The problem with the KTM TPI is not the fuel injection but the oil injection. It's a crude lash-up of a solution that reminds me of their approach to 2 stroke starter motors.
The USP of the 2 stroke has always been that it is a simple motor principle run on pre-mix oil-in-petrol fuel. Cheap to own and maintain and easy for home mechanics to keep on top of. Its Achilles Heel is that forgetting the oil is fatal.
KTM has then gone and produced the worst of both worlds by making the 2 stroke engine as complex as a 4 stroke whilst leaving the oil injection side prone to all kinds of issues. The initial bikes had oil tanks make of brittle plastic that cracked and dumped the oil as there was no vibration damping for the bolts. Then the rider needs to check the oil feed pipes for air or the pump stops delivering oil and needs bleeding. Or the oil pump just gives up. All this with the rider only realising what's going on when they hear expensive metal on metal noises.
Oh, I nearly forgot.... it has added 30% to the price of a 2 stroke KTM. Result!
The solution may be either to inject premix or for some kind pre-injection buffer where the oil and petrol are mixed immediately prior to injection to allow the oil ratio to be varied to match the engine load and reduce emissions.
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