How I Installed a Lectron Carb On My '99 KDX200

[Chuck78]

I have a whole thread on this forum about the Billetron Pro Series fitment.

[Kevbot]

Hey @Chuck78, I ordered the H Lectron but it hasn't shipped yet I could maybe reach out and change my order. I do have the 220 w/V3 Reed, I mostly ride slower/chunky terrain but some single track.
Would you still recommend the Newer version with the larger diameter?

Just found your thread on the Billetron, is Lectron sending the carb with the corner machined?

[Chuck78]

Yes I would absolutely recommend spending more money on the billetron pro series. If you can justify the cost. I didn't realize they were still spec'ing the H-series / HV-series Lectron for our bikes, I thought the only thing they offered for our bikes currently was the 34 mm Legacy era Power Jet carb.

The Billetron Pro Series 38 is still actually a 34mm bore at the slide area of the venturi, FYI, has to keep the air velocity high or better atomization. The Billetron Pro Series Big Air version is probably closer to an actual 38mm bore.

There's definitely a significant upcharge for the billetron versus the other Lectron models. I do really like my legacy era powerjet Lectron on my 220, but the Billetron Pro Series offers even more. And you can use OEM throttle cables instead of a custom Barnett or Lectron throttle cable.

Also, your VForce3 reed cage intake is not a good fit with the older Lectrons. I've run that setup 3 years now, it contacts the frame pretty heavily on the top cover, and the corner of the fuel bowl where the hose guides are actually sits in between coils on the shock spring... Not good. A Boyesen RAD Valve fits the Lectron Legacy Power Jet carbs slightly better, but stock intake assembly fits those the best.

Opposite of the Billetron Pro Series, the 34m. legacy series Lectron Power Jet carb fits a 95-06 KDX best with the VForce3 or Boyesen RAD Valve. A 95-06 with stock intake + Billetron Pro Series definitely requires an angled mounting position on the carb clocking and/or swapping an engine mount bolt for a low profile button head or conical socket head design bolt.

[Kevbot]

Not sure if it is the H but whatever one they have listed for the KDX on their website. I reached out to them and asked if I was able to upgrade since my order hasn't shipped yet. Thanks for the insight Chuck!

[Chuck78]

Good luck! The legacy era power jet carbs are the ones they spec for 95-06 KDX's.
Not the H-series. H-series are slightly better but not as good of fitment from what I gather.
The Billetron is an improvement over the H-series, and the Billetron Pro Series is an improvement over the original Billetron...

Just FYI the first person to originally reply to me at the general customer support email for Lectron told me the Billetrons do not fit a KDX at all.

I knew better than that from their published dimensions, and happened to talk to Matt Denecke outside of his main day job at Lectron, and he sent me an original Billetron carb body from their scrap bin, with top cover and fuel bowl, to test fit, and I proved that even unmodified, they are a good enough fit, and far better fitment than the older Legacy era Lectron Power Jet 34mm carb they do call a direct fit for our bikes.

Another guy at Lectron keeps contacting me trying to get me to buy a Billetron Mini intended for 85cc / 100cc/106cc/112cc super mini MX racers, as this guy runs one on a KTM 250 & says it runs absolutely awesome, with the best low end response ever... But 28mm or 29mm will limit the top end, although the porting on a stock 220 will also limit the top end,so perhaps on a 220, this wouldn't be so bad? But the carb would be the opposite physical installation fitment, it'd need interference-fit (heat up) aluminum bushings to increase the size to the PWK33/35 inlet and spigot sizes...
The Billetron Pro Series 38 being actually a 34mm bore where it counts will work awesome on a 220 or 200.
The Smart Carb SC2 36 might give even better low end response, but I don't know if they'll fit well at all. That remains to be seen.
Lectron was VERY EAGER to help me out, and responded at least weekly if not in 1-3 days. Smart Carb would take a month to respond as they're very busy for the staffing they currently have. I never got any action out of Smart Carb's eagerness to help, but they said they literally get a KDX customer request every 1-2 days, year round, and they would love to know what fitment issues their newest generation of carbs have with our KDX's, as they could sell a lot to KDX owners if they fit better.
The Billetron Pro Series is the best fitment of any upgrade aside from a genuine PWK35 Air Striker of course, but I'd rather have a metering rod carb any day...
The SmartCarb will give the absolute best throttle response and fuel efficiency, but since there are no additional circuits beyond the metering rod, if the fueling curve of the metering rod is not perfect to achieve good adjustment at all throttle positions, then a metering rod swap needs to take place, and this can get costly and time consuming.they cost significantly more than sone Keihin jets or jet needles... But once dialed, you'll truly have the ultimate.
The Billetron Pro Series is clearly the better fitment out of all metering rod carbs, and has the 2 supplemental adjustable jet circuits to more easily dial in the fueling curve without a metering rod swap 96%+ of the time, so this is the clear winner for our bikes at present.

[Kevbot]

Got a quote for the 38mm Pro and you were not wrong on the price tag!

I could get the non pro billetron for $100 less, but then you loss the torque jet.

[Chuck78]

I don't know how I feel about the non-pro Billetron price vs a standard Lectron Legacy 34mm powerjet carb. I'm not sure if the performance would be much different than the older 34mm, but the fit would absolutely be better.
If you have two to five days to wait, when I put my Billetron Pro Series onto my '97 220, I can test fit my standard Lectron 34mm on my '99 220 that still has the stock reed cage and intake, and give you my opinion of the fit then. I've been running the standard Lectron 34mm Legacy Power Jet carb with a v-force 3 reed cage assembly which pushes it back A LOT further and makes the fit not good at all, but it does "work." Would not recommend it though, it makes pretty hard to contact with the frame and like I said the lower hose guide on the float bowl bolts sticks out into the coil spring area of the shock and I had to position the coils just right so that there is no interference. Boyesen RAD Valve would be slightly better with the old Lectrons, but stock intake/reed cage is definitely going to be best on the older Lectrons on a 95-06 KDX.
I know people even with the stock reed cage and intake have cut and modified their frames to make the dimpled area recessed up higher, in order to better fit the standard Lectron 34mm... Somewhere here is a video of a guy cutting out the weld and putting a bottle jack into his frame to push the dimpled area up higher....

The Billetron Pro Series I'm very excited about. There's a chance I might have it on for a Saturday ride if I can make it out, and if I can get it tuned decent enough just riding around the alleys in my neighborhood.

Matt from Lectron actually reached out to me yesterday to ask if I was needing any assistance getting it tuned properly. I've heard he follows up with nearly every customer like this to make sure they are happy.

[Kevbot]

Going for the Pro, hopefully its here after I get the top end completed and can get out and ride.

[Kevbot]

If anyone is interested they do a little machining on the billetron for the KDX.

[Chuck78]

Not sure I mentioned it on this post before, but I discovered that you need a 90° or 45° elbow cable guide for the top of the carb most likely. They shipped mine out with no cable adjuster or cable guide (they sell what they call a slip cable adapter @ $13-15 which is just a threaded adjuster for cables like the KDX/KX that don't already have one), but it appears we will need one of the short radius metal elbows with threads on the carb side and an adjuster on the top side to receive the cable housing termination fitting. This might necessitate a KX125/KX250 cable from a PWK36/PWK38 carb application if the stock KDX cable doesn't have enough cable length to add the adjuster, & absolutely will require the longer KX125/250/500 2-stroke cables if you want a quick turn aftermarket or KX throttle (recommended!).

Mikuni Keihin 90° M6 x .75 cable adjuster guides

Screenshot_20230824-220610.png (2.12 MiB) Viewed 2382 times

I have 2 different 90° cable guides that just arrived tonight. The 45° & 40° versions are a lot more common in the USA though, & they may work better due to being more likely to fit the stock cable length. The Sudco 45° cable adjuster guide elbow may be best, but I also see a lot more of the 40° versions. I'd think 40° would be cutting it close to the tank, but perhaps not.

I'll report back soon.

I'll also be reporting back to Matt @ Lectron to make sure he knows of this.


EDIT - to run Kawasaki KX/KDX cables, it appears that an adapter of this sort is necessary for proper cable fitment:



EDIT of my edit - those adapters are a 6mm diameter end (0.236" o.d.), but the Lectron slide seems to need a very slightly smaller end around .228" or .230" according to my machinist's drill bit set as inside bore gauges...

The specific Lectron cables by Barnett are intended for the older Lectrons, and the Billetron advertise that they use the stock OEM cables in most applications. From what I'm gathering I believe you're supposed to use your stock slender Keihin PWK 's vertical cable end in the larger horizontal cylindrical hole as the slide is a universal fit for both styles of cable?
I also had found YZ owners questioning this same thing.
Here's a YZ125 owner's picture from ThumperTalk:

Billetron slide YZ125 owner

20220302_181454.jpg.7c8a5af3152c48162a876c1071a7ff10.jpg (169.57 KiB) Viewed 2284 times

On a KDX, shortest length 40° or 45° or up to 90° cable adjuster elbow is definitely almost mandatory as the tank sits so close to the carbs. That's how other members had designed cables for the older electron carbs in the earlier posts on this topic, custom cable with a 70° or 90° elbow.

Also the 45° Mikuni/Keihin cable adjuster from Niche Supply on eBay was not made well at all, and the Keihin PWK cable end doesn't quite slide through them due to burrs from the manufacturing process (tubing seam on the inside). Bummer. The 90° short elbow will be it...

If I can get my tire change, wheel bearings, and other work done today before 2PM, I might actually get to putting this on today. If not, maybe tomorrow night. Honda buddy coming over this afternoon with all sorts of mechanical problems on two different XR's, needing help...

[Chuck78]

https://www.ebay.com/itm/394000427103

I just ordered an actual Sudco-supplied 40° cable adjuster/guide elbow from Parts Giant on eBay, a reputable business, so that I'm less likely to get cheap Chinese forgeries/clones of the good parts. Sudco part # 007-730. The Niche Supply elbow from eBay which looks almost identical but not quite, ended up being poor quality and not actually fitting a Keihin carb's cable end through the elbow due to casting burrs or more correctly, internal tubing seam irregularities (common on economy-made metal tubing).
If I can clear the underside of the fuel tank on this Sudco elbow, I'll call that the best one for the job, as a 40° bend is going to give less friction than a 45, 70, or 90° bend, and less wear on the metal elbow vs stainless cable. I'll be sure to grease the inside up quite well with molybdenum chassis grease (the black chassis grease for automotive steering and suspension parts as well as the best lube for all suspension linkage and swingarm bearings for our bikes, moly is far better for these applications and for splines than standard bearing greases).




I believe this should do it, using either a KDX stock cable for stock KDX throttle, or a 1990's KX125-500 throttle cable if using a KX throttle or aftermarket quick turn throttle. My KDX throttle is broken where the cable screws in, and the 220 that I ride full time has a Motion Pro quick turn throttle, but I'll try and compare to make sure the length will work out with an OEM KDX cable and KDX throttle grip. Worst case you abandon your original used cable and throttle and upgrade to a used $25 KX125/250/500 2-stroke throttle (or new aftermarket for $35-$40) and matching new cable for $9-$25.
I found it odd that the Lectron slide had the larger horizontal cable barrel end configuration, but that it didn't match the 6mm (0.236") slip-on brass adapters I have as the hole in the slide was a bit undersized at 0.228" or 0.230". I will probably shave .003" off the brass adapters I have and use them (.006 total diameter reduction via emory cloth hand sanding) just because I'm pretty particular about details, but the cable fits and functions totally fine without that using the stock Keihin cable ends. I found it quite odd that it didn't have a receptacle for the standard Keihin type cables, and I looked up the 2005-2008 KX125/250 2-stroke cables from the Mikuni carb years, and they appeared to have the same carb slide end fitting as the Keihins as well... odd.