pic1 Isle of Man - only example I have.
look up the history.
pic2 Manx cat
Grew up with Manx cats, never had a bad one.
Bad pets are usually a sign of bad owners. just sayin'.
Didn't sound as cool tho.
Had a header on my Norton.
2-strokes ring-ring-ring even w/expansion chambers.
Have owned both, 4-strokes have the sound.