Oil is likely a rubber plug under the head cover... $15 DIY fix, (see Tech section)..
Do this test for your running problem, oil in air filter problem... very common. Easy DIY fix too...
Test your Petcock,.. don't just turn it to Prime.. $1800 for a 5k 99',.. ain't a steal, but it ain't awful either... Test the petcock first... see what happens.
as for rectifier...,... not sure... Do you trust the guy that tested it?...
Rectifier failure is rare on this bike...

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