Brad The Bike Boy: Airbox / Air inlet mods for Sport Classic and Hyper Motard 2V

Saturday, July 4, 2026

Airbox / Air inlet mods for Sport Classic and Hyper Motard 2V

Fixing the Sport Classic and HM airbox restriction the cheap way.

{{digressing}} The expensive way is the StarAce airbox. A customer brought one in a couple of years ago for me to fit to an SC1000, and with the ECU file (well, numbers dumped from a twin shock based file into a single shock file due to the different air temp sensors) I had made up for another bike running the big flat MWR panel airfilter (ever tried washing one of them?), based on one of Tom's Zard with hacked airbox maps, it was surprisingly fast. Equal to anything else I've sampled on one of these bikes for sure. Like "get it into second before you open it all the way or you'll be over" fast. Bringing the wow and yeah baby, and the typical issues pertaining to those lacking resistance to temptation and restraint.

{{getting back to the subject}} The little square hole on the right is all the air entry these bikes have from the factory - it's amazing they can make any power at all, left alone 85 ish.

The big hole at the top and smaller hole through the bottom are the low buck improvements. Love the hole saw. The big hole at the top is the Ducati Performance-esque easy bolt on improvement. The hole in the bottom the "well, we're here, so why not" improvement. Just don't hole saw to far through and into the shit below - it's much more useful in its original condition.

This one had two seized screws and spinning inserts too - the two closest to the filter front and left. While the little 8mm screw heads meant I could very conveniently hold the head while drilling the head off, one wound out happily with the LH drill bit, while the other thread at the front was seized into the insert. With the heat generated the plastic surrounding the insert when soft and it came out the bottom of the airbox moulding. I drilled through the rest of the M5 thread to get it from both ends and gave it the Wurth Boltex treatment. With the insert held securely in the vice, one of the old style (and generally crap) reverse twist easi-outs just wound it out. Happy days! Smothered in araldite and jammed back into the airbox, the insert seemed to hold just fine with a screw back in it. Just don't go too tight.

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