Hi and welcome to JustAnswer,
Thank you for the question and your patience. Should you still need assistance for information purposes only...
Initially, bear with us; re-confirm and post back with the complete model number of the "...2003 90..."
Still, most oil injection to the carb are fixed and governed only by the amount of suction/vacuum.
A common / known cause for "...lot of smoke in the exhaust both idling and when riding..." would be oil sludge and carbon deposit inside the exhaust system itself.
In certain instances, it would be carbon deposits at the cylinder head, piston and exhaust port of the cylinder or worst, a poor compression / loose rings.
In others, pre-mixing the 2-T oil in the fuel tank to a leaner mixture say 1:40 would reduce smoke emission.
Additionally, electric choke operates depending on the temperature. If cold, the richer the air/fuel mix. Normal or hot, then it has no 'play'.