Posts
830
Joined
2/8/2012
Location
Mira Loma, CA, USA
Edited Date/Time
4/29/2022 1:13am
Decided to try racing Hard and Hounds this year(they’re really fun btw). Miles and miles of chocking dust. Noticed after the first one that I had some very very fine dust inside my air boot. I’m borderline neurotic about my bikes and don’t cut any corners when it comes to making my bike last, so this situation was worrisome. I used a UNI filter at the first one and thought maybe that was the issue. So I bought a new Twin Air, resealed my air boot to make sure, and I have always used Maxima FFS. I raced the second one a few weeks ago. Finally got to pulling my bike down yesterday and the issue is still there. Pulled the airbox apart and everything looks like it’s sealed up. The dust is equally distributed around the whole boot, so it would seem it passing through the filter as opposed to a specific leak somewhere. Is it possible the filter is just passing the fine dust? Is there a better filter out there? Maybe FFS is not what it used to be? Any hard core desert racers have any input? Only time I’ve aver has this issue was my one attempt at No Toil, but immediately went back to was always been perfect for me- UNI/Twin Air and FFS. Any input?
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Fully coat your filter with a pour-on filter oil, then work it through generously and squeeze out the excess. Do not twist or wring the filter out, though. I wear rubber gloves for this procedure. You should have a uniformly green air filter (blue FFT or Bel-Ray oil + yellow filter = green.) Your filter looks like it has "hot spots" of oil all over it, with dry between.
Is that the correct filter cage? I'm not sure if KTM or Kawasaki runs billet cages. In any case, do those locating holes in the filter attach somewhere?
I do not grease the rim of my fliter; as long as the whole filter is treated with the filter oil, the pressure from the filter cage will seal off the rim.
Here's a tip for putting on the air filter oil: poke two holes in the seal of the bottle instead of tearing it out. You can then "drizzle" oil onto your filter in a much more metered way.
One thing I am going to address is the cage. I checked the fit on it and it bottoms out on the center post before contacting the sealing lip. Probably a 6mm gap between the cage and the sealing surface. This may be enough pressure to seal the filter, but I’m going to “tune” it a bit to make sure it clamps down better. With the filter installed, I can slide the filter out from underneath the cage by pulling on it, so it could for sure us a little more clamping force.
One thing I wasn’t clear about was the level of dust. I’m not talking a dusty race- I’m talking 2 straight hours of fog levels of dust. I’ve only ever had this issue at these 2 events- Hare and Hounds. Keep in my mind I haven’t figured out this bomb run thing yet, so I I’ve been starting back of the pack and eating dust the whole time. Point being- I think what I’m asking my filter to do is beyond 99% of normal conditions people ride their bikes in.
I also got a chance to talk to a very very experienced and successful desert racer. This guy knows how to prep a bike and has the titles to prove it. I told him my issue and he said. “DON’T use FFS. I had the exact same problem 20 years ago”. His solution was “use Twin Air original oil.” Per him it’s the best stuff.
So it looks like you guys nailed it on the head. I’m going to implement those two changes and give to a try. I’ll post an update here with my results. Thanks again gents!
any update?
My KTM 350 sucked some dust last summer when I raced a fast offroad race in dusty conditions. I use Valvoline airfilter oil wich is very tacky like glue allmost but that didnt help. Will try twin air oil and see what its like.
I'd say that 6mm gap chuckie108 has noted Is the culprit. That he can pull the filter sealing lips out, reinforces it.
Not good, not good at all.
I really hope he's not incurred a lot of expensive wear to his engine.
That ultra fine dust he mentions - well, plenty of us here in Oz know about it - talcum powder particle sized, but in no way 'soft'. I've been at events where we'd change filters at Every check point.
I normally use FFS with the stock KTM/twin air filter and cage. FFS is like water when you put it on. Last year at the Ironman GNCC bikes were getting dusted out. My 125 started running pretty rich by the end of the race but the boot stayed clean. If you have a good filter setup the bike will choke up and die before it gets dust through the filter. If you can pull the filter past the cage rim without ripping it, it isn't tight enough. How does the outside of the filter look after 2 hours of dust race? I have heard the extra dust filter twin air sells will help too.
I saw a Youtube video from Ariemann where he mixes motor or two stroke oil 1/2 and 1/2 with air filter oil and swears the motor oil keeps the air filter oil from drying out and allows it to trap more dirt before choking out the engine. He claims the motor oil will keep the filter surface wet and keep grabbing dust into a thick layer on the outside of the filter.
I have not seen dried out FFS or twin air filter oil from filters that get washed more often than every 3 months.
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