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To keep the heat off the tank?
Shock
That's a good eye there ML. Help me understand though - how would channeling hot air from the radiator fan to the shock help prevent shock fade? Isn't shock fade caused by heat?
So we're feeding preheated air from the radiator to the shock?
Ooookay...
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Thats the anti-front tucking device. Seriously, I know people.
Would depend on what the temperature of the air directly around the shock was, wouldn't it? Preheated air can still be significantly cooler than other air.
I thought the KYB forks were the most interesting part on Sexton’s KTM?!
*Is he still using them??
The radiator is the hot part. The air going through it is room temperature and does not get to the temperature of the radiator by passing through it momentary.
Or to run it hot all of the time and keep it in the hotter window?
Yes.
Understood, but it's definitely warmer than ambient air. Seems like if you're trying to cool the shock it would make more sense to be feeding it ambient air through a duct rather than warmer air.
Maybe there's enough velocity/flow to keep the temp where they want it, though. And this is assuming that our assumption is correct. 😁
Feeding it how? Via a forced air system already on the bike?
^You guys are all correct about the airflow from the radiator, in other words, yes, it is hotter than the ambient air, and yes it is also not as hot as the radiators. The part you are missing is how much cooler it is than the shock, which could still benefit greatly from some airflow, even if that airflow is relatively warm. if it's still cooler than the shock is, it will help cool it down.
EDIT: Since it is driven by a fan, it helps even more. A continuous stream of slightly warmer air will cool the shock better than an occasional breeze of cool air.
sounds logical
I once took a Ducati 1299 Panigale for a quick test ride. It had an Ohlins shock with remote reservoir, which was placed where it would occasionally touch my leg. I was shocked (ha) at how hot that lil bastard got after a short ride over some bumpy city streets, so I can imagine Sexton’s suspension reaching nuclear temps on an SX track. A blowtorch might be a little cooler.
Read Pit Bits…
Not already on the bike - that duct wasn't on the bike, it was added. I was thinking they could have turned that fan 90 deg to the outside so it draws from the cooler air and feed that duct. Now, if they're trying to kill 2 birds with one stone in having forced convection on the right rad to cool it and they're also trying to cool the shock with forced flow using that warmed air exhausting from the rad, as long as they're getting the temps they want out of both then that's what matters.
But I can't see the other end - maybe it's a seat warmer? 😄
I had a buddy running the Florida Winter series in '82 on a CR250. To train for it we'd run a sand track that was nothing but whoops. That shock would get so hot in a short amount of time that you could spray water on it and it would steam.
Pit Row
Not missing that part, just questioning why you'd go for warmer air since you'd get more cooling with a greater temp differential by using ambient air, but like I said in the other post, if you're hitting both temp targets that's all that matters.
And we're all still assuming that's what we're looking at.
The fan on the radiator has greater benefits outside of feeding this duct. I'm not following your logic.
Not sure what the disconnect is so I'll tell you what I'm assuming to help clarify - that they are using the ductwork to feed forced air to the shock to cool it.
If that's the sole intent, then it would provide greater cooling effect if they used a cooler source of air. However, if they have a dual-purpose for it (cooling the radiator and the shock), as long as the temps of both rad and shock are in their intended target range then that's what matters (mission accomplished).
What greater benefits outside of these are you referring to?
The fan forces more air through the radiator especially in slow, tight conditions. Adding the duct is just reaping more benefit from a part already present on the bike.
i bet it’s like this weird box on eli’s kx we never identified 🤣😂😏
There was an oil cooler behind that, the ducting was to feed the oil cooler. We posted about it a ton when it was on the bike.
i know michael, i was hoping the three emoji things would help show the sarcasm i was trying to lay down… i will do better next time i promise!
edit: someone doesn’t have a sense of humor
KTM is utilizing Rotella”s latest synthetic shock oil, needs to be warm at all times for proper performance.
I heard it counter balances the weight of the front end tucking.
I kid
Sorry, I thought that was pretty much understood. As someone who grew up riding tight single-track we know that's the reason for a rad fan - to move air through it when you're not moving fast enough to get sufficient convection.
I was trying (and apparently failing 😄) to make the distinction between having a fan solely for the shock-cooling benefit and installing it in such a way to provide a cooler intake source versus the installing the fan in the customary location behind the rad just because that's more convenient. However, if they're already using the fan to cool the rad and if the routed exhaust from it can also provide sufficient cooling for the shock, then yes, addition of the ductwork to the fan's present location makes perfect sense. I hadn't seen the rad fan on the SX bikes previously, but I admittedly haven't paid that close attention to that area.
Hope I'm a bit clearer now and thanks for elaborating. 👍
'Carb Heat'
Must be getting icing at the altitudes he's jumping to
Could it possibly be something for sound testing? Duct hot air into the air box, lower the volumetric efficiency and raise the thermal efficiency a bit. Maybe also trigger some mapping changes in the ECU when it sees hot air via the inlet temp sensor? Just spitballing...
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