Look what we made.

[marz831]

The 750 manifold seems to be more of the size of the ATP manifold. I'm not sure what the runners look like on an ATP though.

 

[Vumad]

I find uit unlikely that Riva would sell the manifold for the 44-46-mm carb if it was not capible of allowing proper air flow. I could understand if it was a 650 manifold and a conversion plate for if you have the manifold already, but they sell them together. If it dind't work, they'd be forcing you to buy the right manifold. I think you're safe.

Making a billet manifold would be insane. Go with a Kawi/yamaha conversion.

Personally, I think the manifold isn't restricting airflow. As long as the inside is the same as the throat, when it should work, no?