Airbox delete on a 4v k100, understanding

[Reinier]

Initial state of the bike with 255K on the clock.


Current state:


This winter also planning to fix the fuel gage and do some painting. If there is enough time

[sooprvylyn]

That looks nice.
I was actually looking at a set of angled K&N filters.

I will try the catch can with a filter on top to ventilated.
This will reduce a lot of tubing making a cleaner instal.

Ventilating a bit is ok, my main goal is getting rid of the airbox and the only mess on top off the engine. Which probably means that some of those tubes are leaking. And replacing those special BMW tubes can get expensive.

This will probably be my winter project. At the moment enjoying driving after changing all controls dash and creating a totally new wiring harness.

Airbox delete is pretty easy. Just pull everything out, plug the small hole under the radiator, put some caps on the small holes on the back of the throttle bodies, attach a catch can to the breather at the back top side of the engine, fit pods....the last thing you need is a place to put the o2 temp sensor. I have a file for a bracket that will attach to the back of your throttle bodies that puts the sensor right between the cones. Lmk if you want it.

[Reinier]

My cat h can came in today
It looks and feels good and came with a mount and a set of different size hose fittings.

But it dit raised a question.
I noticed that the normal filter exit in top is directly connected to the input connector, before the baffels.

This confused me.
I expected it to be an alternative output.

When I blok the out and connect the filter there will be no airflow through the can so it will be similar to putting the filter directly to breater hose.
And as sooprvylyn found out that is not good for your filter

I want the catch can to do his work and catch most of the oil in the fumes. And then ventilated the "cleaned" air through the filter.

Does that make sense ? I can easily mount the filter on the out port.

If not where do I go with the output port? To the throttle bodies I assume. And would that be better with or without the filter.
As the crankcase is OEM connected to the throttle bodies with only the seperator in between and no valves I assume this would be an option.

[Laitch]

Are the throttle body plates at the tips of the red arrows the "baffels" to which you refer?

[Reinier]

No no no.
The baffels are the perforated plates in the catch can that are supposed to made the oil in the vapor condensatie.



The in-port of the catch can and the "normal" filter port both connect to the same space just above those baffels

[sooprvylyn]

I got the same "problem" on mine.  These cheap oil cans have this design flaw  there are 3 solutions:

1. plug the top hole and put the cone filter on the can output hole...this is the better solution of the 2 and probably what I will do with mine.

2. Plug the input hole, leave the filter on the top as designed, and use the output hole as your input. This is less ideal as the pressure will be pushing up on the filter from the reservoir side, but I think it should still work.

Possible 3rd solution: stuff the wire packing material that came with it into the top of the oil can before you attach the filter on top...instead of in the small packing material receptical between the "screen holes".  then plug the output hole and use the input hole and cone as designed.  Will probably make it hard to repack at a later date.

[Reinier]

I agree and will use the first solution. As in the picture I posted.
Makes the most sense.

[sooprvylyn]

Do you have a plan for mounting location?  I am a little struggling to find a good spot to locate my catch can where it will look clean.

[Reinier]

Nothing final yet as I have not remover the airbox yet so I can not do any try fitting.
But my can came with a mounting bracket that can be bolted to a horizontal surface.
And the airbox is mounted to the top of the engine.
When it is removed they should be some free bolt holes.
I want to reuse one of them. And put the can somewhere in the middle, probably in the lower part of the engine so there is enough room to use the dipstick..
As my engine will be dull black the red can behind the filter pods wil give a nice contrast.
And at the right front behind the radiator I am planning the coolant over flow can made of a Monster Energy can.

[sooprvylyn]

I did an airbox delete on mine. The battery now sits above the block in a bracket that uses those old airbox holes. No more room for the catch can there. Mine also has that bracket.

I mounted my coolant overflow on the right behind the radiator like you plan to do. I used the screw holes in the radiator for the bracket.

[Reinier]

I have a lithium batterij in my seat and also a m-unit.
And the motronic sits between the frame tubes under the tan/seat.
So I have lots of room left over.

[sooprvylyn]

I have a lithium batterij in my seat and also a m-unit.
And the motronic sits between the frame tubes under the tan/seat.
So I have lots of room left over.

lucky....i had to keep a passenger option for the missus, so no under seat battery for me.

[sooprvylyn]

I have a lithium batterij in my seat and also a m-unit.
And the motronic sits between the frame tubes under the tan/seat.
So I have lots of room left over.

I found a pretty elegant solution for the catch can. There are 2 potential mounting points, the steel brace in the frame is where I'm mounting, but there is also a threaded ground hole next to the shift lever on the gearbox that is perfectly placed.  If I were to mount to the gearbox hole, I'd probably drill it and tap it larger tho. The steel brace is already quite strong, and could be easily modified to fit this bracket on the bottom instead of the top where I have it.

This unit comes with the bracket and fits perfectly. Just need to add a cone filter and swap the input hose barb to a 1/4 npt x 5/8" barb fitting(or a G1/4 to 14-16mm hose barb if you can find it).

Comes in red too
Catch Can New HEMI Technology Z-Bracket fit for Scat Pack & Shaker 11-21 (Red) https://a.co/d/eZsKzBq

[Reinier]

Looking good.
I can not do that as all that space between the frame is already used.
An I am trying to get the see through of the triangle in the frame as clean as possible.
By the way I can still carry a passenger if needed, but not planning to. I restored the misses bike last winter so she can not complain.

I hope the paint job on mine will be just as good

[sooprvylyn]

Yeah, my rear triangle is empty, except for this new oil catch tank...which sits pretty high right under the seat dead centered on the rear wheel, and is actually a substantially smaller unit than the unit you got.  Will probably look pretty good there too, once I swap to the red can. There is another small can that will fit above and behind the radiator nicely, but doesn't come in red. Lmk if you want to see that unit

 Anyway, just wanted to alert you to an option that seems to be well purposed and well fit to our specific bike.

[Reinier]

A small update. I removed the airbox and discovered a 5mm hole in the breather hose. That explains the mess.
I removed the throttle bodies and gave it all a good clean and installed the new filters. I also removed the 4-way hose and capped the tubes on the throttle bodies.




I found some oil residu on the butterfly values what makes sense when the breather fumes are returned there.The new setup should keep them cleaner.

Now I need some pliers to refasten the clips. Then some more cleaning and some inspection of the header rubber before they go back on the bike.

I did do a preliminary test of the filters in combination with the catch can and all was fine. Maybe even a bit better then before.

[sooprvylyn]

I used these boots on mine. They are pretty thick, but they fit ok once tightened down.

https://a.co/d/gQfyWnG

If your intake boots are cracked as they often are, you can look for some 40mm boots like these instead of ordering the oem ones. I bet you can find the same thing in black too. These are super beefy and durable. I have zero worry about them ever cracking.

[Kaos]

Soopr, i think he ment the intake manifolds, as he has connected the breather directly to the TB. Some here refer to them as boots.

[Reinier]

I meant that Is still need to do a proper inspection of the intake manifold. The boots Soopr mentioned I cleaned and reused they had some wear on the edge of the metal clips but it was superficial. So I reused them for now.
The breather is no longer connected to the TB. But to the catch can. Oil fumes are caught there and not fed back into the TB

[sooprvylyn]

Soopr, i think he ment the intake manifolds, as he has connected the breather directly to the TB. Some here refer to them as boots.

Yeah, I used them instead of the stock boots to connect the throttle bodies to the intake manifold.

[Mill]

I know I am late here, but wondering the significance of the 4-way hose on the throttle bodies on the back breather tubes on the carbs, isn't this needed for syncing airflow across the carbs,

I saw they were blocked off and wondering is that okay long term or main purpose, they are $160 for OEM from euromoto and don't know if that was needed or not.

Looking at following this for air box delete.

The second thing was the front breather hose near the radiator, does this need be blocked off or routed with the catch can on this.

[Reinier]

The 4-way hose is only for environmental issues. It transport an air oil mixture that comes from the carter due to over pressure. You could vent it directly to the outside. But that is not being kind to the environment. BMW's solution is to route it back into the air intake so it will burn in the next cycle. Another part is in the airbox. This splits most of the oil from the air. The hose to the front of the engine returns the split off oil to the engine.

When you remove the airbox you also reduce the spitter. No splitter nothing to return. And nothing to return means you can cap the engine connection at the front.

The only air actually builds up as a black residue in your throttle bodies. Your air intake will be cleaner an steadier when you block those 4.

Now you only need something to Not dump the oil on the street. you can do that with a catch can.

Of course this is for an older K1100 that has no airmass sensor.
It does have an airtemp sensor in the airbox but no airmass sensor. The airtemp sensor you need to relocate to the throttle body.

In my post a little bit up you find pictures of my throttle bodies and you can see the hose connections capped and the bach of the airtemp sensor

Hope this helps

[Mill]

EDIT: CONTINUE READING FORM TO UNDERSTAND - Mill

It transport an air oil mixture that comes from the carter due to over pressure, Do you mean air / fuel mixture?

And does this not effect the fuel/air mixture, you go on to later talk about a the The only air actually builds up as a black residue in your throttle bodies, does this mean that you have to clean your carbs more often or is there a solution to fixing this black ressidue?

If possible would it be better to take the 4-way hose and add it into the catch can at some point? (see below) Or what is officially come out of it the 4-way hose, is the thing I am not understanding.

I am assuming you would need a pcv or some sort of double check valve in before the catch can to make sure there is no back pressure.

IMG_3453.jpg (60.48 kB . 768x576 - viewed 547 times)

[Reinier]

"The only air actually builds up as a black residue in your throttle bodies," this was a typo or auto correct mistake. Let me try again.

In you drawing there is the crankcase breather. When the engine runs and the cilinders move there are moments of high air pressure the crankcase breather is to get rid of this pressure.
Because the engine is lubricated with oil and is hot a mix of air and oil vapour comes out of the crankcase breather.

In the original setup this mix goes through the splitter that sits in the airbox. This reduces the amount of oil in the mix. The remaining air and oil vapour mix goes through the 4-way hose in your throttle bodies. A K1100 does not have carbs. In time this mix  builds up in your throttle bodies as black residue.

After you remove the 4-way hose and block the connections to the throttle bodies only air that comes from your new air filters will pass through the throttle bodies and no more oil. So the stay clean.

Your drawing is good except 1 thing. Remove the 4-way hose.

[Mill]

I understand!

The 4-way is the connector for entry, not exit.

The reason I thought they were there were some sort of BMW engineering to sync airflow evenly though the carbs to alleviate pressure differences or something, but that is not the case at all rather its just oily/dirty air going to carbs to be re-burned. I will be blocking these off.


On a side note, did you get your 40mm intake manifolds from kpartsholland? or a different site? $226/€209 is quite expensive for the rubber and intakes

Dankje