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Discussion Starter #1
Ok so after purchasing a few different air boxes... a fiberglass thorsten, a carbon fiber thorsten, a squidskins moriwaki copy I finally decided to just modify the stock air box. After looking at these aftermarket boxes its great that they have more volume but that volume is also deceiving. I say deceiving because the entire throttle body assembly is part of that volume where as the stock air box they are not... so here is what I did... I disassembled the box, gutted it and put it back together... it is still a little heavier than the moriwaki copy and of course I dont know the volume but im willing to bet its just as much as the moriwaki! So here are the pics!!!
 

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Probably the best OEM airbox mod I've seen so far.
You used the Turn-One filter mount at the mouth of the airbox for easy filter cleaning.
 

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Discussion Starter #4
I still need to clean it up some more and I really want a custom K&N filter to fit the mouth. I think it turned out beautifully considering it was 2 hours in the garage and maybe 25 bucks in parts and tools to do it... I also clipped out the center piece in the frame that splits up the air between left and right air filters that no longer exist. Im hoping that once I am done this turns out great! Though its not something that was done all by its self to see if there were performance gains but I can be happy that I have reduced some weight, increased air flow and volume and can use this with my ETI fuel cell and it was in expensive... I should have just done this from the start instead of sinking over 1000 bucks into 3 different air boxes...
 

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Try checking out K&N panel filter number 33-2633
Some have used this for the Turn-One airbox filter instead of the supplied one.

Part 33-2633 Product Specifications

Product Style: Panel Air Filter
Height: 0.938 in (24 mm)
Outside Length: 6.375 in (162 mm)
Outside Width: 4.625 in (117 mm)
Filter Material: Cotton Gauze
Filter Re-Oiling Amount: 0.35 oz (10 ml)
Inner Wire: No
Top Style: Open
Weight: 0.6 lb (0.27 kg)
 

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Very cool!! I wish I would have seen this before I had my bike dyno tuned. What all did you need to put this together? I see the panel filter, did you put together the frame for the filter in your pictures?
 

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Discussion Starter #8
Its just screen, same stuff used for radiator protectors or vents.. I got it from Brett. The frame came with the stuff I got from brett and it just riveted into the box. Its meant for the turn one air box but with just a minor amount of trimming fit great in the stock air box!!
 

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Resons for not using the other boxes?

I'm curious why you do not care for the other aftermarket boxes. I suspect it is that they may not seal up tight and any gained positive pressure is lost. Am I right? If not, share a little wisdom to this new owner. Thanks, Rich
 

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I can't say I'm in the same boat as I have a TO box but I am all for this type of thing.

I think the boxes make up for the volume by extending the box back and up to the contours of the tank. This along with removing those big air filters (as you have done) account for much of the increased volume.

Without actually quantifying the lost volume due to the throttle bodies it's hard to determine if there is a difference in the volumes. However I do like the idea of a mod that people can do at home, especially if it gives us even a small bump in power. This can be a great intermediate, and pending testing, a potential replacement mod for those that can't/don't want to afford the aftermarket boxes.
 

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Looks great CBR...damn fine work !!! You may have found yourself a Niche....
 

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Discussion Starter #12
Richard and Hig- I know you guys havent followed my other posts about the air box's but I have an ETI fuel cell and the thorsten/turn one box's wont work with it and the moriwaki/squidskins air box I am not happy with so I took matters into my own hands. Now if someone was good in carbon fiber and wanted to make one of these that would be awesome because they could make it lighter than the moriwaki and almost as light as the thorsten. Like I said everyone goes wooooo to the other air box's but a lot of that extra volume is taken up with the fact that the throttle bodies sit inside the box not with the modified stock!
 

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I'm curious why you do not care for the other aftermarket boxes. I suspect it is that they may not seal up tight and any gained positive pressure is lost. Am I right? If not, share a little wisdom to this new owner. Thanks, Rich
Because he's in the same boat as I am.
We both have an ETI carbon-kevlar fuel tank (mine std capacity, his endurance capacity) and neither are compatible with Turn-One/Durbahn open-top airboxes.

The Moriwaki (and copy) airboxes require thermostat removal, which may not be desirable for street use.

So this is the next attainable modification short of reinstalling the unmodified OEM airbox, or fabricating an airbox that meets all the criteria.
 

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Discussion Starter #14
Looks great CBR...damn fine work !!! You may have found yourself a Niche....
Would be great if I had another bike and only gutted the air box then did dyno comparisons but I dont so I cant....lol but if anyone wants to do this mod its very simple and took less than two hours to do once the air box is off the bike and I did save about 3lbs.
 

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Discussion Starter #15
Hey sub, have you tried flipping the hoses on the thermostat like someone suggested so you can still use it?
 

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Would be great if I had another bike and only gutted the air box then did dyno comparisons but I dont so I cant....lol but if anyone wants to do this mod its very simple and took less than two hours to do once the air box is off the bike and I did save about 3lbs.
would if could brother....but I am in the final stages of purchasing a cf box from a pretty good guy in this forum....:D
 

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Hey sub, have you tried flipping the hoses on the thermostat like someone suggested so you can still use it?
No I haven't tried that.
I was thinking along similar lines as yourself in modding the OEM airbox for the time being.

I didn't want to harm my existing T-O airbox, so I was going to try and locate some aluminum sheet and mesh to fashion a filter system as you did with the T-O airbox parts.

Then the bug bit me on fashioning an airbox that combines elements of the T-O and Moriwaki (large capacity, closed-top, no thermostat removal, etc.).

So I decided to temporarily install the OEM airbox until I get around to making the custom airbox.

Never having worked with FRP or carbon-fiber, I'll see if I can enlist the services of a buddy who does aircraft fabrication and fall on his good graces (in other words, whine pitifully :)).
 

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Discussion Starter #18
LOL on the whine pitifully.... have him make two!! Honestly since I have no way of really testing out the air box im happy with how it turned out. Hack saw blade and a razor blade and a pair of diagonal side cutters (pc) with two hours of labor give or take and I had it in pieces. I did have to plug 4 holes though. Apparently underneath the boltholes for the air filters is straight through, so I put some big screws in there with some RTV on the threads and in the very front of the air box there are 2 holes that I have no idea the function but they worked great to put a small screwdriver in and pry the front part off but now that I cut away all the excess plastic they are open holes so I will more than likely put a bead of rtv in those holes too. I really am surprised how easy it was to modify and how much shit there was in there. I bought the K&N filter and once that arrives (prolly tomorrow) I will fit it up. Right now im in the process of the pair mod and all the other crap from the flapper valve and then doing the soft rev mod and coil pack. Once thats all done i have a night mare of electrical stuff to figure out then I am employing a buddy to help me square away the whole front mount radiator kit. Then its just a matter of putting gas in the tank and hitting the button! I did some dry turn over yesterday (no gas) just to circulate oil through the system, clutch, shift kit, and to ensure everything checks out with no leaks! I wish I was more confident in my electrical skills. If i was I would mod the crap out of the wiring harness and re locate the battery voltage regulator and a few other things.
 

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Discussion Starter #19 (Edited)
comparrison

I can't say I'm in the same boat as I have a TO box but I am all for this type of thing.

I think the boxes make up for the volume by extending the box back and up to the contours of the tank. This along with removing those big air filters (as you have done) account for much of the increased volume.

Without actually quantifying the lost volume due to the throttle bodies it's hard to determine if there is a difference in the volumes. However I do like the idea of a mod that people can do at home, especially if it gives us even a small bump in power. This can be a great intermediate, and pending testing, a potential replacement mod for those that can't/don't want to afford the aftermarket boxes.
If I recall correctly the thorsten/ to box claims 18L, the moriwaki/squidskins claims 15L. I would say the throttle boddies take up 2-3L so from what I read stock RC51 air box is 10.5L so no idea what I gutted but I would say that I should be around 13L and if you take 3L from 18/15 and thats 15/12 and im at 13 im happy! of course all just gesitmates but yeah.
 

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Intriguing indeed...I'm thinking you are relatively close on the math and I think the real deal is swapping the filtration styles. Almost makes me want to carve up my stocker and do a head to head just to see what, if any, differences there are. Very nice.
 
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