Having spent the year helping Riley Graham who rides in the MX2 class, on a KTM 250SX 2T I asked the relevant questions of Kevin Williams at the Coolum round.
Indeed, as stated, no modifications allowed at all to the Cylinder, head, crank, piston, reed assembly. I asked the question about the eligibility of running genuine KTM SXS parts, as they are OEM parts.
The quick answer is no, the parts must be as fitted to the 2015 OEM standard bike- off the showroom floor- and not from the KTM Hard E catalogue.
Mods allowed are intake before carb, carb, ignition, pipe and muffler. Fuel restrictions still apply as per this year. This does not worry me at all for next year, as someone commented, a stock 250 2T is still plenty competitive with a modified 4T, AND AT A QUARTER OF THE PRICE !
We spent bugger all on Rileys race bike this year compared to past years when he raced a 4T, with the cylinder only slightly cleaned up by Kevin Doyle, and a slightly modified head. Kev bored the carb to 39mm, and we ran a Pro Circuit pipe and R304 muffler-not the shorty though. All ran on VP ROO 100 race fuel with impressive results.
It is a boon to privateers like Riley who do it tough moneywise to be able to run a 2 stroke, and the entry list between the MX1 and MX2 classes proves the point. It is embarrassing when the entire field at the premier class of the premier MX championship in Australia (MX1) is struggling to get 25 riders to the gate. The MX2 class however has no such problems.