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1Back to top Go down   Milling some new inlet manifolds  Empty Milling some new inlet manifolds on Tue Aug 13, 2019 3:47 pm

Tommy2305

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Since my Inlet manifold is leaking, I plan on milling som new ones out of billet aluminium with silicone hose, because why not Milling some new inlet manifolds  1f609 Wink
Does anyone know if it is going to affect the engine in a bad way, that the internal angel/contour is made differently? 
I can only think that it will optimize flow, but maybe that will result in a lean mixture somehow?
The 3D drawing is my idea, compared to the 2D drawing which should be more or less like the original.

The whole idea came from this guy who casted his own at home and I really liked the idea 
https://bmwk100k75.weebly.com/air-leaks.html

Close up pictures of an inlet manifold from different angles would really be appreciated! Even an old knackered one bounce 

And at last, can anyone confirm the measurements on the last picture? 

Milling some new inlet manifolds  Img_1111
Milling some new inlet manifolds  Img_1110
Milling some new inlet manifolds  Skzirm10

    

2Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Tue Aug 13, 2019 5:05 pm

charlie99

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neat idea

perhaps these pics from an unmolested rubber will help ?

Milling some new inlet manifolds  20190824

Milling some new inlet manifolds  20190825

Milling some new inlet manifolds  20190826

don't forget , the design of the rubber is to interface the throttle body inside diameter to the inlet port

generally without too much change in diameter (although one can see that bmw did do some change in diameter )

the diameter of the port side should match the head  and on the rubber adaptor this is easy to achieve

Milling some new inlet manifolds  2013-111

good luck


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

3Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Aug 14, 2019 6:54 am

Dai

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You need the slight internal cone shape because it accelerates the mixture into the combustion chamber.


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'83 K100 upgraded to K100RS spec
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4Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Aug 14, 2019 7:17 am

Tommy2305

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Thank you Charlie, i really apreciate your effort with the measurements and pictures! And i Think Everyone like unmolested rubber better 😂

I think the only messurement i need is the total height and Also from the top down to the groove where the throttlebody sits om top of (internally) 😊
If you have the time to do it i can’t thank you enough


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5Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Aug 14, 2019 7:20 am

Tommy2305

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Maybe you misunderstood me dai, i’m going to change the coneshape to different angle which should help the engine pulse



Last edited by Tommy2305 on Wed Nov 06, 2019 11:11 am; edited 1 time in total


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6Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Aug 14, 2019 8:04 am

charlie99

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hope this helps

Milling some new inlet manifolds  20190830

Milling some new inlet manifolds  20190831

cheers


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

7Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Aug 14, 2019 12:50 pm

Tommy2305

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Thank you, this is a big help! I really appreciate the effort 😃👍🏻


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8Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Thu Sep 05, 2019 11:54 am

Tommy2305

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@charlie99 wrote:hope this helps

Milling some new inlet manifolds  20190830

Milling some new inlet manifolds  20190831

cheers

Charlie do yo know the diameter of the inlet port? I might adjust the diameter so I fit directly on to the inlet port to achieve a good flow. Also do you know the diameter of the o-ring which is seated under the inlet manifold?

best regards


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9Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Thu Sep 05, 2019 3:30 pm

charlie99

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there is no ring under the rubber on k100 8 valve types .that I have seen ..I think there is one under k1100 - k100 16 valve types , because the rubber integrates the injector as well .

if you look at one of the earlier pics I posted in this thread ...you could guess the port diameter ....the one shown maybe about 1/2 a mm larger than stock  because I rework the inlet path to take out irregularities , get rid of the short turn lip and mod the valve guide  for better flow , which works well .


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

10Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sat Sep 07, 2019 5:02 am

Tommy2305

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@charlie99 wrote:there is no ring under the rubber on k100 8 valve types .that I have seen ..I think there is one under k1100 - k100 16 valve types , because the rubber integrates the injector as well .

if you look at one of the earlier pics I posted in this thread ...you could guess the port diameter ....the one shown maybe about 1/2 a mm larger than stock  because I rework the inlet path to take out irregularities , get rid of the short turn lip and mod the valve guide  for better flow , which works well .
Okay Thank you. I might make these ones with a o ring under the bottom. But I think I will make the smaller diameter in the inlet manifold around 30.50 mm then, to avoid having a big edge which will prevent flow.


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11Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sat Sep 07, 2019 5:31 am

charlie99

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that sounds about right

Milling some new inlet manifolds  112350


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

12Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sun Nov 03, 2019 7:06 am

Tommy2305

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So here is a quick update on the manifolds, all four are milled in aluminum. They still need some work and which can only be done when I have the correct measurements of the inlet port. 

I will keep updates coming

Milling some new inlet manifolds  Img_1114
Milling some new inlet manifolds  Img_1113


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13Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sun Nov 03, 2019 7:17 am

Tommy2305

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@charlie99 wrote:that sounds about right

Milling some new inlet manifolds  112350
I saw your thread with you build and it is really amazing Charlie... The part with the throttle bodies airflow measuring was very interesting and I might improve mine as well. Do you think removing the ridge inside the throttle body will be worth it maybe with a bit of polishing? or will it lean out the mixture if the engine breaths more air in?


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14Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sun Nov 03, 2019 4:02 pm

charlie99

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I don't think that the ridge removal will lean out the mix , but will act as some disturbance to flow with the change in diameters at that one point

I guess the ideal would be to have a nice smooth internal tube of constant diameter , rather than a gap between diameters , if that makes sense .

the machining looks great in your pic,  well done , wish I had the skills and resources for something similar .


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

15Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sun Nov 03, 2019 7:43 pm

brickrider2

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Beautiful work, Tommy.  That's real eye - candy! cheers


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16Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Mon Nov 04, 2019 1:57 am

jbt

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Changing the venturi angle will affect the engine, probably in a bad way. There's no chance it improves its performance if you don't adapt the following tube in shape and diameter to fit these new features - and if you don't use a flow bench to test it.
Anyway, as on your K100 has an injection port very close to the valve, it's pointless to create turbulences before in the inlet manifold as there's no fuel to be mixed with air at this place.
Besides this, the rubber manifold provides vibration insulation to the whole injection system. Expect rapid wear and problems with the internal card of the flowmeter.

    

17Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Mon Nov 04, 2019 4:49 pm

Tommy2305

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@charlie99 wrote:I don't think that the ridge removal will lean out the mix , but will act as some disturbance to flow with the change in diameters at that one point

I guess the ideal would be to have a nice smooth internal tube of constant diameter , rather than a gap between diameters , if that makes sense .

the machining looks great in your pic,  well done , wish I had the skills and resources for something similar .

Thanks, it is never too late to learn Wink I haven't pulled the throttlebodies of yet, but I'm able to mill out that ridge if I decide and then lightly polish it to make it smooth. I guess that's more accurate than with a Dremel. I will make everything as smooth as possible with no ridges or edges which will prevent flow.


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18Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Mon Nov 04, 2019 5:02 pm

Tommy2305

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@jbt wrote:Changing the venturi angle will affect the engine, probably in a bad way. There's no chance it improves its performance if you don't adapt the following tube in shape and diameter to fit these new features - and if you don't use a flow bench to test it.
Anyway, as on your K100 has an injection port very close to the valve, it's pointless to create turbulences before in the inlet manifold as there's no fuel to be mixed with air at this place.
Besides this, the rubber manifold provides vibration insulation to the whole injection system. Expect rapid wear and problems with the internal card of the flowmeter.

I'm not focusing on the flowmeter for now, not sure if that's restrictive anyway. My goal is not to create turbulens, but better breathing.
When looking down in the original inlet manifold you can see the inlet port is slightly smaller than the inlet manifolds exit, which create an edge which result in "bad" flow. 
The plan is simply to make the internals smooth all over since I have nothing better to do. lol!


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19Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Mon Nov 04, 2019 5:41 pm

jbt

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To make your engine breath better, first give him big lungs, then you'll consider milling the teeth to enlarge the mouth. This engine is filled only by aspiration and the only restriction is the flowmeter, not the manifolds nor the air filter. It's not because there will be a shiny welcoming manifold that more air will magically run into it, it's all about pressure & couter pressure.
Without flowbench measures, you can be sure to lose more than you gain modifying the intake. And if by chance, you manage to increase the amount or the speed of the air getting inside, how will you adjust the fuel in adequation?
The direct and big admission ports are designed for high rev super square engines. What a k100 engine is definetely not -and will never be.

    

20Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Nov 06, 2019 11:44 am

Tommy2305

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@jbt wrote:To make your engine breath better, first give him big lungs, then you'll consider milling the teeth to enlarge the mouth. This engine is filled only by aspiration and the only restriction is the flowmeter, not the manifolds nor the air filter. It's not because there will be a shiny welcoming manifold that more air will magically run into it, it's all about pressure & couter pressure.
Without flowbench measures, you can be sure to lose more than you gain modifying the intake. And if by chance, you manage to increase the amount or the speed of the air getting inside, how will you adjust the fuel in adequation?
The direct and big admission ports are designed for high rev super square engines. What a k100 engine is definetely not -and will never be.
No one mentioned high revs. Actually i didn't know the flowmeter was the restrictive part, I haven't found that written anywhere. 
As I said in the post, all of this work is done because my intake is leaking, and while I'm at it why not make it shiny and smooth out the internal edges. The changes I'm making are tiny. Very tiny. I'm not expecting any horsepower gain, but a nice running engine.


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21Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Wed Nov 06, 2019 1:09 pm

Laitch

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@Tommy2305 wrote:Actually i didn't know the flowmeter was the restrictive part, I haven't found that written anywhere.
That would depend upon how the word restriction is defined.


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Milling some new inlet manifolds  Usa-lo10
    

22Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Thu Nov 07, 2019 4:12 am

charlie99

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@Tommy2305 wrote:No one mentioned high revs. Actually i didn't know the flowmeter was the restrictive part, I haven't found that written anywhere. 
As I said in the post, all of this work is done because my intake is leaking, and while I'm at it why not make it shiny and smooth out the internal edges. The changes I'm making are tiny. Very tiny. I'm not expecting any horsepower gain, but a nice running engine.

 thats the aim ...to make the intake a smooth flow ...  keep at it !!!


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

23Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sat Nov 09, 2019 5:16 am

Tommy2305

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@charlie99 wrote:
@Tommy2305 wrote:No one mentioned high revs. Actually i didn't know the flowmeter was the restrictive part, I haven't found that written anywhere. 
As I said in the post, all of this work is done because my intake is leaking, and while I'm at it why not make it shiny and smooth out the internal edges. The changes I'm making are tiny. Very tiny. I'm not expecting any horsepower gain, but a nice running engine.

 thats the aim ...to make the intake a smooth flow ...  keep at it !!!
Yes, I will proceed  Milling some new inlet manifolds  112350  But I'm thinking that ridge inside the bottom of the throttle body might be made to create turbulens inside the cylinder to mix the air and fuel faster. Maybe it's a bad idea to remove? I'm thinking it is there for a reason


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24Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sat Nov 09, 2019 6:06 am

charlie99

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no the rubber is made to adapt the bore of the throttle bodies to the inlet port which are different diameters ...also gives some vibration isolation but not much as the whole plenum and air box and afm are also rubber isolated multiple times


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMilling some new inlet manifolds  Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

25Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Sat Nov 09, 2019 1:55 pm

jbt

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@Tommy2305 wrote:But I'm thinking that ridge inside the bottom of the throttle body might be made to create turbulens inside the cylinder to mix the air and fuel faster.
Do you really think that it would create  appropriate turbulens as the butterfly flap just above is much more disturbing for the air flow?
It's nonsens to worry about turbulens when it's only air in the tube at this place. The K100 injector is designed to aim the back of the valve, which is very hot and vaporises instantly the fuel. Once it spits at the optimum instant, once it spits when the valve is closed and the engine is asked to wait the next cycle to swallow the mixture when the valve opens. It's pretty neanderthalian as an injection system, but it works. Yet it will never suit nor allow a performance engine, so don't search any improvement in admission line design, it won't improve anything since this L-jetronic is fitted.

    

26Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Tue Jan 07, 2020 2:12 pm

Tommy2305

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I have been really busy, but here in the Christmas holiday I finally got the chance to work on the bike. 
I finished one manifold, to see how it would fit, and it was pretty good and the diameter goes from Ø35 to Ø31.45. The diameter is a little bit too small so I'm going to mill the smaller diameter up to 31.6, and make room for the injectors, underneath the manifold. 

While making those manifolds, i figured I might have to paint the engine and drivetrain, just to make everything look slick. Even painting the throttlebodies. 

Here is a couple of pictures:
Milling some new inlet manifolds  Img_1214
Milling some new inlet manifolds  Img_1215
Milling some new inlet manifolds  Img_1213[url=https://servimg.com/view/20089755/21] Milling some new inlet manifolds  Img_1218[/url]
Milling some new inlet manifolds  Img_1217[url=https://servimg.com/view/20089755/24]Milling some new inlet manifolds  Img_1220
Milling some new inlet manifolds  Img_1219 [/url]


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27Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Tue Jan 07, 2020 3:15 pm

92KK 84WW Olaf

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I see what looks like a Mini in one of those photos.....

Are you planning on pulling the head etc etc off the K an putting it in the Mini?


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1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 102,50 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell No 34,600 miles
    

28Back to top Go down   Milling some new inlet manifolds  Empty Re: Milling some new inlet manifolds on Thu Jan 09, 2020 11:59 am

Tommy2305

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@92KK 84WW Olaf wrote:I see what looks like a Mini in one of those photos.....

Are you planning on pulling the head etc etc off the K an putting it in the Mini?
It would definitely be a good project putting a k100 head on one of the mini's! I've seen a guy pushing 140hp out of the a-series engine with a k100 head  Very Happy  but I don't think I have the time at the moment, but maybe some day


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