They're not rivets.

They use special bolts which shear when they're torqued up, specifically so thieving types can't just overcome the steering lock by unscrewing the ignition barrel.

So yeah, the only option is drilling them out.

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I spent a lot of money on travel and racing motorcycles - the rest I just squandered.

XT660Z - Commuter, Adventurer...Racer?

www.dashmoto.net

Other bikes >> MT-03 / CG125BR-J / ER-6F
Departed >> ZXR400L3 / EC300 / DR-Z400E / DR800S / GPZ500S / GS400