I removed the oil filler plug and started the bike .

The reason that I removed the FILLER PLUG when the bike was
running is that on dirt bikes all the guys I have ridden with have
always filled the bikes oil pans to the nominal amount when the bikes
are running.  This allows for the motor to have the nominal amount of
reserve oil in the pan when the oil is also pooling in the head, and
transmission.  Since having done this, the oil indicator has not come
on.  I changed the oil this morning, and drained out 3.5 quarts,
excatly  1 quart more than what the manual says would be in the motor. 
So the amount of oil that pools in the trans/head/lines is 1 quart.  So
when I refilled the engine I filled it with 3 quarts.  This will allow
for more oil in the pan then the Yamaha Manual of Truth says ought to be
in the motor, but not enough for the crankshaft to be anywhere close to
the reserve oil.

Louis Tweed