means it's worn out, by learning the hard way when I couldn't figure out why my boot was covered in gasoline after I had been smelling gas for a little while on the trail. I thought it was a loose fuel line that was poor fitting, so I tried to twist some bailing wire around it with some pliers as a clamp, and the whole nipple came out the back! I jammed it back in there as best as possible, but luckily we were almost at the end of a multi-day trip when that happened 5 hours from home.

Then I got online after I got back from that trip and found other people complaining of the same issue that there is no longer was a press fit and did not fit tightly.

This is literally just a metal to metal press fit, and all cast metal, nothing machined as best as I can tell, which really surprises me that it even fits good enough to seal for 20 years before becoming problematic....

There is no o-ring or packing seal, and nothing to lock it in place both in swivel orientation and just to hold it in place into the petcock. On top of that, it is just a press fit on two different cast the zinc-aluminum pot metal parts, not even a machined smooth precision fit. It amazes me that this was able to seal for so long before problems.

I repaired that one with JB Weld which has to be allowed to cure fully before seeing fuel, cleaning it and gluing it in place as well as a lot of JB Weld on the exterior, but I have not used that petcock in ages since I discovered the Yamaha WR250Z / YZ250X / YZ125X '22& earlier petcock with the downward facing outlet and the four-stroke WR250 & ATV version of that with the horizontal outlet. Although I did have the fuel nipple on one of those come loose as well, but at least that was a machined press fit into the petcock body with a steel tube. That made me realize I really should be putting a bead of JB Weld or similar around the nipples on any of the petcocks.
The Yamaha petcocks are much better quality overall and very low profile compared to the KDX which is a massively tall tower on the '95-'06, with a very problematic fuel nipple design on all years.

[SpruceItUp]

Ahhh... The old swiveling fuel nipple petcock outlet!
This certainly does in fact sound like an OEM Kawasaki petcock, and not for good reasons! That is supposed to be a pressed fit. I learned that the swiveling means it's worn out, by learning the hard way when I couldn't figure out why my boot was covered in gasoline after I had been smelling gas for a little while on the trail. I thought it was a loose fuel line that was poor fitting, so I tried to twist some bailing wire around it with some pliers as a clamp, and the whole nipple came out the back! I jammed it back in there as best as possible, but luckily we were almost at the end of a multi-day trip when that happened 5 hours from home.

I did not know that! Funny thing is it seals perfectly and has for as long as I've had it.
To be safe I'll just buy a Yamaha petcock as you mentioned. Better safe than sorry.
Thanks!

[Tokyotim]

I am not super active here but I picked up a SC3 from Nathan as they are local to me. I will be making some videos of it next week after it’s installed. I am more active on the 3 big KDX Facebook groups you can search Tee Wall and my name will come up. I will try to remember to post some videos here as well. I put them on Facebook and YouTube