New Owner- Definitive Airbox Answer?

[engineerk9]

First pic is my airbox at about 1,800km. I had been greasing the stock air fiter surround as suggested by the thread on ADV rider. That was not my problem....
Second pic shows the perimeter seal not even located within the recess, FROM THE FACTORY!
Third pic is Engenia's 3D printed filter frame mod (the part that forms the new filter "door frame" as seen from the very front of the air box, not from the air intake vent. Note the stiffening gussets he glued above the new air filter and the cutaway to increase airflow available to the filter surface.
Fourth pic is the white 3D printed air filter frame with wing nut to secure to the "door frame".
Have done 20,000km and checked it twice since initial modification - clean as a whistle.....
I keep 2 air filters on hand so a spare always clean & oiled ready to go, a 5 minute job to swap.
Best mod ever for this bike.View attachment 63828View attachment 63829View attachment 63830View attachment 63831

I'm very pleased with Errol's 3D frame etc

 

[nev..]

Not sure if this is the right place for posting this, but yesterday I checked the airbox to remove, clean and oil the Unifilter, only to find its rubber frame badly warped, and letting the air to bypass. This despite using the K&N filter grease. I reverted back to the stock paper filter, which has a more rigid rubber frame.

That's an interesting observation, because I found that the stock paper filter had a much more plyable rubber frame which would flex quite a lot, while the Unifilter rubber frame was much more rigid and less prone to deformation. Also, the stock paper filter is much more prone to being flexed when you push the filter frame into place. The bottom inside corner of the paper filter can become snagged on the inside of the airbox and as you push the filter tray in, can cause the paper filter to deform and for the rubber frame to lose contact to the filter frame and let unfiltered air past. Due to the design, unless you have a camera which you can feed into the air intake to look around the corner at the filter, you would never know whether or not it has made a good seal. If the bottom corner of the filter paper is dog-eared when you take the filter out, this is a pretty good indication that it snagged on the way in and caused the rubber frame to warp and let unfiltered air past.

 

[Ogre_fl]

FWIW I found the same issue with the UNI filter that wferrari did.
In the stock frame it badly warped/deformed to the point it was pulling out of the frame.
I seem to recall that it also did not fit well in the stock frame to begin with either.

 

[wferrari]

That's an interesting observation, because I found that the stock paper filter had a much more plyable rubber frame which would flex quite a lot, while the Unifilter rubber frame was much more rigid and less prone to deformation. Also, the stock paper filter is much more prone to being flexed when you push the filter frame into place. The bottom inside corner of the paper filter can become snagged on the inside of the airbox and as you push the filter tray in, can cause the paper filter to deform and for the rubber frame to lose contact to the filter frame and let unfiltered air past. Due to the design, unless you have a camera which you can feed into the air intake to look around the corner at the filter, you would never know whether or not it has made a good seal. If the bottom corner of the filter paper is dog-eared when you take the filter out, this is a pretty good indication that it snagged on the way in and caused the rubber frame to warp and let unfiltered air past.

I cannot vouch for the paper filter, although when I took it off the first time there was no issue with it, but the unifilter rubber is definitely softer, and provides far less resistance to lateral pressure, due to the lack a real inner frame, like the one used by the stock filter. My wild guess is that extreme heat may have something to do with this, as I don't recall it being this soft when I first bought it.

FWIW I found the same issue with the UNI filter that wferrari did.
In the stock frame it badly warped/deformed to the point it was pulling out of the frame.
I seem to recall that it also did not fit well in the stock frame to begin with either.

The stock filter is definitely a better fit to the frame compared to the Unifilter. That's why I had to use a lot of K&N sealing grease, but it was clearly not enough.

 

[blacki]

I pulled my Strada apart to check the airbox was not leaking. I was lucky; the seal between the upper and lower halves was in place, the paper air filter had let almost no dust around the edge where the airbox hasn't the missing lip, and at 10000km the inside was pristine. I decided not to cut away the wall which obscures about half of the Unifilter in Sussurf's third photo, since I had not yet decided between the Engenia solution or the pod mod.
While I was there I installed new shims to set the valve clearances at the max spec: 0.275mm IN, 0.425mm EX. The gaps always decrease. And a pair of NGK CR9EIX Iridium plugs. I won't be back here until 40000km.
I ended up installing Errol's 3D printed frame, using his recommended glue, 3M DP8010. I test glued polypropylene to ABS using a couple of other glues rated to stick PP and PE, but they didn't work satisfactorily. I ended up importing a 250ml dispenser of the 3M glue from the US at great cost, but it glues very well. Since the glue starts to go off within a couple of minutes after mixing with the hardener, before mixing the glue I rehearsed inserting the frame into the airbox at just the right angle so it seated neatly into its final position on the first approach. It fits very precisely, and seals perfectly. The glue goes firm and rubbery quite quickly, then sets much harder after about a day.
Since I had not cut away the internal wall in the airbox, to get air to the front part of the unifilter I cut two 25mm dia. round holes in the airbox filter cover and glued in a pair of black plastic elbows from an irrigation supply store, pointing downward to deter water from getting into the airbox. There is plenty of room between them and the fork leg at full right lock. After 2000km the filter has dust on the outside both front and rear, and there is no dust inside the airbox, so the solution looks good. Next farkle, a Cameleon chain oiler.
blacki

 

[gullywasher]

I had opened up my airbox with just a few hundred miles on the bike. While there was no leakage around the filter at that time, a little dust was coming in through the filter halves (there was actually no rubber seal at all between the halves like I've seen on some pics) and also from a hole drilled into the bottom of the box where a temp sensor was inserted into the box: no grommet or sealant of any kind, just an open hole with the sensor stuck through it.

I pod-modded the thing. It is the only "fix it and forget it" solution to the airbox in my mind.

 

[sussurf]

I pod-modded the thing. It is the only "fix it and forget it" solution to the airbox in my mind.

In your mind perhaps...
I wonder how your pod mod gets positive air pressure, where it gets it's air from & how your TB is enjoying that 90º elbow?

 

[DeLewis]

Unless I am riding in dusty conditions, I leave the airbox 'door' off with my pod mod - creates a semi ram-air effect and makes a considerable improvement on performance. When riding off-road, I install the airbox door with the pool filter sock pre-filter which GlitchOz came up with I think.

 

[sussurf]

So not being a smart arse but not exactly "fix & forget it" as stated. All I know is that after Engenia modded my airbox with the 3D printed filter frame & various improvements & LOTS of dirt riding, no dust is getting in at ll & I'm at 23,000k.
All I do is wash the filter & re-oil it from the original front airbox door. That's what I call "fix & forget it"!!!

 

[drzcharlie]

There will be no agreement on this. We have beat this freaking horse to death. Pick a fix or don't do a thing. It's your choice not ours.

 

[sussurf]

I agree Charlie & didn't intend to start another debate about this.
My point is that we want this forum to be as valuable a resource for TR650 owners worldwide as is possible.
Anecdotal evidence forms a large part of this intelligence pool but we have to be careful about making conclusive comments based on what "we" know for personal validation at the same time discounting other evidence of fixes/modifications that have also clearly been shown to solve problems.
All good...

 

[Mark_H]

Not wanting to start yet another Horse Flogging debate, as with any modification - YMMV
Some guys need, some want and some do not...

My take on the Pod Mod is similar -

Some guys found that they definitely needed to do it (or something similar)
Some guys liked the idea and wanted it - regardless of needing it or not.
Some guys might need it but do not really know or care.
Some guys think they do not need it.
Some guys have thought about it, checked and found they do not need it.
Some guys do not want it.

I am just one of those "some guys"

 

[glitch_oz]

In your mind perhaps...
I wonder how your pod mod gets positive air pressure, where it gets it's air from & how your TB is enjoying that 90º elbow?

"Air pressure" isn't even an issue, there's as much air as before ...and my TB seems to enjoy itself as well as that elbow.
No dust ingress or any other issues to report.
Just replace the Pool Sock Primary often...and/ or check filter foam regularly.
Fix and forget indeed.

 

[sussurf]

"Air pressure" isn't even an issue, there's as much air as before ...and my TB seems to enjoy itself as well as that elbow.
No dust ingress or any other issues to report.
Just replace the Pool Sock Primary often...and/ or check filter foam regularly.
Fix and forget indeed.

Brilliant Glitch, then read my next post.
Just agree there's more than 1 way to skin a cat...

 

[gullywasher]

In your mind perhaps...
I wonder how your pod mod gets positive air pressure, where it gets it's air from & how your TB is enjoying that 90º elbow?

In my mind, period. That is what I said. Not perhaps. I am not claiming it is the only solution, just the one that I am most comfortable with. I'm glad to hear the printed piece is working well for you. Sounds like a winner.

The air flow has to turn about 90° from its path to get into the throttle body with or without the elbow in place since the TB opening is positioned perpendicular to the flow of air through the box, so I don't see your point. If the TR had a ram-air effect creating "positive" airbox pressure, I wouldn't get dust leaking in between the shells. So I think I am good there as well.

 

[drzcharlie]

Like I said beating a dead horse.

 

[engineerk9]

Like I said beating a dead horse.

"flogging the dead horse"
To get a pressurised airbox, the connection between air box & throttle body needs to be sealed which it is in the original, but not in the Pod-mod, which was one of the reasons I went back to the 3D printed filter as per sussurf
Which also possibly explains why the fuelling is "richer" at the higher rpm when "in theory" airbox pressure is higher

 

[blacki]

I chose the 3D printed frame because maintenance is so easy. Without the original filter frame attached to it, the front airbox cover is very easy to remove, so is the Unifilter. No need to remove a lot of plastic to gain access to the pod filter.
The other reason is to leave the original airbox design intact. The voluminous airbox provides nearly still air at the TB. It uses volume that could otherwise be enclosed in a bigger fuel tank. Still air is at higher pressure than moving air (Bernoulli). Without the elbow, the column of air that has to be accelerated by the pressure in the airbox when the inlet valve opens is shorter and has less mass. The difference may be almost imperceptible, but that's the design principle. A longer column tends to give better filling and more torque at low revs due to the momentum of the air column, but less power at high revs. I need all the power I can get, to keep up with my mates on bikes with twice the power :-)
blacki

 

[PaulC]

The 3d printed frame will eventually let go, as we have seen

 

[sussurf]

Remember there's 2 frames that were designed.
The first was from I can't remember who in the US and offerred as an .STL file for printing at your local 3D printer. This one had failures.
The second was developed in collaboration with Engenia and one of his guru mates in Melbourne I think. It was designed much stronger and you could only buy the manufactured frames, not the print file.
Errol has fitted more than 25 of these around the country with no reported failures. Mine looks like it will outlast the bike.
So, again, lets be careful what we say & impart accurate information out there for TR650 owners.
Your options:
1) Do nothing
2) Pod Mod
3) 3D printed frame from the .STL file
4) 3D printed frame & airbox upgrade from Engenia