Domni exhaust ports

[jseng1]

Are all Dominator ex ports the same size and shape as the Commando?

 

[Matchless]

If you mean the thread, then yes. The angle the port exits the head is different for earlier heads though.

 

[jseng1]

If you mean the thread, then yes. The angle the port exits the head is different for earlier heads though.

Not the threads but the port shape. Do you know when (what model domni) the port angle changed? I'm wondering if the raised D exhaust floor with fit any Domnis?

 

[hybridracer]

The exhaust ports are all the same shape in the 650 that had the ss head, 88ss(with the 650ss head), atlas, 750 & 850 commandos. In other words, all production models that used heads based on the 650ss head.

 

[norton bob]

The Downdraught SS type head with the wider splayed exhausts became publically availiable first on the 650 Manxman and then the 650 /500 SS bikes in the early 1960 's probably 1961 ? , Its first use perhaps on a factory Dommyracer?

 

[kernel65]

DynoDave’s research on Norton heads here:

norton heavy twins heads