DIY - Air Filter Retrofit Kit

[LeDude]

I thought I would share this with those of you that may be interested in putting together a retrofit kit for your OEM air filter.

I finally decided to do something about it after my third OEM filter, I just hate its wasteful design.

This easy DIY walks you through the step by step process of manufacturing a simple retrofit kit for a used OEM air filter.

You can build 4 retrofit kits for under $9.00, using the carcass of an old OEM filter, that's like $2.25 per kit.

I used the paper element from an automobile air filter similar in size and overall characteristics.

Here is the link to the DIY for now, should have the DIY video out by Sunday.

DIY - Air Filter Retrofit Kit

Here are a few pictures:

[jenkins]

I see no reason you can't use it on the 400, also. Tks, LeDude!! Jim

[LeDude]

I see no reason you can't use it on the 400, also. Tks, LeDude!! Jim

I am not at all familiar with the 400...the retrofit design principals should apply equally if it has a similar air filter.

[Dave_J]

I made my own years ago using "UNI" green foam and RTV.

[Max T]

This is how I Made mine

[LeDude]

This is how I Made mine

Nice job, I like the metal clip idea, I may have to borrow that for my second generation retrofit kit.

[Valerio]

LeDude:

I think it's more convenient to buy that "Uni" green foam that is used
for filters, similar to lawn mowers, etc.

I purchased a roll at the local foam shop for dirt cheap and I used it for my 400 b/4 buying
a 650 in '09.

With this product you would just cut to fit inside the frame, insert and voila ?????

....My two cents. I already did this several times on the 650.

Valerio

[LeDude]

Just finished uploading the DIY video for the retrofit kit.

[LeDude]

... I think it's more convenient to buy that "Uni" green foam that is used ...

I wanted to stay with a paper element like the one used in the OEM filter, the folks at Suzuki would have used
an all sponge filter if they deemed it to be more efficient.

I am sure both solutions would work equally well...

[born1928]

Great work Le Dude. I was hoping something like this would spring up on this forum. There was a similar project on the Honda Pacific Coast site which I used as a substitute for the OEM filter on my PC. The main difference was the addition of caulk around the perimeter of the DIY filter. May not be necessary with your method. When it's filter change time I will use your idea.

[LeDude]

... The main difference was the addition of caulk around the perimeter of the DIY filter. May not be necessary with your method. When it's filter change time I will use your idea.

I went through a few design alterations before deciding on the foam frame, it has proved to be the most reliable thus far, stays in place well and puts enough pressure on the paper element to hold it in place via friction.

I thought about using some sort of sealant, but in the end after 1k miles of testing it became clear that the foam frame was going to do the job.

One options was to put some kind of sealant or hot glue along the curved edges of the paper element before inserting it into the foam frame, it turned out to be too messy and didn't work very well, limited one's flexibility when it came time to adjust the paper element inside the foam frame.

the foam frame fits very snuggly against the edges on the inside of the air filter where the old paper element used to be. I tried to blow / suck some dirt through the setup but nothing made it past the foam or the paper, and I used a very generous amount of small debris.

I made 10 of them and should be set for the next 50k miles, I am going to change my air filter every 5k miles when I change the oils on the bike.

let me know how it works out for you.

[poldark]

Not quite as budget conscious as your excellent solution, but I'm just waiting for this EBay purchase to arrive.

At the price I thought it was worth a shot, not 100% till I've dismantled existing filter but having had a quick look I'm hopeful that this would near enough just slot straight in (200mm x100mm x15mm).

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250811447855&ssPageName=STRK:MEWNX:IT#ht_1410wt_905

Any thoughts about whether the claimed airflow increase will be something the ECU can accommodate, or could this have any issues to engine longevity because it may end up running too lean.

I've assumed (dangerous!) that any airflow increase would be relatively small (despite marketing claims).

[poldark]

Bit too early to say but on a short test ride I thought (placebo?) it rode a bit smoother, but then the old filter was pretty grubby. Either way it cost £2.49 and a bit of time to remove the old paper insert and trim the glued remains, plus trim the small amount to get the off-the-shelf piece to fit. Next time an easy swap out and saves tons on either OEM (£30) or Pattern filter (£20).

Old filter -


Paper removed and trimmed -


Supplied foam piece trimmed and inserted -



I don't have anything specifically holding the foam in place, but I made sure to not cut it too small, so I'm expecting it to remain in situ, did a quick check after the test ride and all fine. Should I be worrying it somehow works loose, given the direction of the airflow I can't see it being a danger?

[LeDude]

Bit too early to say but on a short test ride I thought (placebo?) it rode a bit smoother, but then the old filter was pretty grubby ...

looks good, I doubt that the foam will work its way up, especially with the fuzzy stuff left behind by the old filter on the sides ...
you can always add two retaining clips like max-t did, very easy to do...

[poldark]

Yes just paranoia on my part I think.

I have to say I must have spent half an hour with my wife's best nail scissors trimming off the excess "fuzzy stuff" as I was worried it would get sucked in, so there's not too much there but as you say it 'll actually help keep the new foam seated.

[NormanB]

My word,I thought I was cheap!
Much as I admire this innovative initiative, personally I would be nervous of following suit.
My concern is the potential bypassing problem. Not sure how we could go about measuring or even if it is practical to detect a true pressure drop, but it would involve drilling and mounting stubs to hook up a manometer.

Never mind look forward to the DIY oil filter.

[poldark]

Maybe I didn't make it clear but the "foam" is motorbike air filter specific replacement material with I suspect greater filtering capability than the original. I have concern on airflow and eventual air/fuel mix, particularly as mine is an early bike with no Lambda sensor on the exhaust (IIRC).

The only danger to me is it runs too lean and may cause damage long-term, would appreciate any views.

[LeDude]

was looking at your pictures again and a thought popped into my head.

You may want to use some of the scrap pieces and cut them width wise and put them under the big piece to make the top of the
foam flush with the rim of the air filter carcass... that way, nothing can get in there and it won't act as a trap for unwanted debris.

[poldark]

Was looking at your pictures again and a thought popped into my head.

You may want to use some of the scrap pieces and cut them width wise and put them under the big piece to make the top of the
foam flush with the rim of the air filter carcass... that way, nothing can get in there and it won't act as a trap for unwanted debris.

That's a good thought, the only worry for me is by doing that it will expose the remains of the original filter at the lower section on the housing. At the moment the exposed part is at the top, which is "above" the filter so any loose bits wouldn't get sucked into the engine.

I hope with all my nail scissor efforts there aren't any stray bits of fluff, but I sorta like the fact the new foam is flush at the base of the holder sealing it neatly against the mesh underneath.

Hope my logic makes sense, appreciate any thoughts you have on the air/fuel mix by using air filter foam rather than OEM filter, I'm not risking any engine issues am I?

Thanks for your inspiration and excellent maintenance materials.

[fred122333]

I really like the idea of making our own replacement air filters. However, when I looked for air filter material, I find all kinds of material rated 35 ppi, 40 ppi, 50 ppi, 65 ppi. So, anybody know which ppi material I should acquire.

Thanks for the great ideas......and, keep em com'n.

[poldark]

Perhaps little use as this is a UK supplier, but I just called RamAir who supplied the filter piece I used (EBay link above) and they advised the structure has 2-tier make-up.

10mm of 45ppi material then 5mm of denser 60ppi. They highlighted that the key factor in any filter is it's flow density (ability to stop airborne particles) and were proud of the fact that they have a patented dry oil facility so achieved 99.4%, whereas average paper filters start at 81% and reduce as they clog up.

No idea how accurate these claims are, but I basically spent £2.49 instead of £20/30, it runs well and I'm happy.

But when my engine blows up you can all laugh at me!

[Bazza]

Uni Filters are madein a factory unit about 10km from me so I rode over to buy some of the "real" filter foam for the mod.
Guess wot???
They wouldn't sell it to me, saying the extra airflow could weaken the mixture and cause burnt valves!
Perhaps they were'n aware that Burger has EFI cos I reckon EFI is clever enough to compensate for the additional air.
Anyhow, I never got around to it. Paper mod looks good.

[LeDude]

... They wouldn't sell it to me, saying the extra airflow could weaken the mixture and cause burnt valves!
Perhaps they were'n aware that Burger has EFI cos I reckon EFI is clever enough to compensate for the additional air. Anyhow, I never got around to it. Paper mod looks good.

That's good information to have, thanks for sharing.

[Dave_J]

... They wouldn't sell it to me, saying the extra airflow could weaken the mixture and cause burnt valves!
Perhaps they were'n aware that Burger has EFI cos I reckon EFI is clever enough to compensate for the additional air. Anyhow, I never got around to it. Paper mod looks good.

That's good information to have, thanks for sharing.

I made my own air filter using 5/8 " UNI green foam. I dident blow up the engine or burn any valves. Bazza, I still have some but post to you would be too much.

[Bazza]

Thanks for your kind offer Dave but you're right about the freight, I've just bought some stuff from a couple of different shops in the US, had the items sent to "Bongo" where they cosolidated the packaging and air freighted it to me (DHL), cost.......wait for it,,,
$159 USD, takes the shine off buying in the US even though our dollat is about $1.06US.
Regards.