Bmw R51/3 early air filter

[Darrens8560]

Hi I’m looking for some help, I have a 1951 bmw r51/3 and has an early style air filter housing on it but unfortunately not air filter. I have scoured the internet with no luck, seems to be extremely RARE.

I was wondering if some member on here had one that they wouldn’t mine taking a few measurements from. My intention is to try and make some that sort of resemble what would have be originally fitted. I have attached a photo to show what it looks like.

If anyone could help it would be greatly appreciated

[Darrens8560]

Photos

[wa1nca]

Same as my 54 51/3
#13
https://www.bmwclassicmotorcycles.com/p ... art-one-5/
I couldn't remove it without destroying the metal filter mess
I think is was met to be cleaned not replaced
Soaked it in gas, compressed air,let it final dry under the sun

Others should be able to confirm
Tommy

[vechorik1373]

The filter in the Knect air filter was of the permanent type. It was meant to be washed out with a solvent and reused.
However, I have seen them so plugged up (from unthinking owners who spray painted the filter) or the 65+ year old filter material completely disintegrated and crumbling and the pieces getting sucked into the engine.

How to fix it? This was the best solution I have found to replace the filter after you remove the screen and what is left of the old filter material.

This is sold at Lowes, it is 3m universal air conditioning filter material, (Item #552965 Model #LOWESCTF-12) that is easily cut with scissors, to any shape you want. I will caution you, that if you get overzealous packing this filter with TOO many layers, it will become more restrictive than the original air filter. And consequently, you will find that suddenly the engine runs WAY too rich due to the overly restrictive air filter. A single layer should do the trick.