To continue the discussion on a slight tangent has anyone used oil additives?

I purchased my FJR in March this year and I believe I would rate it as one of my best purchases, the only thing I don't like is the clunkey gear box and engine whine.

My son the Auto Mechanic suggested using "Lucus Heavey Duty Oil Stabilizer". The label states it can reduce gearbox and engine noise and it is recommended for motorcycles.

Has anyone used this in their FJR or recommend an alternative? Thanks.