The Yamaha AT1MX Replica Project
As we already mentioned, At/Ct1's only have
around 3 inches to work with for an air filter set up.
Here is what I came up with. I used stuff I had laying
around my garage and kitchen.
I personally like a foam filter on a race bike. I
wanted to address the long tube for the intake
tract, normally used on AT1 racers,plus I was
starting from sratch, so a clean slate to start. The
large red filter and the cage next to it are for a
CZ.  Here goes, ingredeints Honda sl 125 filter
element, stock, part #17211-107-020  $8  and the
connecting tube #17253-107-782 $18. CZ air
filter cage cut down , Dole pineapple can.  6- 3/16
short rivetts and washers. To start with.
vintagemxracer.com
I found a big  aluminum washer. Actually a
remnant from a hole cutout of 3/16 thickness, it
fit perfect and gave the filter element cage a
good mount. Next I cut some sheet metal I had
laying around, formed it to the frame put a 90
degree bend in it, cut and bent the corners in
on themselves, then pop rivited the folds
together to keep the twisting to a minimum.
The Honda 125 SL connector tube was cut
down about an inch. When finished it's a little
like a miniature Husky filter and flows really
well For a cover all I could find was an Ice
cream container, so cut it to fit. Here is the
finished product.
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