I have been wondering about the air intake on K100. Reason for this? Mine does not have that air intake tube that leads fresh cold air to the airbox. Previous owner said it was too ugly to use (and he did not save any parts he abandoned..). Well I drove the bike last autumn (some 760km) and it worked well - but this is the first K I've been driving and weather was pretty cold.

There is a motorcycle scrap yard near and they have one K100 there, so I might be able to get that part and instal it to my bike. Then again, if it is not doing much anything, I'd rather not. I manufactured my own little spoiler to the airbox, but I don't really think it makes any difference.

Other point of view. How about driving in rain? How much water ends up in airbox without that tube? So.. Quest for the tube or just leave it like it is? Whis is: http://kotisivu.dnainternet.net/ajk73/Cafe_3.JPG

I guess that the meaning of this tube when the fairing is removed is not big. Since there is no warnings in this topic yet.

Sorry tenox, I can't answer your specific question, but I asked a similar one before. Even with this tube, I felt that there was scope for water to get in if it was really wet. The consensus view I got was that it had not been a poroblem al these years.
Without the tube, I'd be worried about foreign matter getting in, and also the temperature of air intaken down at that level wouldn't be as cool. That should get some technicoheads
excited. At least I'd be putting a wire frame in front of the intake hole. (we have rats here who love warm engines.)

i noticed when i saw a k1 that there was a drip hole before the induction tube entered the air- filter box at the lowest point ...

the air tube, taken from infront of the radiator returns the air temperature of the atmosphere (current temperature ) as it enters the airbox ..i have measured this .

i imagine that in really cool climates that there is some warming involved as the airbox retains some heating affect as it is behind the radiator on a faringed bike and before it enters the plennum which could be an advantage at lows speeds and exteemly cool weather ..

but for us poor sods out here it is all hot hot hot ...in anything above 30 degrees c ...(most of our summer and spring riding )

it is interesting to note that if i head inland (away from the coastal humidity and a a higher elevation 5 degree c difference ) the bike seems to run smoother ...and much more comfortable to ride

i think "caferacer 62" noticed some difference in performance when he opened up the air path into the filter box on a standard k bike

charlie99 wrote:i noticed when i saw a k1 that there was a drip hole before the induction tube entered the air- filter box at the lowest point ...

The K1 intake tube is lower as it has to pass the side exit ducts from the radiator shroud:



Without the drain it would soon fill up in our wetter climates.

If yours is a naked K bike, K100 or K75, I would use the intake snorkle for a K1100. I would not run the bike without an intake snorkle.

Themason wrote:I would not run the bike without an intake snorkle.

Why not?

I would run the intake tube from a K100 in preference to a K1100 any day. The K1100 has the same size opening as one throttle but a K100 is much bigger. I don't see where your logic is comming from.

Tenox, have a look at Caferacer62's setup.

Looks like you could paint it red or chrome and it would be a perfect match for your bike.

rossco

This guy asks "Why Not" when he asks the forum for
advice about his air intake and he receives such advice?
BMW engineering is
very meticulous when they build a machine and all of the intake air piping is
designed in such a manner for so many reasons. Some might be performance, other
reasons might be intake noise resonance considerations or perhaps it's partially
considerate of the final emissions calculations.
My point here is:
#1 If
one asks for advice from more experienced others, he might consider accepting
such advice without asking why.
#2 I believe the best policy is and always
will be: "Stay Stock". Any time you make an alteration from the "as delivered"
configuration of a precision machine, no matter what "improvements" one might
perceive from such alterations, there is always some offsetting detrimental
reductions in overall performance weather they are apparent to the "fixer/rider"
or not.
If removing the fairings to change to a "naked" configuration, one
should obtain at the very least, all of the correct parts for a bike that was
delivered naked from the manufacturer.

I have to say that I agree totally with ibjman on this subject - these bikes were built a long time ago (some of them at least) and the fact that any of them are still giving reliable service is a tribute to BMW's original attention to detail, design and engineering skill. Whilst I appreciate that folks like to "personalize" their bikes, I am a firm believer in the old adage "If it isn't broken, why fix it !" Just my opinion and don't wish to cause any offence here. I love to look at "custom machines" but these wonderful old bikes came off the production line in pretty good fettle and I like to keep my machines as close to "factory" as possible.

Rant over - sorry folks

"Opinions are like arseholes - everybody has one"

Aah Krambo, i've got a problem, I've got plenty of opinionns, what should I do????? What does it mean????? Keith
P,S. Opening up that inlet must by all rights change the paramaters that the air works under no matter how small the change. It's a change?

if there is no need to change.... i agree

but we all dont live at the same latitudes with similar weather patterns and for some of us ...we do like to make the wheel better ,,,for our particular application

some do understand the changes and consequences that we explore in search of a better experience

personally i dont "go there" untill i have a backward path, be it a fairing or a wheel, a bolt or nut ...

life is far too enjoyable to be all wearing the same design vest or shoes

sometimes we have to adopt an inteligent substitution ....for not all of us live in the little circle of millions of folks with similar ideas ...just around the corner

imagination and need for change should not be scoffed at ...

we have an shared appreciation of some great design ideas by the manufacturer and rejoice in that fact ...

viva la "k" in all its forms is all i can say

Tenox if you are worried about some crud getting in there, then service the aiirbox and see how much crud has got in there. Maybe all that will happen is the filter will be 10pc dirtier maybe not, if the snorkle is gone then there will be less resistence to air flow as it no longer has to negotiate the snorkle. whether the snorkle delivered any ram effect isnt known to me, blokes have said it made no noticable difference to them when missing. Perhaps its easiest to replace it for peace of mind

rossco wrote:Tenox, have a look at Caferacer62's setup.

Looks like you could paint it red or chrome and it would be a perfect match for your bike.

rossco

Sure looks good. I just don't have any motivation for modifications anymore before spring. Maybe next winter then. Now the choises are: 1.) Keep the existing spoiler 2.) Try to get and install original one.

I think the original could be painted too? Red or the same colour as the rear end of the bike (which is the colour most of the now copperish parts will be painted next winter anyway). Anthrazite (or something like that) is the colour.

ibjman wrote:
#1 If
one asks for advice from more experienced others, he might consider accepting
such advice without asking why.

I disagree. I have no way knowing who (irl) is giving me instructions and on what basis. If advice is given, it should be with state reasons. Then I can myself decide if reasons are - in my case - good enough to go with the advice given. I dont think that anyone should go ahead and do stuff according to someone unknown advices if there is no explanation why to do it. In the internet someone can give you advices that are completetly incorrect - jus for fun (I'm not saying that this is the case now).

#2 I believe the best policy is and always
will be: "Stay Stock".

My policy is quite the opposite. If I would want a stock machine for riding, it might not be K100 anyway.

If removing the fairings to change to a "naked" configuration, one
should obtain at the very least, all of the correct parts for a bike that was
delivered naked from the manufacturer.

I agree this on that level, that if I would have done the change myself, I would have left that snorkel there or atleast left it in my storage. Unfortunately I bought the bike as it was, and without any parts that were removed from it.

Mate, the original ones should be readily available. Probably not advertised a lot as folks think they are not worth a lot to sell.
If I had a spare one here I would send it to you. 2 bits of plastic and a rubber sealing ring.
I will look in the garage and see what I can find.

Have a look at anyone nearby selling parts and ask if they have one. Surprising how many people list the big price items and ignore the rest.

Will let you know.

rossco

edit.
In all honesty and given the conditions you ride in and the naked condition of your bike i think you would be perfectly justified to not install the snorkel and just leave the bike as it is.
I cannot imagine the amount of cool fresh air you would have around the intake. Makes me shiver thinking about it.

K75cster wrote:Tenox if you are worried about some crud getting in there, then service the aiirbox and see how much crud has got in there. Maybe all that will happen is the filter will be 10pc dirtier maybe not, if the snorkle is gone then there will be less resistence to air flow as it no longer has to negotiate the snorkle. whether the snorkle delivered any ram effect isnt known to me, blokes have said it made no noticable difference to them when missing. Perhaps its easiest to replace it for peace of mind

Thank you. This helps me a lot. If there is no significance change in performance I can easily just monitor the airbox (how dirty it gets or doesn't get) and then decide if I need the snorkel or not. Bike has been driven (according to the previous owner) about 6000km after changes and before I bought it. That is an estimate since previous owner did not have any speedo or odometer in it. Checked the airbox this winter and it is (as is the air filter) very clean. Then again bike has not been ridden in rain etc. at all. What comes to the performance I will get somekind of an answer this summer when I get to take this K100 to an airfield for top speed test. (Standing mile.)

rossco wrote:In all honesty and given the conditions you ride in and the naked condition of your bike i think you would be perfectly justified to not install the snorkel and just leave the bike as it is.
I cannot imagine the amount of cool fresh air you would have around the intake. Makes me shiver thinking about it.

Yep.. Weather prediction for today. 20cm more snow. Just started snowing. I sincerly HATE spring in Finland. It seems first that the summer is just around the corner and then the spring throws tons of new snow in your face.

I think I will ask what that snorkel costs at the scrap yard nearby. If the price is reasonable I might buy it just to be sure. I do like the bike more without it though.

Move. Autumn here. Today was 29. Tomorrow about 27.

The ocean is still about 21c and will be warm enough for a swim for another 6 weeks.

just saying

What comes to driving a motorcycle I find that the best temperature is around +18 - +22 celsius. I have driven in conditions ranging -2 to over +30. When it gets to +25 or so you get too hot if wearing decent driving gear. I really don't like driving without good gear. I have given up a bit and bought kevlar jeans for the hottest days, but still have leather jacket, leather gloves and biking boots even when it gets to +30.

I actually have 3 different gears for different weathers. Only real problem on cold days are the hands - if not heated grips available. Lets be honest though. From 0 to +8 celcius riding is not that fun - but the urge to drive at spring outwins the cold.. I will get my K out of the garage as soon as the driveway to larger road is clear of snow and ice and temperature is on plus side.

Edit: Unfortunatetly the weather forecast was right. About 15cm of snow allready at ground and more coming. There is an old saying in Finland (well this is a part of it) that goes: "Maalis maata näyttää, tiet tukkii ja ojat täyttää" translation is something like: March is the month that shows the bare ground, messes the roads and fills the trenches. Well.. We have had about 50cm new snow this march.. No ground visible anywhere! This is 3rd winter in a row with loads of snow. Before these there were few winters with almost no snow at all..

Also, emailed the scrap yard owner. Snorkel costs 15 euros so I will get it thursday or friday. Not sure if I install it, but it will be there if I choose to do so.

[quote="Rick G"]I would run the intake tube from a K100 in preference to a K1100 any day. The K1100 has the same size opening as one throttle but a K100 is much bigger. I don't see where your logic is comming from.[/quote]



The K1100 intake tube is much larger. It fits into the same lower airbox as a K100 but does so without the rubber gasket so the area if the hole the air is flowing through is larger. It definitely flows more air than the K100 part and has a better shape. WIth K100RS and RT models, however, you will have to cut away some of the right fairing vent to fit one. On an unfaired bike it is a simple bolt on.

Moving air exerts less pressure than standing air. In aircraft, a round hole in the fuselage of a moving aircraft pulls air out of the interior of the aircraft, not the other way, unless you have some sort of scoop or NACA duct. A hole in a flat surface can flow air in either direction with equal facility. Moving air is at a lower pressure and will draw air out of the airbox, or an aircraft. That opening will also create a buffet known as Helmholz effect that does nothing good for fluid flow (air is a fluid). A great example of Helmholz effect is the sound made when you blow across the top of a soft drink bottle. In submarines, openings in the hull can create strong enough Helmholz effect to make them audible to sonar, and in some cases can even create resonant vibrations that do structural damage.

That snorkel also brings in air that is cooler than the air at the side of the airbox, benefitting power and fuel economy.

Themason wrote:Moving air exerts less pressure ...
That snorkel also brings in air that is cooler than the air at the side of the airbox, benefitting power and fuel economy.

Hi there, I think that The Mason nailed it, without the snorkel you'll be denying air to the engine, except when stopped.
If you put a conical or cilidrical filter perpendicular to the airflow the sucction effect behind the filter will overcome the pressure the front causing the same lack of air to the engine.
A scoop like device or snorkel at the front of the vehicle is required to capture de air and induce it to the air chamber.
Best regards.
JAP

Another example of Helmholz effect I neglected to mention is also known as "bomb bay resonance". In WWII bombers, when the bomb bay doors were opened in flight, Helmholz resonance would create a really uncomfortable pressure pulse inside the whole bomber, causing ear and sinus discomfort for the whole crew. You can get a similar effect when you open the sunroof of your car and drive at speeds that set up the resonance in the car's interior (at least my Audi is prone to this and it is darn uncomfortable).

Now imagine the effect on that vane in your air flow meter to a resonance in the airbox like that. Talk about screwing up the fueling of the bike!

Bought the damn snorkel. Not sure if ever install it, but I have it now! (Some whisky etc. in blood maybe..) So here this for music for my ears: https://www.youtube.com/watch?v=hFPlGDKgiYc

have a look at this snorkel....or should I say Ram Cold air intake

Themason wrote:

Rick G wrote:I would run the intake tube from a K100 in preference to a K1100 any day. The K1100 has the same size opening as one throttle but a K100 is much bigger. I don't see where your logic is comming from.

The K1100 intake tube is much larger. It fits into the same lower airbox as a K100 but does so without the rubber gasket so the area if the hole the air is flowing through is larger. It definitely flows more air than the K100 part and has a better shape. WIth K100RS and RT models, however, you will have to cut away some of the right fairing vent to fit one. On an unfaired bike it is a simple bolt on.

May I suggest you remove you foot from your mouth buster and compare the top end of the tube it IS VERY MUCH SMALLER than a K100. I could suggest many other things but I wont for the sake of harmony on this forum.

Tenox...hear you about having to have the snorkle.

Hope that works for you.

Thanks - never heard that band before. Dont like the vocals but the song is OK.

I've seen completetly redesigned airboxes on these K:s. Wondering do they need modifications to ecu too (and to exhaust). Is there a Power Commander for K100 existing?

I'm just bored of all this snow and coldness... Would like to ride but can't. :|

what you need is a K100 snowmobile with a heater then you will be set

Tenox wrote:Thanks - never heard that band before. Dont like the vocals but the song is OK.

I've seen completetly redesigned airboxes on these K:s. Wondering do they need modifications to ecu too (and to exhaust). Is there a Power Commander for K100 existing?

I'm just bored of all this snow and coldness... Would like to ride but can't. :|

I thinl most of the redesigned stuff around is not so much a performance improvement but someone playing around and experimenting as for a power commander I was told some time ago that one was available but I could not find any reference to it on any site that sold them retail but that could mean that they are not available new.

Personally, I have a hard time believing that knowing they were making
10 more hp w/the 4V, that BMW engineers would take a step backward with
an air snorkle design that flows less air.

Shape of the whole assembly also has a lot to do w/flow. Hard/tight right angle bends especially so. :|

Do you suppose that the engineers changed the shape of the intake snorkel, not to admit more or less air so much as to increase it velocity???????
It seems to me that a certain displacement piston cyl. combination is going to inhale a specific volume of air on the intake stroke.
would a smaller snorkel increase the air speed while allowing ( relatively) the same or similar amount of air?
I think perhaps we need to consider the bigger picture here, but I am an untrained amateur not an engineer like some of the more brainy types here.

I will be removing the fairing from the K1100 in the next few days and will give measurements etc. but flow rates are a possibility sa the snorkle is a very different shape but I would say from experience that even acounting for shape the flow rate would have to be impeded because of size.
I recall working out the areas of the cross sections about 2 years ago but didnt keep the figures so will have to do it again.

Decided to go on with my own spoiler for now. I will paint the snorkel with other plastic parts of the bike next winter and possibly install it then (thinking of doing the bike little less shiny then anyway). Unless there is some problems (water, dirt or performance issues), then I'll try the snorkel sooner. Thank you all for helping at the issue.

ibjman wrote:Do you suppose that the engineers changed the shape of the intake snorkel, not to admit more or less air so much as to increase it velocity???????

Air velocity is a function of speed of the machine. Most likely the snorkel is designed to optimize air flow at the limits of the machine and speeds below that would be sub-optimal, but acceptable IMHO. (yeah, I'm an engineer too.)

Reading what themason had to say about bombay doors and considering what our roads are like if finland have as rough a set of roads as we do then I think I would be putting the snorkle on to at least offset the damage the roads are doing, we need that map flap to be happy dont we.

If you mean sand or dust or gravel etc. only problem we have is the gravel used to sand the road at winter. It is an issue only shortly at spring. I dont drive (with K anyway) on other surfaces than tarmac. I may be putting some off road tyres to K year 2014 (if I get second pair of rims or another bike). Then with the gravel and stuff the snorkel will be installed too.

Our road have dips hills and corrogates that shake your filling also a (w) effect as the trucks leave their mark on the road surface, its amazing to think that we spend millions on roadways and then some bozo tradie comes along with little or no understanding of road make up and will dig across it and then reinstate it to his satisfaction not the roadways or mine for that matter (once sat a 6week course on road reinstatement years ago) bet the tradies have not done that..Our main roads are OK but the back roads where its more fun to be are hard on the but and the bike for that matter, gravel sand water wash aways are all part of the experience over here

http://goo.gl/maps/JxZwu

There is an example of smaller roads nearby where I live. Seems to be taken springtime few years ago. Road condition is not great (holes and bumps etc.) but there are no sand or water or things like that normally on the roads. Of course there are smaller roads and gravel roads but the kind on my example are the ones I prefer when riding my K.

Yes thats just like the ones I like, not much traffic good scenery room to stop for the pictures.

[quote="Rick G"][quote="Themason"][quote="Rick G"]I would run the intake tube from a K100 in preference to a K1100 any day. The K1100 has the same size opening as one throttle but a K100 is much bigger. I don't see where your logic is comming from.[/quote]



The K1100 intake tube is much larger. It fits into the same lower airbox as a K100 but does so without the rubber gasket so the area if the hole the air is flowing through is larger. It definitely flows more air than the K100 part and has a better shape. WIth K100RS and RT models, however, you will have to cut away some of the right fairing vent to fit one. On an unfaired bike it is a simple bolt on.[/quote]

May I suggest you remove you foot from your mouth buster and compare the top end of the tube it IS VERY MUCH SMALLER than a K100. I could suggest many other things but I wont for the sake of harmony on this forum.[/quote]



Sorry but very much I know what I am talking about. The K1100 intake is a standard performance upgrade used with modified L-Jet air volume determinators (air flow meters) and it makes a noticeable improvement in throttle response. There is a lot more than the size of the entry hole going on with that snorkel. Look at the shape and learn some fluid dynamics.

Btw, the gentleman I learned that from built and tested the prototypes of the K100 and K75 when he worked for BMW Research. It is what he uses on his modified bikes. If you think you are smarter than he is about K bikes, well .............

[quote="Tenox"]Thanks - never heard that band before. Dont like the vocals but the song is OK.

I've seen completetly redesigned airboxes on these K:s. Wondering do they need modifications to ecu too (and to exhaust). Is there a Power Commander for K100 existing?

I'm just bored of all this snow and coldness... Would like to ride but can't. :| [/quote]



Can't adapt a Power Commander to L-Jetronic, and really L-Jet is tunable enough you don't need an outboard device like a P-C. That big ram air duct will cause more problems than it solves however. Ram air causes the vane in L-Jet to do strange things. You can reduce horsepower with too much ram air.

[quote="ibjman"]Do you suppose that the engineers changed the shape of the intake snorkel, not to admit more or less air so much as to increase it velocity???????
It seems to me that a certain displacement piston cyl. combination is going to inhale a specific volume of air on the intake stroke.
would a smaller snorkel increase the air speed while allowing ( relatively) the same or similar amount of air?
I think perhaps we need to consider the bigger picture here, but I am an untrained amateur not an engineer like some of the more brainy types here.[/quote]



Look at the shape of the K1100 intake snorkel. It starts out small but gains size as it approaches the airbox, and actually has a larger diameter than the original as it enters the airbox because there is no rubber boot. What BMW is doing is slowing the air down as it enters the air box. Slow air is dense air. The shape of that new snorkel is very well thought out, and is a big part of the reason that K1100RS have such a bulging side panel on the fairing. To fit one of those to an early RS like mine requires some serious cutting into the vent area.