2016 KX450f Air Fork

[Jroush418]

Hey guys I have a 2016 Kawasaki KX450f I'm putting a Timbersled on. I just have some questions about my air fork options. I am a mechanic at a bike shop in Colorado and am familiar with the forks. I know the air fork isn't my best option but I am going to run it this year. What kind of pressures are people running. I know the stiffer the better but I have never maxed out my air chambers. Any input would be greatly appreciated.
Thanks in advance!
Jake

 

[peakperf]

I am running a YZ450FX, my buddy has a 2017 KTM450 with the air forks. 1.5 hours on the bike he hits a cross ditch and compresses the front forks. It then locked at 1/2 of normal travel leaving the ski about 8" lower than the track. Apparently this was a big issue in europe with the aer48 air shocks when they first came out. When the seals are cold and a sudden compression occurs the seal is stiff and fails allowing pressure from the upper and lower chambers to mix. This creates a vacuum inside the shock preventing it from fully extending. The only time the chambers can equalize is at full extension. Bike is still on warranty and this is a known issue so we decided against putting a bottle jack from the ski to the tripletree but that is probably the only way to extend the air fork once the vacuum has been created unless there is a release valve on the bottom of the fork. Either way, your ride that day is done. There will be old school springs inside his forks for the next ride.

 

[Norma Stitz]

I have 50mm marzocchi supermoto forks on my snowbike and they have about 1.5" less travel than a typical dirt type fork but they are valved and sprung very stiff for street racing and they are working fantastic on the snow. I hit some big bumps, and fell into some deep holes last ride and they felt great. They also have full valving and springs in each leg, in other words they don't separate tasks which always bugged me on some modern forks. Anyway, just wondering if anyone else has run supermoto forks on snow and what their thoughts are. I was thinking I'd need to add oil and maybe use thicker oil but now I'm not sure that I even need to do any mods at all.