Upgrade to enjoy this feature!
Vital MX fantasy is free to play, but Premium users receive great benefits. Premium benefits include:
- View and download rider stats
- Pick trends
- Create a private league
- And more!
Only $10 for all 2026 SX, MX, and SMX series.
Engine back in and starting to re-assemble wiring and such:
I'm a fan of black radiators, so I drilled out the bracket rivets, took them all off, and had the radiators anodized black. Then re-riveted the brackets back on and we're good to go. It's a pain in the ass to do all that, but it's a lot better than cerakote:
Motostuff lightweight rotors provide the stopping power front and back. I’m a bigger guy (200 lbs.), so I really like the extra stopping power of the 280mm front rotor, plus these are quite lightweight relative to other options out there.
And you can’t go wrong with Renthal for the sprocket. We’re running a 14/51 sprocket ratio on this build, same as stock. I’ve found that gearing to work well on our old 350 for most tracks in the area.
Pirelli MX32 tires provide the traction. These are fairly lightweight tires and work well for most tracks in the area. I like the larger front tires for a little more traction and comfort, so the front is the bigger 90/100-21 size. Rear is the standard 110/90-19.
Overall this makes for a great package for the bike and for me. But it comes at a cost of increased weight. The stock wheelset is really lightweight, but not very durable. These wheels will be super durable, have the larger front tire, and oversized rotor. Because of that, they’re 965 g (2.125 lbs.) heavier than the stock wheels. That’s annoying, but I feel it’s a reasonable trade-off for the increased strength and performance.
I could cut some more weight out of this with exotic tubes, superlight rim locks, etc., but for now we’re just going with standard tubes and motion pro rim locks as they’re super reliable.
Here are some weight numbers for those interested:
Complete Wheels (tires, rotors, everything pictured):
Front Wheel: 8,450 g
Stock Front Wheel: 7,980 g
Rear Wheel: 11,395 g
Stock Rear Wheel: 10,900 g
Faster USA Wheels (hub, spokes, nipples, rims only):
Front: 3,500 g
Rear: 4,460 g
Pirelli MX32 Mid-Soft 90/100-21: 3,890 g
Pirelli MX32 Mid-Soft 110/90-19: 5,215 g
Kenda 80/100-21 Standard Tube: 462 g
Sedona 2.75/3.00-21 Standard Tube: 520 g
Kenda 110/90-19 Standard Tube: 702 g
Sedona 100-110/90-19 Standard Tube: 623 g
(I ran the Kenda front, Sedona rear)
The Shop
Luxon 4-Post Bar Mounts
$189.95 - $239.95
Free shipping: VITALMX
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
PS- everything looks awesome so far.
If you really want a long lasting sprocket, the Dirt Tricks steel sprockets are nice, but they're a lot heavier than an aluminum sprocket.
The swingarm came out a little more grey than I had hoped, which is a typical problem for anodizing castings. The KTM swingarm we did came out darker and more black. The key difference was that we put the KTM swingarm into the stripping tank prior to anodize and we did not for this one. I guess that’s what we’ll do in the future. Regardless, this still looks pretty good!
You may be familiar with our KTM/Husky/GasGas linkage knuckle we’ve developed with N2D suspension. It softens up the rear end and has a much more progressive curve than stock. Combined with a spring change and valving, it makes for a great package that really helps settle the rear end, increasing traction in chop, and bottoming resistance. It all works great as a package. But, we’re working with MX-Tech suspension with this build (and some other things in the future), and part of that package is changing by using their National shock. In this case, the knuckle needs to change, and rather dramatically.
We now have a knuckle that does the exact opposite of the N2D knuckle and is the most linear motion ratio available (to my knowledge, at least). The national shock has a unique bottoming control system, the Huck Valve, so with bottoming controlled by damping, we can make the linkage curve far less progressive. And with valving to suit, this works out to be a great setup as well. Notice I keep saying that everything is a system. You can’t just take a knuckle and slap it on expecting great results, you need to change the rest of the system to match! Usually that means valving and springs, but sometimes it takes even more than that (huck valve, etc.).
The difference between the N2D and MX-Tech knuckles is obvious when they’re side by side:
With the adjustable linkage arm and larger knuckle, you might think that we’re adding weight to the bike. But we’re actually losing a good amount instead! The adjustable length arm, plus MX-Tech knuckle, plus the races and bearings all add up to 939 g. That’s about 170 g lighter than stock (0.375 lbs.). We’re using our ultralight linkage arm race in that (hardened steel DLC coated races on an aluminum carrier) in that, but even without that it’s still 113 g lighter than stock.
The bearing race uses a machined aluminum carrier to position and hold the actual bearing races. This starts as some US made aluminum in our lathe:
This is after the first operation. Most of the carrier is machined, it’s then flipped around and the other side is finish machined to tolerance and concentricity.
The bearing races are hardened steel from a reputable bearing company. We then have those DLC coated for reduced friction and increased hardness. These have just been DLC coated. It’s an industrial high-performance DLC, so it comes out a little more grey than black, but it’s a tougher and longer lasting blend specifically for this application:
The races are press-fit over the freshly anodized carrier. We went with the popular “Kashima” bronze color on the anodize and finished it up with laser etched logo and part number. Here’s a bunch of them. They end up 0.125 lb. lighter than stock and have lower friction due to the DLC coating on the races:
Either way Luxon stuff is top-shelf. No one can argue that.
The brake tip needs to match the foot pegs, right? Pro-Pegs just happens to make one of those! It’s titanium, just like the foot pegs and available through Motostuff.
Exhaust systems are REALLY hard to come by right now and have been for a while. Luckily for us, langhammx was selling a new Akrapovic setup here on Vital, so I grabbed it. Full titanium system and it’s really lightweight. The exhaust system is a really good place to save weight on the KTM/Husky/GasGas bikes, plus it’s got that bling factor that’s super important…
Breaking or losing the brake pedal return spring has been an issue on the KTM/Husky/GasGas bikes for a while now. Some people replace it with a Honda spring, which is supposed to work well, but I really like the Fasst-Co setup. It moves the spring inline with the master cylinder and keeps things out of the way.
I’ve decided to run a sealed (o-ring) chain on this build to try one out as I’ve never used one. I know there’s a lot of talk about how they rob you of power, but I haven’t seen any actual evidence of this, so why not give it a shot? It feels hard to bend right out of the box, which would seem to require more power to turn, so the claims initially makes sense. But I’d like to feel it after it’s been broken in. There’s a big difference between feeling two new chains (one standard and one o-ring) and making a comparison between both of those chains under power, mid-moto, dirty, and when the lube has worn off of the non-o-ring chain. I think that may be where the o-ring chain shines as it is “permanently” lubed.
This is the RK 520MXU chain, which is the lightest sealed chain I could find. I know there’s been rumblings of RK chain issues, but I’ve never broken a chain and this one looks well built. There are all sorts of variables in how a chain can break – badly riveted together (I just use the master link), incorrect chain tension (I measure it so it’s correct and not overtight), and a really fast pro abusing it (I’m not that fast), so I’m betting it will be just fine.
Pit Row
We recently came out with oil filter covers for the Austrian bikes and they fit most of the four strokes. There’s no performance advantage, they just look nice. They also have an extended outer lip, so it’s easy to grab with your fingers to remove and change a filter. I’ve had to grab some pliers to get the stock one off in the past, so this is just a little easier:
The 350 has had issues for some time with the cam chain tensioner not building up tension right as the bike starts. We’ve used the Dirt Tricks tensioner in the past and we’re using another one for this build. I didn’t take a photo as there’s not much to see once it’s installed! These are a nice upgrade as it fixes the noise issue, you toss it in and forget it’s there.
We closed off the axle entirely so it’s a fully sealed system. This is annoying as you can’t use a triangle stand, but really nice as it keeps the mud, water, etc. out of the middle of the axle, so it’s a trade-off, but I think it’s worth it. They look really nice when paired with a titanium adjuster bolt and nut, which is also a Motostuff product.
These blocks are similar to the stock KTM stuff as they’re “fixed” and not “floating” like the Japanese brands are. I use quotes around those as the blocks are fixed with either setup once they’re torqued down. There is no such thing as a floating axle block, and no one can tell the difference between the two on the track, despite what some test riders may say. I’m in the middle of a blog post now that will go into details on that, and will post a link once it’s online.
And of course dropping weight is always a performance increase. That's the main benefit of this part.
From the front of the block to the back end of the locknut:
From the back of the block to the end of the swingarm (using the depth measuring portion of the caliper):
Post a reply to: Luxon MX Motocross Action Mag FC350 Build (Complete)