More Air Filter Pod Ramblings

I recently ordered these air filter pods from the Internet (cutting out Amazon, just to minimize business with them) before watching a bunch of YouTube builder videos that heavily criticized the quality of these type of cheap pod filters. Each influencer warned viewers avoid these cheapo filters. 

To be honest, I'm not sure why I ordered these since I already have pretty good foam Pods installed.

I was surprised to find that they were decent quality. The filter material was better than I expected and the sealing was fairly good compared to what I was seeing in those builder 'review' videos. I just wanted to throw out my 2 cents on the topic.

I also discovered that the opening wasn't too restrictive, so if spending less than $8 per POD is not too spendy for you, it's OK to give them a shot.

I was teaching myself to do some designing in Tinkercad and thought it might be a neat thought exercise to adapt these pod filters to use the rubber boots from the airbox for a nice smooth airflow into the slide lift ports on the CV Carbs of my cb750. 

Like other pod filter users, I discovered some sputtering when riding in a stiff cross wind as well as some slide flutter on hard acceleration without a downshift (low rpm acceleration) and I wondered if I could minimize that behavior with 3D printing.

Smooth transition into carb throat

It took a few tries, but it came out pretty good printed in PETG, I have no idea if this is at all useful but if this shows an improvement, I may also design and print a tube that extends into the filter area in an effort to tame the airflow even more....

Trim the airbox boots

Filters Oiled and clamped in place

Years ago, I was told the airbox boots were no longer available but I verified they could be purchased new before I trimmed them.  The boots for cylinder 1 & 4 ('Air Box Boot B' ) have curves in them to accomodate the narrower airbox placement/shape but that curve doesn't give me any trouble as far as clearance on installation goes.

When I last checked eBay, a full set of these boots were around $45 but the set I had in my old airbox sitting on the shelf would work (free) even though they were a little tattered from years of removals and installations.

It was low 50s this afternoon, but  I wanted to see how the bike behaved with this minor modification. They did not disappoint on a quick around the neighborhood loop. Once the bike warmed up, that low RPM slide flutter was practically all gone and acceleration was instant. I could hear a slight brief flutter but did not feel any hesitation.  

The cool air was giving me a slight hanging idle but nothing terrible and unrelated to this mod.

If I were to do it again I would:

• cut the boots longer and smoother
• use black ABS or Nylon filament (or maybe orange to match the original orange pin stripes on the tank).

EDIT: I can say that this is definitely an improvement after confirming there is no noticeable sputtering riding around local roads with stiff winds on the first really nice (but windy) day of the season. With a cross wind strong enough to push me side ways, the bike ran nice and steady.