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The shock is essentially a full pound lighter than the stock shock, which is great too:
Those weights aren’t exactly apples to apples as the stock spring was a 42 and the spring on the National shock is a 48. The MX Tech shock also comes with titanium mounting bolts, which is a nice touch.
Now that I have a shock on the bike, I'll be able to put the rear end together. More posts coming soon!
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
They come with a fork cap tool, a nice Bondhus Allen wrench for adjustment, titanium axle clamp bolts and even titanium fork guard bolts. All of which are nice touches!
Weight-wise, these are pretty light and come in at 7835 g vs 7255 g for the stock AER forks. 580 g (1.25 lbs) isn’t too much of a hit for spring forks instead of air.
These clamps will come standard with our Gen2 split triple clamps. The fork tubes are the same size as the Japanese brands, which is just a bit different than the Austrian brands, so they won’t slide right into regular KTM clamps. Here are some detail shots:
Looking forward to a report regarding the suspension.
A
D
We were out of stock on the triple clamps, so I had to steal the clamps from this bike and send them to Stank Dog so he could run the Blackjack forks on his 125 in time for SX. But we've wrapped up another batch of those since and they're back on the bike now.
An updated shock is on the way from MX Tech too, so I'll post details of that when it arrives. Plus there's a lot more, just haven't had time to put it on. But we're getting there!
Question about that swingarm:
Are you concerned about the hard anodize affecting fatigue strength at all? I know hard ano does terrible things to the fatigue strength of 7075 (and the thicker the layer, the worse the effect) but I’m not familiar with how it acts on cast parts.
In general, all anodize will reduce fatigue life of all aluminum. The anodize layer is a lot harder than the aluminum substrate below it, so the anodize layer cracks relatively easy and that causes the aluminum below it to crack and eventually fail.
It's not really a big deal for regular type II anodize (what you see on most aftermarket parts) so long as the anodizer sealed the anodize correctly. It will still reduce fatigue life a little, but not by much. And it's worth noting that the increase in corrosion protection form anodize can increase fatigue life relative to a corroded un-anodized aluminum part.
It's a bit of a different story for Type III (hard) anodize as the anodize layer is a lot thicker than type II. But in the case of a swingarm, it's primarily designed around stiffness goals. Once those design goals are met, the part is far stronger than it needs to be. So, I'm not too worried about the loss of fatigue life with the hard anodize on a part like a swingarm. I wouldn't do it to a set of triple clamps, though!
I like to run a skid plate on my bikes, but don't want something overly heavy or stiff. Just something that adds some protection. The Husqvarna skid plate fits the bill. It's rather pricey, but it's a perfect fit and not overly large. This attaches using three bolts that thread into the existing holes in the frame. The front two bolts are rubber isolated so it doesn't affect frame stiffness as much as a solid mounting would. It is a little over a pound, which isn't ideal, but everything else about it is really nice.
And finally, I found a photo I took earlier, but didn't post yet. We're using these SKF bearings on our KTM/Husky/GasGas triple clamps. They're identical to OEM in size, quality, load capacity, etc., but they're using a polymer bearing cage and a couple less rollers, so they're a touch lighter (12 g each bearing).
Fun fact: SKF is a swedish firm. SKF stands for Svenska Kullagerfabriken (Swedish Ball Bearing Factory). They hit the nail on the head with their name!
Our engineering business (Luxon Engineering) recently quoted some injection molded parts for a customer. A particular part was quoted in PEEK, Ultem, and Polypropylene, but otherwise identical. Piece pricing on the part was $0.73 in Polypropylene, $5.36 in Ultem, and $21.74 in PEEK. That's quite a cost difference!
Pit Row
Most people already know about the 2-stroke filter cage trick to remove the backfire screen, but here they are side to side. The two stroke cage on the left (without the screen) and the four-stroke cage on the right (with the screen):
The filter support has some surprisingly sharp corners. They probably wouldn't be a problem, but it only takes a minute to smooth them out a little:
Here's what the stock seat assembly weighs:
And our new seat assembly:
So we shaved some weight (~0.2 lbs) with the Guts seat foam and cover. This is their velcro system cover, which makes installation and adjustment easy. We've had this sitting in the box for quite some time, so once this has a chance to "form" around the seat and unfold itself, I'll pull it tight again to smooth out the wrinkles:
For the plastics, we went with Cycra. These bolt right up without issue and everything aligns really well. Their "stadium plate" is very popular in racing and it does a great job of protecting the triple clamps from roost. But it also hides them, which isn't so good for a company trying to market triple clamps! So we're running an older Acerbis front plate that does a better job of showing them off for the camera.
Most of the bike is back together now, so it's starting to look complete. There's still a lot of details to add, but we're getting there!
https://nihiloconcepts.com/collections/ktm-350-sxf/products/ktm-husqvar…
Hoping to slowly form my WE in to this category of builds over time!
Threads like this are another reason I'm 100% drawn toward the brand over other options! Finally submitted "the" email and I'm hoping to add luxon to my ride sooner than later!
The stock Brembo brake carrier is pretty heavy, and being at the end of the swingarm, that’s important unsprung weight that can be lost. So we wanted to apply the same tech that we use on our triple clamps to that part and remove as much weight as possible without sacrificing strength of stiffness (maintain a firm braking feel without vibration/squealing). First up is to measure the stock bracket so we know the hard points of what we’re making. I used the probing system on our CNC machine for that:
Then I created a CAD model based on that with “material that needs to be there” – all the hard points like axle bore, caliper pin mounting, pad surface support, etc., and “material that can be there” – basically just a big volume of material that can exist without getting in the way of something else. This CAD model is then put in to our analysis system where I performed a topology optimization (aka “generative design”). The optimization simulates the braking loads and removes excess material from the “material that can be there”, leaving the most optimal material for performance. Here’s a video of the optimization iterations:
From this we come up with a 3d CAD model that represents this optimization result, but can actually be machined. This is then analyzed and iterated on a few times until we’re happy with the result from a stiffness, weight, and stress perceptive. Here’s an animation of the analysis of the braking loads:
Once the design is well sorted, we have to program the CNC machine to actually cut it out. Here’ a video of the program simulation on the computer before being done on the machine. It’s super handy to simulate the CNC program first to avoid any expensive mistakes!
Then it’s on the machine. The raw stock is held on a serrated vice and the first setup is machined (before and after photos):
Then we have to machine a set of vice jaws to hold on to the odd shape of the bracket so we can hold on to it and machine the other side (setup 2, vice, before machining and after):
Then the final setup needs yet another vice jaw machined (forgot a photo of that), and the last little bit is machined away (before and after):
The finished bracket is then tumbled in porcelain media to remove sharp edges and give it a little shine, then a quick test fit to make sure all bolts together:
Then it’s off to the platers for electropolish and anodize. When we get it back I laser etch logos and part numbers with our fiber laser:
Here’s the final product:
The end result is nearly ¼ pound (100 g) of unsprung weight removed without sacrificing stiffness or strength. Plus it looks pretty cool…
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