Valves & riding in very dusty conditions

11 replies to this topic
  • dustbite

Posted July 21, 2008 - 02:06 AM


Hello everyone,

I am considering buying Yamahas WR 450Fs, I run a tour business in southern europe.
I have 1 major concern with the Yamahas: valve wear.
I have been reading through all valve related Qs and it seems that the Yams are very reliable in this respect.
But what about riding in a very hot & dusty (not sand) environment? The titanium valves don't come cheap I guess and I don't want to spend too much time and money on it.

My experience with KTM & Husabergs is that the intake valve wear is/can be excessive. Normally I don't bother to check the exhausts, when they become too loud I adjust them.
The good thing is: the KTM valves are cheap..

My idea on the subject: if you run your bike only in dry conditions you would be better of with paper airfilters versus oiled foam filters.

Any input is highly appreciated.


Posted July 21, 2008 - 10:36 PM


Valvetrain durability is one of the main reason's I went with the WR, but mine is too new for me to be of any help with as far as experience so far (just crossing my fingers now). You should find plenty of people here that ride in the desert and Baja that can advise. I am however a firm believer in foam filters and well oiled at that. I ride in a lot of dust and find that if I'm very careful about thoroughly oiling my filter (I like Maxima FFT because it's super tacky), I rarely find any trace of dust after a ride or two on the inside of the intake boot. The FFT is really thick and kind of nasty to work with, but I think it does it's job better than most. I have also swapped out to a Uni filter as I've done on all my bikes. Just a preference, but I think they are well made and durable. :thumbsup:

  • Imacowboy

Posted July 21, 2008 - 11:06 PM


I am too new with my WR to make any comment first hand. I have been reading all the old posts on this board (I am up to page 87) and I am convinced that I made the right call buying my bike. I am also convinced that when it comes time to put in new valves they will be stainless steel,not Ti. I have also bought two uni filters,one in the bike,and one in a plastic bag inside my gear bag.:thumbsup:

  • dustbite

Posted July 22, 2008 - 12:05 AM


Imacowboy & Outerlimits, thanks for your comments.

One very important contribution to the longevity of the Yam valve drive train might be just that: the Titanium valves.
That's why I'm not so sure that changing to steel valves is such a good idea unless you ride in wetter conditions all year around.
Anyone who has an idea about this from his own experience: please let me know.
Somewhere on TT I read that the Ti valves have a very thin and hard oxide
coating. Perhaps dust would wear this coating away in no time. That's what I'm worring about.

The other very obvious point of course is the airfilter. The foam filters are based on the principly of a very winding path for the airsteam. The particles dirt can not follow the airsteam and fly "out of the corner" and get caught in whatever sticky stuff is there.
With fine dust, made of dried up clay this is different. It is so fine it stays in the airsteam and will not get caught by filteroil.
Foam filters are used because they are cheap, easy to clean and give little resistance to the airstream.
This is my personal theory, based on my own experience. Open for comments.
That's why I think a paper airfilter would do a better job under these particular circumstances.
I am not so much worried about the fuel-air mixture. We don't race the bikes and hardly ever give full throttle.

On one of my rides someone came with a WR. After the ride there was no dust behind the filter and I was highly impressed by that fact.
The KTM setup has a poor design: the filter has a U-shape. The carburettor inlet is in the left upper corner. In that small area the filter soils up quickly and becomes dry. The rest of the filter stays relatively clean...
Husaberg filters are OK, they soil up evenly over the entire surface meaning that the air is sucked in over the entire filter and not just in one spot.
The air-filter of the Yam has aparently a much better lay out.

Did any of the readers experiment with paper filters? Anyone with a completly different meaning?

Thanks, Adrian

  • sebastiangaertner

Posted July 22, 2008 - 01:37 AM


Where could i buy these airfilters?

We went on a long trip last year Serengeti to Dar es Salaam and one KTM rider 525 (06 model) messed up his engine because of the dust. We all cleaned (changed) filters at least daily but still he got problems. So somehow i can give some experience into the theory.

I would love to get some airfilters to have them for trips like that.


  • dustbite

Posted July 22, 2008 - 02:43 AM


Hello Sebastian,

In summertime I sometimes change the airfilters at lunchtime as well.

Twinair made filters for me, just single layer, the more dense foam. They were very helpfull and came up with several solutions.
For the KTMs they also made the dustcovers from the single thick foam. But I never found a real satisfing solution.
For the Husabergs I have the best results with an inlay, it looks most like the thing woman use monthly:o Whatever passes through the main filter is caught by the inlay filter. I use Putoline oil but that's just because of easy availability..
I tried the bio stuff of several brands but with so many filters and different types of oil I couldn't get the filters clean anymore and I switched back to the good old degreaser and regular filter oil.

I think the engines could last a long time if you have a good, smooth rider and real good airfiltering.
My H'berg 550 did 20.000 km before I overhauled the top end and replaced the piston rings. The gearbox was spotless. But then again, I always ride up front ;-)
Mind you, in this part of the world you don't need full throttle that much. is also helpfull for a long engine life.

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Posted July 22, 2008 - 08:10 AM


On one of my rides someone came with a WR. After the ride there was no dust behind the filter and I was highly impressed by that fact.
The KTM setup has a poor design: the filter has a U-shape. The carburettor inlet is in the left upper corner. In that small area the filter soils up quickly and becomes dry. The rest of the filter stays relatively clean...
Husaberg filters are OK, they soil up evenly over the entire surface meaning that the air is sucked in over the entire filter and not just in one spot.
The air-filter of the Yam has aparently a much better lay out.

What I have noticed on the 07/08 WR's is that the back of the filter gets more dirty than the sides. This is probably just because it is the shortest path to the intake after the dust enters the airbox. Once the airflow is more restricted in the back, it will eventually move around to the sides.

Adrian, you might want to pose your question on the Baja board. There is nothing but dust down there to ride in and quite a lot of silt. I realize you are not racing, but you may find you get the answer you are looking for. Maybe not specifically to the WR, but to bikes in general. To be honest, I do not know of anyone that uses paper filters off road. Not to say they are not good, but just do not know anyone that uses them on off road bikes that I ride with.

One thing that would be attractive to me if I were running a tour would be to be able to clean a dirty filter easily at the end of the day. To me, the new WR's have very simple air filter access. I could see myself cleaning a filter with gas at the end of the day and bringing along a bit of oil in a small bottle to oil it back up.

Back to WR's..............I believe they have used titanium valves since they were first produced and you'll find a lot of stories here about how durable the valves are compared to most bikes now days. I don't know if it is just their process or if the smaller valve surface (due to 5 valves) is actually better for valve life. I will also swap to stainless when the time comes as I don't ride at the top of the rpm limit where the lighter Ti valves are needed.

Good luck :thumbsup:

  • dazzabb

Posted July 22, 2008 - 08:37 AM


I have ridden in some pretty bad dust in Australia and Thailand and have NEVER had a problem with the dust getting thru an oiled up foam filter and I'm sure any Aussies reading this thread would know how bad the dust is in the NT.

I don't agree with your statement about the clay dust being so fine it cannot be caught by a well oiled foam filter (dust by definition is extemely fine) because as stated above, I have never seen any dust on the small bob of grease i put after the filter in the inlet tract.

Personally I would never run a filter paper, no science or experience to back this up though, just a general feel from posts on TT etc.

Why not give Filter skins a try?

I do run filterskins, pre-oiled and installed over the filter which catch a heap of shit prior to it ever reaching the filter, then when the skin looks shitty pull it off and you have an almost clean filter below. They take up hardly any space and are easily washable.

  • Desracer

Posted July 22, 2008 - 07:37 PM


I have found that dirt is the worst enemy of the valves, it takes the coating off the valve and it goes bad fast. Heat is the next enemy, then high RPM rev limiter stuff. I have run my 03 to 330 hours and did the top end and its still running strong. My 05 has 275 hours on it and I have never had to adjust the valves. If the filter is dirty change it! I also clean the inside of the filter box with brake clean and check the intake boot with a white paper towel for dirt. The WR is a solid bike and with simple oil changes and clean filters it will last a long time.

  • dustbite

Posted July 24, 2008 - 12:21 AM


Dazzab: check out this thread, interesting reading.

No proof but I think that the dust from the soil in southern Portugal is very fine and still very destructive.
When I asked major KTM dealers in the north of Europe they never heard of severe valve recession. So I think it is related to the extreme fine dust in my part of the world.
I tried the dry filterskins, the stuff they use in the big rallys: to no avail.
Ánd I am confinced that the airbox lay out of KTMs sucks.
The KTMs have a shiny metal maze and it is always easy to spot the dust. I once checked it on a ride and was schocked, after just a 1,5 hours ride there was proof of dust behinfd the filter.
Twinair says there's no need to grease the filter contact area, the oil is sticky enough. And that's also my own experience.

Desracer, I can only agree from my own experience. I think I will start using 1 or two Yamahas and see what happens b ut from the reading in TT I have high hopes for a good result.

thanks for all the input,
dustbite Adrian

  • yz-dwg

Posted July 24, 2008 - 09:25 AM


I live and ride in Arizona, can be very dusty especially when riding with my quad buddies, I ride at least once a week and I am not very diligent on my air filter cleaning, i just checked the valves after I hit 2500 miles and they have exactly the same clearence as the first time I checked them at 500 miles, I dont get dust behind the filter though and run either the stock one for play and a no-toil for race. my .02c

  • ckroto

Posted July 24, 2008 - 05:12 PM


plus one on the filter skins. They are great. worth every penny:ride:


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