[hagrid]

Just based on the few details you provided it sounds like a hydraulic lifter isn't pumping up completely; hence the kerosene trick.

Ask your friend for the repair invoice on his bike: I bet the lifters were replaced.

I would search kawa v-twin forums for specific info on your model year.

 

[hagrid]

40 grade is 40 grade: it matters not whether the base is conventional or >/= PAO 3 base.

What you'll find is the synthetics flow better when cold (lower W number) and need less additive to maintain their service life.