Help with a type of chain ( its proper name )

[Jaws]

Got a total brain block

The chain in question is the multi width type as pictures
I THINK the name is something that begins with 'vari' but I am buggered if I can remember.. been struggling with it on and off for weeks !

Not a great picture but..........

 

[Jaws]

better picture

 

[Malone]

Hyvo

look here for examples, I think Z1 Kawackers use them

HYVO Chain, 3/4″ Wide – Wahl Bros Racing

wahlracing.com

 

[ChildoftheJago]

Silent chain (inverted tooth or Duplex) isn't it?

 

[jerryt]

Hyvo I think the CBX1000 uses one! I believe as they wear they grip the sprockets better!

 

[Squag1]

Chain Drives & Types of Chains | Fractory

Chain drive is a type of mechanical power transmission system that uses chains to transfer power from one place to another.

fractory.com

 

[jerryt]

If you google 'HY-VO' you find it is the trade name of Borg Warner who make them!

 

[Jaws]

The word I was looking for is indeed Hyvo

Thanks guys....