Yamaha MT-07

[Constant Mesh]

Look at the exhaust cam sprocket. What is the mechanism? It doesn't appear to be a standard chain sprocket.

https://www.motorcycledaily.com/wp-content/uploads/2013/11/YamMid1-5.jpg

https://www.motorcycledaily.com/2013/11/yamaha-introduces-mt-07-lightweight-affordable-689cc-twin/

 

[ionbeam]

Look at the exhaust cam sprocket. What is the mechanism?...

• This is what happens when an engineer isn't closely supervised.
• The draftsman that made the exhaust cam drawing really confused the machine shop.
• The CAD/CAM software had a serious glitch.
• The Yamaha engineers obviously forgot to tell marketing about clever features they designed in.
• Compression release for the kick start.
• Variable valve timing/cam phasing.

Look at that manly spring on the CCT!

 

[Geezer]

I suspect VVT. I've never looked closely at it but it is pretty common on small car engines.

 

[Constant Mesh]

VVT is often used on intake cams only and sometimes on both intake and exhaust cams on high performance engines.

I've not seen it used on just exhaust cams.

Those balacing shaft weights are huge. Make's one appreciate just how tiny the ones are on the FJR.