new SmartCarb SC3 34mm advanced metering rod carb option

[SpruceItUp]

I got an email that my Smart Carb shipped out today.

Excited!

I also got an email from Panthera stating my E start kit is being put together this week.
Looks like I've got my work cut out for me.

[Chuck78]

Official announcement, from Nathan Dyess of SmartCarb, just out!

[SpruceItUp]

Well, my SmartCarb just came in the mail! It seems to have plenty of documentation within, thankfully. Along with their base settings that they shipped the carburetor with.
It also ships with 4 stickers and a fuel filter.

Can't wait to give it a try. Unfortunately, I don't think I have any time to tinker with it tonight.

It seems built pretty well as I can tell. The machining seems very well done.

It does seem heavier than my Lectron, possibly because of the aluminum float bowl in comparison to Lectron's plastic. Definitely heavier than the standard Keihin. Though this is all off the top of my head, so feel free to correct.

Overall it seems well built. I'll have to get it in the bike tomorrow and see how it runs!

[Nsign]

Well, my SmartCarb just came in the mail!

Yep, we began shipping KDX orders in earnest earlier this week. The rest of you here with orders in should be seeing your SC3s shortly.

Keep us all posted with your feedback, findings, results, feelings, and profound thoughts and be sure to reach out to us at SmartCarb Fuel Systems if you have any questions about installation or tuning.

As for the heft, well, we always say that the SmartCarb pulls its own weight and then some in performance. The overall unibody X/Y profile is bigger (and thus heavier) to accommodate a full-size float system. Gives the carb big hips as we joke around here but if you look at the stock PWK35 it makes sense. That carb is more float bowl than it is anything else. Why Lectron continues to insist on using undersized floats in their carbs is beyond me. In any case those engineers in Japan that designed the oddity that is the PWK35 knew what they were doing with the float system and so do we.

Cheers!

[SpruceItUp]

Hello, Nathan!
It got here quick! Surprised me.

I'll definitely keep you and the forum posted on my results. I'm excited to see how it performs, I have no doubt in my mind that you guys have made a great carburetor. Especially with how vocal you guys seem to be with the community. It shows me that you really seem to take pride in the product that you have made, as you should.

As for the heft, personally I don't mind haha. If I have to add some weight for a better experience then so be it. Though to be honest, I doubt it is that much heavier than the Lectron in total, and it is pretty much right in the center of mass. Also, I prefer an aluminum float bowl over the plastic that Lectron uses without a doubt, it's just more confidence inspiring to me long term. And as you said, you have your reasons for having a bigger float bowl to begin with.

Thanks!

[Chuck78]

I have no doubt in my mind that you guys have made a great carburetor. Especially with how vocal you guys seem to be with the community. It shows me that you really seem to take pride in the product that you have made, as you should.

Thanks!

I took serious note of that as well... 2 years or more ago when I first reached out to both Lectron and SmartCarb about fitment for our bikes not being listed whatsoever, and asking if I could work with them to investigate what it'd take to fit, Lectron were immediately dismissive despite their Billetron Pro Series published dimensions looking like a far better fit than their actual published fitment of the older style legacy Lectron PowerJet 34mm carbs listed for our bikes. They were pushing me to pay full price for a Billetron Mini for say a KX100 etc 2-stroke, and machine adapters to increase the spigot and airbox bell sizes to fit the KDX, citing that it would have incredible low end power and throttle response... No Thanks, maybe on a trials-like engine build, but not an all purpose KDX.

I had to reach out to their Lead Fuel Systems Engineer at the time, Matt Denecke, outside of Lectron, to actually speak to someone who was incredibly helpful and actually took my word as being legitimate when I said the dimensions look like a pretty great fit vs the older style Lectron PowerJet carbs.... This is the only reason Lectron now sells the Billetron Pro Series for the KDX, all the customer service staff were highly dismissive of my requests...

SmartCarb on the other hand were incredibly warm and welcoming, pleasant to converse with, lending an open ear and absolutely wanting to find out what they could possibly do in order to get a '95-'06 KDX equipped with their technology. They sent me a carb body to test fit and machine in any way possible to attempt making it fit so that I could report back to them (I sent them an extensive fitment video same as I did for Matt Denecke at Lectron), but unfortunately at the time, their SC2 36mm offering was the closest spec carb to suit our machines, and it would simply not fit no matter what on the 200 H-Series and 220R, due to frame interference at the shock crossmember and rear headstay... Keep in mind the SC2 36mm may potentially still fit a 200H engine in a '99+ KX125/KDX hybrid build, as well as possibly fitting a KDX200E frame, but the spigot dimensions are too large for the intake spigot and airbox bell diameters, and the throttle response on a 200 would not be quite as crisp when the carb is oversized, similar to how Fredette bores the PWK33/35 out to 36mm for our bikes. Great for enduro racers, bad for hard enduro and low speed technical riding etc. I'm sure the SC technology however, with their CloudForge venturi design shape, will compensate for a larger carb well, but in contrast to their SC3 34mm, the 34 will absolutely have better metering air signal due to higher velocity than any other carb at low throttle openings, and thus stands to be at the top of the market for this application.
Nathan and Corey were both a great pleasure to deal with, and were very eager to help us develop a carb offering for these still very commonly found KDX200/220 machines. The KDX's of the water cooled era 1989-2006 really were the primary woods bike option through almost that entire era, with KTM coming out with their modern lines starting in the late 1990's and becoming a bit more common in the early 2000's, with the only other woods bikes being the RMX250 and KDX250 (not terribly common) and motocross conversions.
This led the KDX to being mass produced and imported into the USA in very large numbers, hence the stunning number of them STILL out on the trails (also a testament to their reliability) 20 years after their last production year, 37+ years since the first water cooled KDX200 hit the sales floor... and they are still quite relevant with a maintenance and just a few mods and tweaks!

Thank you, Nathan, Corey, Kim, and the team at SmartCarb, for being diligent in this quest to build these newest carbs! The KDX community is much better off now WITH this option! Not to mention, it's $200 cheaper than a Lectron Billetron Pro Series!

[Chuck78]

A local KDX guy here in Ohio just got his SC3 34mm today, & immediately had to drop what he was doing to install it, ride it, & send me a bunch of pictures

I'll quote him -

"Holy $#!+, it’s amazing"

(1st message, out of nowhere... of course I immediately knew what he was talking about!)

"No dialing anything in,
Instant start up with maybe 1/2 a kick!"

Messenger_creation_3E1D55BF-20C2-4929-918F-47A359A9E12C.jpeg (219.12 KiB) Viewed 123 times

This is a guy who worked in a high end motorcycle repair/restoration shop for many years recently and is also a road racer, so I'd say those words come with a lot of validity...

I also just realized that his trick looking countershaft sprocket is a Race Tech Titanium Banshee front sprocket... I've got one of those in purple waiting here for my full titanium treatment on a postponed rebuild of my other 220, along with a lot of other fancy new parts I'm hoarding for my KX/KDX hybrid & both 220 bikes.



I wasn't in a huge hurry to get mine immediately, as all my money & time has been going into a house renovation presently, but now that I have a potential buyer before I even have the house finished, I can start putting a bit of money back into the bikes...

[SpruceItUp]

Well, I somewhat got my Smartcarb in today. It really doesn't fit my E series, not without moving the cable guide on the carb to face the right side of the bike and rerouting the cable on the bike. Even then, the throttle return is dangerous in how slow (if it even comes back) because of how the cable is pinching on the frame. Also, to even get it in I had to remove the brass adjuster from the cable completely. And the carburetor had to be tilted quite a bit to fit.
I took it for a quick rip anyways and it was running very lean, no bog, but absolutely no low end and the plug was turning very white and blistery from riding for less than 2 minutes. I started out with a dark chocolateish brown plug that my Keihin was running with, not a new plug. Hopefully this can be tuned out, as I didn't mess with the tuning whatsoever.
I also noted that the idle screw took a lot of adjustment to turn up. It started first kick with a very low idle and stayed idling there pretty well, very smoothly, but it was to low to ride properly, likely less than 1000 RPM. It seemed really rich when I first started it (lots of smoke on a smokeless oil and a very low idle) and had it on the stand, but when I started riding it was definitely lean.

I've contacted support so hopefully we can get these fitment issues sorted out. I believe if the throttle guide on the carburetor was shorter it would likely clear the frame, but not entirely sure yet.

[Chuck78]

Oh my... I'd never looked at E-Series fitment for anything but a stock-ish PWK, but it sounds like you'll need closer to a 90 degree elbow same as what I'd used to fit the Lectron Billetron Pro Series to the '95-'06 KDX. Anything less had the cable tight up against the tank. The Malossi M6 Mikuni/Keihin/DelOrto elbow was the best one as I recall, but the external metering rod adjuster may be able to be worked around with a slightly taller 90° cable guide elbow than the Malossi version if it'd permit the 90 going over top of the adjuster. The installed H-Series photos I've seen show the 45°-ish cable guide angled to aim the cable around to the side of the external metering rod adjuster.



I'll relay that to Nathan about the E-Series cable guide, but I'm sure they have sources for similar guides.
The tuning you'll definitely want to work through with Nathan/Corey @ SmartCarb.


The 200H has a much more pronounced high RPM porting configuration, albeit perhaps transfer ports that are a bit too high (typical of mid-1990's Kawasaki 2-strokes), whereas the 200E is ported to give more satisfactory torque in the lower mids and more mid-range power. Perhaps the 200E metering rod spec may be closer to the 220R settings, splitting the difference between the 200H & 220R? That's how I like to describe the power characteristics of the 3 in comparison to one another.


Keep us posted, Nathan at SmartCarb will surely get this 100% resolved for you.