A new member wanting to say hi to every one

[Water Warrior 2]

If my memory still works I think I have a little info on the twin dome thing. Back in the late 70s/early 80s Suzuki was dabbling in four valve heads on their performance bikes. The technology naturally filtered down to the GZ engines and their stablemates. The twin dome heads were supposed to have a swirling effect for better mixture control of fuel and air. 2 smaller valves are lighter and flow more air than one larger valve with it's greater weight that is a limiting factor for high RPM. Modern FI in the TU 250 probably lends itself well to lower production costs with a 2 valve head and a single exhaust header pipe.
Modern FI 4 valve per cylinder performance engines have awesome power curves using shim and bucket valve adjusters. A 600 sport bike can make almost 2 times the power of my Vstrom and rev as high as an F1 race car.
In the 60s Honda had a 6 cylinder 250 for the track that was unbeatable. Tiny little low weight parts allowed it to rev to unheard of RPM at the time.

[alantf]

Originally Posted by lenkf

Thus, the GZ250 is no longer manufactured, at least not coming to the US now.

I think it's more to do with emissions. America seems not to like anything that has a carb. They want everything to be FI. There are plenty of 2012 bikes on the web that state "not in North America" as they're fitted with carbs. Every other country in the world seems happy with them.

America seems obsessed with "emissions". Our island's got one of the world's highest number of vehicles per area, including a lot of old leaded fuel vehicles, and according to the sensors installed in all the major towns, the air is relatively clean. So - Who's kidding who in America?