For 1-1/2" carb applications (HS4, HIF4/38,) this Conical K&N filter is the answer. Fits single or dual carb setups. Sold individually.
K & N airfilters are unsurpassed in performance yet are compact in size to fit in even the most cramped quarters.

56-9320 Product Specifications
Weight: 1.1 lb (0.5 kg)
Product Box Length: 6.56 in (167 mm)
Product Box Width: 6.31 in (160 mm)
Product Box Height: 3.5 in (89 mm)

K&N developed and manufactures the only air filtration system of it's kind..a high flow, washable filter that's been proven to be the finest in the world. Professional racers and mechanics worldwide rely on K&N air filters to protect their engines..and so should you.
The cotton Gauze filter design from K&N provides the positive gains that you would expect. Average filter life is 100,000 miles! Highly polished chrome cover pancake air filter. Round 5.875" diameter x 1.75" high with center hole for 1.75" SU.

Highly polished chrome cover pancake filter. The cotton gauze filter design from K&N provides positve gains that you would expect. Average filter life is 100,000 miles! Oval 4.5" x 7" x 1.75" high to fit 1.75" SU. K&N developed and manufactures the only air filtration system of it's kind..a high flow, washable filter that's been proven to be the finest in the world. Professional racers and mechanics worldwide rely on K&N air filters to protect their engines..and so should you.

Highly polished chrome cover cone filter.
The cotton gauze filter design from K&N provides positive gain that you would expect. Average filter life is 100,000 miles!
'Conical' 5.875" diameter x 2" high, fits 1.75" SU carb.
K&N developed and manufactures the only air filtration system of its kind: a high flow, washable filter that's proven to be the finest in the world. Professional racers and mechanics worldwide rely on K&N air filters to protect their engines – and so should you.
NOTE: not compatable with the SS53 stub stacks.

K&N for Cooper S
Sold each. Two required for twin carbs.
K&N are arguably the best air filters made, and luckily enough the are available specifically to fit left hand drive HS2 (1-1/4") twin-carb Minis like the Cooper S! You will see Minis with other brands of filters where the filters actually hit either the master cylinders or the fire wall! Nothing out performs the K&N, and because they're washable, nothing outlasts them!Sold each .

Highly polished chrome cover pancake air filter. Round 5.875" diameter x 1.75" high with offset hole for 1.5" SU. The cotton Gauze filter design from K&N provides positive gains that you would expect. Average filter life is 100,000 miles! K&N developed and manufactures the only air filtration system of it's kind..a high flow, washable filter that's been proven to be the finest in the world. Professional racers and mechanics worldwide rely on K&N air filters to protect their engines..and so should you.