What Is This Pitwork Part?

[8110]

I have the below part (ER34) but am unsure what it is. Anyone have have an idea?

Pitwork Part No. AY460-NS010 (In Jap it's said to be a テンショナー)

Where does this go on the engine?

I have have another Pitwork Part, which supposedly is a idler pulley (アイドラプーリー), Part No. AY660-NS001

Where does this go on the engine?

[8110]

Could the first one be a Tensioner Pulley?

[Lazy-Bastard]

Could the first one be a Tensioner Pulley?

That would be my guess

[Lazy-Bastard]

Where does this go on the engine?

Tensions the timing belt