how to custom fab an airbox with new foam

[BananaMan]

well i am gonna throw in my 2 cents for the discussion on minibike airboxes.

i am sick of the airfilter getting soaked everytime i go through a puddle so i have decided to biuld an airbox. My bike is an Atomik Nitrous 150 MID SIZE.

i have had a good look at the other thread by Dunny29er and his design for a remote aircleaner is good, however with the frame of my bike it just was'nt going to work.

first thing i have done is taken some measurements of my frame and worked out where the air box will sit, i have found that i will need to cut and re-weld one of the braces on the rear frame, no biggie...

to top section of the airbox will be machined from ally and the rest will be custom moulded from fibreglass, the ally top section will have a recess cut around the bottom to allow the fibreglass to mould to and will have 2 removable plates on the inside spaced 22mm apart to allow for the foam, the bottom plate will just sit on a shoulder and the top will be secured using 4 x 4mm button head screws.

i have found that clark rubber sells filter foam very similar to what the uni-filters are made from, if anything a bit more coarse, therefore i am using 2 x 12mm thick pieces so i can get them oiled up properly.

here is a pic of the 2 foams, blue one is a uni-filter, grey is form clark rubber

next i had to start designing the air box top, luckily i have the tools and ability to machine this part up, here is the design i have come up with.

this is a wireframe image of the top section

rendered image of same part

these are views from the top and bottom of the part showing the hex mesh in place to keep the foam from moving
Top

bottom

here you can see the step cut around the bottom with rib to allow for the fibreglass to mould to.


also i have found some marine fuel hose that fits nicely over the carby and have turned up another piece of ally to mould onto the airbox at the other end the same size as the carby.

once i get these parts made i will continue and try and make the box itself, i am looking at using coathanger wire to make a basic frame and stretching lycra over it to get the basic shape (this is how car audio installers get the custom shaped fibreglass boots, once this is set i can then re-inforce with more glass.

will keep updating as the process comes togeather


.

 

[BananaMan]

first update, have machined up the top section of the airbox, cut the hex mesh to size and also cut and fitted the new air cleaner foam

first stage of machining

closer view

here is the top section of the airbox assembled with foam and mesh

view of the bottom, i have rolled the edge to help with airflow and drilled a few 2.5mm holes around the edges to insert wire into for making the base of the frame to fibreglass (2.5mm is the size of coathanger wire)

next step is to modify the rear frame section to allow for the airbox to fit, the bar pictured needs to be moved forward about 20mm, i have removed the frame section but will clamp spacers in between the bolt holes to avoid distortion before welding.

more to come!!!

 

[themountain]

wow....mega bling !!!

 

[roost666]

Nice job man, looks like its coming along nicely, 1 thing tho, where your mounting the air box, wont it cop a lot of dirt and debris being flicked off the tire or do you have something up your sleeve to stop this.

 

[my67xr]

nice work on the machining side of things.
now you will just have to find a nice block of alloy to machine up as a crf/klx frame to match the airbox, lol
pity so much alloy is just chipped away with the milling process, seems such a waste

i can see some custom billet exhaust tips being sold soon too, billet throttles, custom height bar and offset risers, shock extensions, foot pegs, brake pedals/levers
the list is endless

good on ya!

 

[BananaMan]

roost, i am planning on having the bottom of the box sealed and some how having the back edge sealed to the plastics allowing it to breath from the front and sides, thats my plan anyway.....

my67xr, it is a waste of ally but when work leaves offcuts lying around, no point letting them go to waste, (just dont tell anyone they were my offcuts....)

billet everything is possible, if the time and money are right =)

 

[FMX_22]

ahah nice . are you a machinest?

 

[BananaMan]

ok, progress has been a bit slow due to the passing of a family member but i'm back.

FMX, yes i am a toolmaker, specialising in cnc.

well first off frame mods have been done to allow for the fitment of the airbox, front bar got moved forward about 20mm and mounting tabs welded to underside of frame, have not bothered to clean up the welds yet so be nice.

next i took some 1mm ally plate, fixed the outlet to it with some small countersunk screws and fixed the sheet to the airbox top section. then with much frustration and a pair of tinsnips and a hammer and pliers i went about bending it into the right shape and position.
i used 3 m3 screws to hold it in position while i did this, the plan eventually is to get it welded in place and be able to remove the screws.

view from in front

view from behind

these pics show it fitted back in the frame with the pipe attached

from the top

next step is the get all that ally tig welded togeather and then i can go about making the frame and fibreglassing up the rest of the box.

wish me luck!!

 

[wogtaz ryder]

Very nice work mate!

 

[FMX_22]

So so clean did a realy nice job man

 

[tim_]

`looks awesome mate... with the the bar that you moved it you grind the paint away before you welded? n it looks like the weld is sitting on top of the join with not much peno..... the only reason i ask is because with the weight of the rider and wiht the stress of riding it might split the weld where it meets the steel...

 

[FMX_22]

welding will burn through paint . Probs just need the heat turned up a bit

 

[tim_]

yeah it will but it will put impurities in the weld weakening the weld... n i wasnt tying to bag his work out dude just curios is all...

 

[BananaMan]

ok, the weld is good, is was done by a mate of mine who has been a vehicle body maker for 15 years, he knows his stuff, the reason it looks chunky is that the replacement bar is solid so most of the weld needed to be concentrated on that.

secondly, for the first time in my life i was using a TIG welder last night, i thought i had the hang of it and figured 'why not try and weld some of my airbox'

turns out TIG welding is quite tricky....

now i dont know weather to try and salvage the part or just scrap it and start again....

 

[tim_]

yeah makes sense now, you can save it but it will look rough.. up to you really

 

[pitsterproAUS]

very neat job will be good to see the final pics im go smaked at the level ur doing things nice works mate

 

[BananaMan]

very neat job will be good to see the final pics im go smaked at the level ur doing things nice works mate

well i'm really not sure what 'go smaked' is but what the hell, i'll take it as a compliment!!

 

[tim_]

if you do decide to build another one can i give ya some pointers? or have you got a back up plan to get it welded?
i can also help with ideas if you decide to salavage if you like..
agian im not trying to say anything bad or bag out your work just trying to help with some advice...

 

[BananaMan]

sure mate, fire away.

i'm always open to ideas on improving my designs

 

[tim_]

your design is fine mate.. the thing is with alloy it holds more heat for long then say stainless... as soon as you see the weld pool from you need to start moving and use plenty of filler rod so you dont blow a hole through your weld or under cut the weld (under cutting is when the weld its under the level of the alloy)... looking at the pics it seems like on one weld you have gone too hot and other you have gone to cold or re-welded over the top... how do you have the electrode set up in the tig torch? and as for the thinker alloy it looks like you have gone to hot or stayed in one place to long... cause the weld pool seems to be every large.. you want the weld to look like cresecent moons when you have finished...


on the thiner alloy where you have bent it the steel will be thicker so if you start welding from there it will look like its goin ok but when you get to the thinner stuff it will blow out if you dont pick up the pace... the best way to stop the edge of the alloy from blowing out is to tack weld acouple times just next to each other n stop0 the wel on the tack instead of goin all the way to the end.. that way when you add the next side you wont have a hole to fill..