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My 10cts

  • <i class="fa--xf fal fa-check "><svg xmlns="http://www.w3.org/2000/svg" role="img" aria-hidden="true" ><use href="/data/local/icons/light.svg?v=1758297946#check"></use></svg></i> Discussion starter Discussion starter Petrus
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Google maps, Michelin map enjoying morning coffee.
Wrote some orientative road numbers and towns on the masking paper. Stuck the paper on my trousers to make it less sticky and then on the gas tank.
Michelin map in charming´s little rucksack.
Will top up with 98 in the village up the road.
Still not decided on which hard top to don. The puddin´basin leaves the ears free so I can hear way more but it is also a lot more tiresome.
 
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And back.
Was véry windy so donned the jet model.
Added 10.2 l. 98.
Seems to run smoother with less ´mechanical´ noise when opening up from low revs.
Tanked nigh 11 l. 95 under way.
And the noise increased. Plus it pulls less smoothly.

For reference perspective:
- The bike is stock save for exhand because aust flap servo delete.
- Two up, through switchbacks, about 7 to 10% uphill, from 1500 rpm in third. Noticeable difference on 98.
- Accellerating from 100 km/h, 2200 rpm, in 6th. Obviously too much wind noise to notice an audible difference but it pulls smoother.

As I observed nigh all of my riding involves two up and mountains so 98 it is.

Had not expected it to be this clear. Thought it would be marginal and indicative for when opening the intake.

Another prespective;
www.cycleworld.com

Why Only 9.6 Compression On The BMW R 18?

Why do large, slow-revving engines have lower compression ratios than those seen on multi-cylinder engines with smaller bores? Kevin Cameron simplifies the answer.
www.cycleworld.com www.cycleworld.com
(and the need for a dense dealer network is a góód thing?? )
 
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Noelpolar said:
On 98 and low revs but high throttle.... told you so..... haha

Bren tune will add about the same again.
Click to expand...

Makes technically sense but it is more pronounced than I expected.

Not going Bren flash.
Servo delete and a bit later on more air in wil have to do.

Bottom line is that especially for anyone dropping in a sports filter or in any other way modfying the flow, 98 offers smoother running from low revs.
 
Fitted the homage saddle.
Have an extra high buddy and a luggage rack so looks are compromised but the saddle - pillion cushion combination does look vére vintage. Also the carming company makes it worth it.
Replaced the M8 torx with 5 mm shorter M8 hexogonal and thas was a doddle.
Not convinced by the saddle yes. It is higher so less angles in my legs but it is also a lot harder than the original foam.
We´ll see how it pans out on the move.

image_2025-09-27_111632384.pngimage_2025-09-27_111704774.png
 
My son was over from uni and I have asked him to 3D print the ´1800´ engine plaques with open honeycomb back ground. The idea is that this will be extra air intakes. Should be about 20-30% (depending on logo design) more intake surface.
Imo it is essential to add intake surface if a sports filter is to be fitted.
My plan is to fit a Sprint sports filter and modify or delete the filter cover. Deleting would reduce turbulence but also increase intake noise.
Not fitting a metal frame. Just a dab of silicon will keep the filter element put.

The stock programming will adjust the mixture for the extra air flow. I.e. a bit more oompff with the same mixture parameters.
Roland Sands did dyno runs and got up to 108 hp on the stock program with open intake and exhaust.
Obviously nothing like that with just a bit more air in and exhaust flap delete but it is the perspective that it will work and have effect.

No, Bren tune does not have the same effect. It will however make use of the same extra air with more optimal parameters.

To be continued...
 
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Here some very good photos of the 2016 presented R5 homage which is amazingly fortelling the 2019 R18 concept and subsequent 2020 R18 FE. They basically showed the blue print less piece the resistance (engine).

www.motorbox.com

BMW R5 Hommage: guest star a Villa d'Este

Al #Concorsodeleganza di #VilladEste sfila la #BMWMotorrad #R5Hommage, che celebra gli 80 anni della #BMWR5
www.motorbox.com www.motorbox.com
 
Below a photo I ´like´ a lot.
It shows that the intake slots in the front cover have a serious restriction behind them. The black platisc boxes are noise reductions with a narrow entry, AT the back they have the rubber snorkles attached which go to the filter housing lid.
It shows just hów restricted the air intake is: It sucks, literally. Every pressure drop in inlet tract = less BMEP = less torque/power....

image_2025-09-30_191722105.png
 
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Petrus said:
One advantage of this ´tuning´ that when periodic inspection comes, the original can be simply refitted to recurtail induction noise.

to be continued .....
Click to expand...
Not convinced on the use of a 3D printed plastic. They are more useful for short life objects. I understand that there are a lot of different materials available but just a word of caution.
I am currently looking at a 4 axis desk top CNC machine that could do that in metal. Just need to convince my colleagues that it is a good investment for doing prototyping.
If I convince them will let you know.
 
Red64 said:
Not convinced on the use of a 3D printed plastic. They are more useful for short life objects. I understand that there are a lot of different materials available but just a word of caution.
I am currently looking at a 4 axis desk top CNC machine that could do that in metal. Just need to convince my colleagues that it is a good investment for doing prototyping.
If I convince them will let you know.
Click to expand...

Thanks @Red64 Been using various materials for some 6 years now and indeed UV and temperature are issues as is material fatique but things have evolved húgely. Furthermore it si just side plates and can have him reprint a set.

@Noelpolar good idea if a sports filter is fitted and the lid removed or opened. You have no?! So have at it!
Looking at the air entry, the side openings should make a difference.
It is a simple thing to do at no cost and as easily reversible.
 
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Ordered the Sprint sports filter

andreanimhs.com

Sprint Filter P08 Filtro de Aire BMW R18

Sprint Filter P08 el filtro de aire de rendimiento estándar, ideal para el uso legal en la calle o p...
andreanimhs.com andreanimhs.com

Según un estudio independiente llevado a cabo por la Universidad de Gales Trinity St David, el tejido de poliéster P08 de Sprint Filter, proporcionó el mejor flujo de aire de cualquier filtro entre todas las marcas, incluyendo los filtros de "carreras" de la marca líder. El filtro Sprint P08 utiliza un medio filtrante especial de poliéster con un diámetro de hilo de sólo 70 micras. Su patrón de tejido único puede filtrar los residuos tan pequeños como 80 micras.

In other words, the fibers are thinner, thus less fibers and more holes per cm2, meaning less restance. The weave is also slightly less fine; slightly bigger holes, again less resistance. All in all a lot less air resistance and only marginally less fine filtering. Better filtering than K&N (DNA) yet less restricting. All that without the @##@@ filter liquid.

Should about reduce flow resistance by half. No, that is not saying double the flow.
Also the reduction in pressure over the filter depends on the flow. The more air flows trough, the more advantage a sports filter has.Thát illustrates that to make full use of a sports filter the flow tó it should be as unrestricted as reasonably possible.
Í think add another entry from the outside and ditch the filter cover.
Ah and when fitting open side plates will try round the edges of the apertures. It is after all about marginal gains so best max the margins :ROFLMAO:
 
Off for a weekend of Vespa mayhem. The route written on paper masking tape stuck on the steering cover. Would do the same route on the R18 and due to the narrow twisty rural nature, would do marginally higher average. Still missing the big one already. It is not the same flogging the 125 over the hills.
One caveat; tonight we will go up to the Santuario de la Virgen de Araceli (Lucena -Córdoba) with some 300 scoots more and thát would be simply a nono with the bruiser.
 
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