new Lectron Billetron Pro Series fitment on KDX200 / KDX220
Posted: 03:34 pm Jun 24 2023
I've been running a Lectron 34mm power jet carb for 2.5 seasons (previous owner installed just before he decided to sell it due to 1st baby on the way), & I've been LOVING the improved atomization and fuel range / economy / mileage that these carbs deliver, as well as the excellent low end response. My 2nd KDX220 with this Lectron 34mm runs AWESOME, but I'm always looking to modify these KDX's even more, to make them even more viable against modern Euro 2-stroke woods bike.
The newest Lectron offering, the Billetron Pro, is leaps and bounds more advanced than any other carb option we have, hands down. The SmartCarb SC2 36mm works amazingly on KDX engines transplanted into KX125 etc. hybrid builds so I've been told, but SmartCarb and the chinese rider-owned company XTNG that make very similar carbs, both look likely to be a very tight and questionable fitment on a '95-'06 KDX frame due to the external metering rod adjustment on top and other external dimensions, and already being tight since they're closer to the length of a standard long body carb (78mm Billetron, 82.5mm SmartCarb SC2, 87mm XTNG Gen3, 91mm PWK35).
https://www.lectronfuelsystems.com/billetron_38_pro_series
https://www.lectronfuelsystems.com/billetron-proseries-38.html
Matt Denecke of Lectron Fuel Systems is an AWESOME guy, first off. Lectron previously had no fitment info for our bikes and said the Billetron Pro doesn't fit the KDX frame. Several KDX owners had speculated that the Billetron's modern short body form factor (+ mandatory Billetron long body adapter added to the airbox side bell) actually looked like it would fit our KDX's better than the older long body standard Lectron offerings.
Chatting with their new Lead Fuel Systems Engineer Matt Denecke, who also owns Apex Engineering and makes billet cylinder heads and other trick parts to keep Yamaha YZ 2-strokes alive and viable against modern European machines, he was eager to assist me in figuring out what issues we'd have fitting the KDX with the newest and by far the greatest incarnation of any Lectron metering rod carb.
Matt was the perfect guy to talk to, as he's very enthusiastic and dedicated to keeping older Japanese bikes like the YZ250 still viable machines, and same with his eagerness to help me figure out if we can work out fitment for the Billetron Pro Series onto the H-series KDX's and possibly the E-series as well (I have a buddy with an '89 I might try to test this on also).
I asked Matt if they had any way to 3D print a Billetron Pro body, or had any scrap/prototype bodies they could turn the inlet spigot down on a lathe to the PWK35 long body size. Next thing I know, an empty blem/scrap Billetron 1st gen body shows up in the mail!
I knew the carb body was very wide, and their engineering department advised that it will interfere with the KDX frame. Well, they modify the 34mm Lectron for our KDX's due to frame interference, let's see what we're dealing with here!
With the 46mm Billetron intake spigot turned down to the PWK35/33's 42mm o.d., I found that this fit my retired mostly stock '99 KDX220 rebuild project, although it doesn't quite rotate up to level left-right as the body was up against the lower rear head stay engine mount bolt and the body was angled from being level a bit, but still plenty good enough to call a fit. A little bit of material could be filed off the corner of the carb to be able to get it a bit closer to level.
The GREAT NEWS is that on my '97 220, I found exactly what I suspected from my first test on the '99 220's stock intake - that the VForce3 reed cage and intake and the Boyeson RAD Valve reed cage/intake (that both make the 34mm standard Lectron a very poor fit that is NOT recommended), actually make these short body Billetron carbs fit BETTER than with the stock intake/reed cage!
Since the airbox to carb to engine path is angled from the outboard airbox connection & inward to the center intake on the engine, the further back you push the carb, the further away it gets from the head stay engine mount brackets and frame tabs! This is a huge win for us here...
The 45 degree angled corners on the top cover touch the frame's welded on headstay mounting tabs with the VForce3 or Boyesen RAD Valve, but with either of those, the carb is able to rotate a lot closer to level horizontally left & right than with the stock intake/reed cage, but still not quite vertical.
one more clearance shot. I'll pull the top cover to see how much gasket surface we have to work with, and we very well may be able to shave this thing down with no harm to anything, after all, Lectron takes a LARGE amount of material off the side of the 34mm carb to clear the KDX better. I highlighted in my videos to them how they only really need to shave the top side and top cover edge within 8mm of the side corner though.
My Lectron 34mm is installed with the ill-advised VForce3 intake, and fits poorly and sits at a very noticeable angle, but it still RIPS, and works pretty awesome. This Billetron Pro fitment doesn't quite sit level as-is, but the angle is almost level within a few degrees and is very acceptable to me, and far closer to level than I've been running the Lectron 34mm.
I'll probably take the carb body to a metal working belt sander and shave some material off in the next few days to see how much better I can get this scrap test fitting body to work out, but even as-is, just running the VForce3 or Boyesen RAD Valve + Billetron long body adapter in the airbox bell, this will fit pretty darn good and give is the closest thing to fuel injection type performance that we'll get for our KDX's!
...to be continued
The newest Lectron offering, the Billetron Pro, is leaps and bounds more advanced than any other carb option we have, hands down. The SmartCarb SC2 36mm works amazingly on KDX engines transplanted into KX125 etc. hybrid builds so I've been told, but SmartCarb and the chinese rider-owned company XTNG that make very similar carbs, both look likely to be a very tight and questionable fitment on a '95-'06 KDX frame due to the external metering rod adjustment on top and other external dimensions, and already being tight since they're closer to the length of a standard long body carb (78mm Billetron, 82.5mm SmartCarb SC2, 87mm XTNG Gen3, 91mm PWK35).
https://www.lectronfuelsystems.com/billetron_38_pro_series
https://www.lectronfuelsystems.com/billetron-proseries-38.html
Matt Denecke of Lectron Fuel Systems is an AWESOME guy, first off. Lectron previously had no fitment info for our bikes and said the Billetron Pro doesn't fit the KDX frame. Several KDX owners had speculated that the Billetron's modern short body form factor (+ mandatory Billetron long body adapter added to the airbox side bell) actually looked like it would fit our KDX's better than the older long body standard Lectron offerings.
Chatting with their new Lead Fuel Systems Engineer Matt Denecke, who also owns Apex Engineering and makes billet cylinder heads and other trick parts to keep Yamaha YZ 2-strokes alive and viable against modern European machines, he was eager to assist me in figuring out what issues we'd have fitting the KDX with the newest and by far the greatest incarnation of any Lectron metering rod carb.
Matt was the perfect guy to talk to, as he's very enthusiastic and dedicated to keeping older Japanese bikes like the YZ250 still viable machines, and same with his eagerness to help me figure out if we can work out fitment for the Billetron Pro Series onto the H-series KDX's and possibly the E-series as well (I have a buddy with an '89 I might try to test this on also).
I asked Matt if they had any way to 3D print a Billetron Pro body, or had any scrap/prototype bodies they could turn the inlet spigot down on a lathe to the PWK35 long body size. Next thing I know, an empty blem/scrap Billetron 1st gen body shows up in the mail!
I knew the carb body was very wide, and their engineering department advised that it will interfere with the KDX frame. Well, they modify the 34mm Lectron for our KDX's due to frame interference, let's see what we're dealing with here!
With the 46mm Billetron intake spigot turned down to the PWK35/33's 42mm o.d., I found that this fit my retired mostly stock '99 KDX220 rebuild project, although it doesn't quite rotate up to level left-right as the body was up against the lower rear head stay engine mount bolt and the body was angled from being level a bit, but still plenty good enough to call a fit. A little bit of material could be filed off the corner of the carb to be able to get it a bit closer to level.
The GREAT NEWS is that on my '97 220, I found exactly what I suspected from my first test on the '99 220's stock intake - that the VForce3 reed cage and intake and the Boyeson RAD Valve reed cage/intake (that both make the 34mm standard Lectron a very poor fit that is NOT recommended), actually make these short body Billetron carbs fit BETTER than with the stock intake/reed cage!
Since the airbox to carb to engine path is angled from the outboard airbox connection & inward to the center intake on the engine, the further back you push the carb, the further away it gets from the head stay engine mount brackets and frame tabs! This is a huge win for us here...
The 45 degree angled corners on the top cover touch the frame's welded on headstay mounting tabs with the VForce3 or Boyesen RAD Valve, but with either of those, the carb is able to rotate a lot closer to level horizontally left & right than with the stock intake/reed cage, but still not quite vertical.
one more clearance shot. I'll pull the top cover to see how much gasket surface we have to work with, and we very well may be able to shave this thing down with no harm to anything, after all, Lectron takes a LARGE amount of material off the side of the 34mm carb to clear the KDX better. I highlighted in my videos to them how they only really need to shave the top side and top cover edge within 8mm of the side corner though.
My Lectron 34mm is installed with the ill-advised VForce3 intake, and fits poorly and sits at a very noticeable angle, but it still RIPS, and works pretty awesome. This Billetron Pro fitment doesn't quite sit level as-is, but the angle is almost level within a few degrees and is very acceptable to me, and far closer to level than I've been running the Lectron 34mm.
I'll probably take the carb body to a metal working belt sander and shave some material off in the next few days to see how much better I can get this scrap test fitting body to work out, but even as-is, just running the VForce3 or Boyesen RAD Valve + Billetron long body adapter in the airbox bell, this will fit pretty darn good and give is the closest thing to fuel injection type performance that we'll get for our KDX's!
...to be continued