I've got an RT3 that is a bit of a basket case that I want to use as a vintage MX bike, a pretty casual vintage MX bike to be clear as I am old and slow these days, but the bike came with no air box at all it just had a cheap pod filter on the carb. Normally I'm not a big fan of pod filters. My primary use for this bike is a couple times a year at a track that is mostly deep sand, so dust is for sure an issue, mud is not. Maybe the pod is fine? Or what else is better? The obvious thing to do is just use a stock rt3 setup but it looks like they're not so cheap especially for the rubber boot part and I'm not sure about availability of the actual filter element. If that's the way to go I'll go for it but is there some other alternative that is cheaper/more available/flows better/filters better/easier to service or some other thing that makes it the better choice?

Suggestions welcome. 

A little bit of modifying or fabrication is no problem if there's a good reason to do it. 

 

Mums best cooking pot does the job. Think i've got an "86 KX125 filter with cage in it by memory but did have a big K&N.
photos.app.goo.gl/yHo7eYmCyuB9TAhU6
That was a long ago pic & its grown shorter legs since then to keep it more in class for the vmx grade it fits best with.
In saying 'that', i'm too old to cut the mustard nowdays haha, Just scare myself down the farm once in a while.
Current setup below.
photos.app.goo.gl/yx45UwXDBs2aNzq58

Clauss Studios do a repro filter box to carb hose for $49 and air filters are still available from Yamaha (the last one I bought came pre-oiled).

Airboxes turn up on fleabay etc from time to time.

If you find an original filter box '& cage' then this type of filter is good oiled up for dusty conditions.
www.trademe.co.nz/a/motors/motorbikes/pa...r/listing/4711354797
Or just search for them by number NU-2201 [Uni Filter]
Here's one below. Looks a little like it might have the cage with it but i very much doubt it. Probably unfold it & sit the cage in then fold it over top & bottom to meet in the middle inside. "Guessing'
hvccycle.net/yamaha-dt-2-rt360-air-filter-uni-nu-2201/
 

So... The stock air box appears to be the sensible choice. 

But...

I have to admit I'm a little intrigued by the cooking pot. What exactly did you do there? I could see doing something like that for style points. 

Upon further investigation, my bike has a 34mm carb with a rubber carb spigot/boot/whatever you want to call it. The wrong one, hackishly installed.  I ordered a new mikuni rubber boot of the correct size but, then realized it looks like the stock rt3 would have a spigot mount 32. I think. The old parts books aren't super clear. So I don't think the stock carb to airbox hose for an RT3 would even fit on this carb. 

Certainly I could go find a stock carb but I'm having a hard time getting excited about searching for a few hundred dollars worth of carb and airbox to...kinda...downgrade. Especially since the plan is to eventually port this thing to more like rt2mx specs and use a cdi of some sort.

The "it just works" Factor with be nice though. Not sure. 

Then there's this nice pot in the cupboard that I keep eyeing up...

Mine has an rt2mx top end currently but only a modified std head machined until hit the fin. Not the proper exhaust so ended up putting a washer in the port to knock the top end & try to spread the power. It's a mad thing so might go back to a std cylinder. Getting too old to fight it. I have a vid somewhere up here I might bore you with seeing were talking similar stuff. Video needs dragging along as a bit distant in the paddock.

I'm into it, let's see the vid!

Also interested in any detail pics you have of the cooking pot. 

Yep stopped raining so i'll get some pics closeup of the pot.
Here's one video from about a year ago. Just drag it along to get it close to the camera bit.
Wanted to link it to previous page so as not to clog up your post but couldnt find it.
No very exciting sorry & can't realy let it off around that track. If you get off in the grass it's as slippery 'as'.

I love it. Looks like it goes pretty good. That looks like a longer travel setup than I'm scheduled to seeing on a bike from that era. The races that I'm planning to do have very informal rules but 7/4" suspension travel is one of them. But no rules against cooking pots.