I've got a 1983 Honda nighthawk 650. I've just rebuilt the carbs on it. They were cleaned via ultrasonics. They were properly reassembled and synchronized. The bike cranks and idles mint. Rides well to but at half throttle the engine bogs and will not get past the bog, if held it will only die.

I've taken into account fuel starvation but the floats are unable to be set.
All filters flow freely plugs all seem fine. All filters are new.

Possibly carbon plugged exhaust? Bad timing? I'm at a loss.
Any information that could help me resolve this issue would be most appreciated.

This was an existing problem on the bike. A set of carbs were purchased off a running bike and still the same issue. Seems like it isn't getting enough gas at high rpm's...

First thing that comes to mind is the air gas mixture adjustment, or a choke valve stuck open. Does it get better once it is hot?

Sounds like it might have vapor lock.Check to see if your tank vent is blocked.

OK. I'll bite. Just had the same thing happen on a leaf blower. New plug. New filter. Cleaned carb (not taken apart) and idles beatifullly. Give it gas and it wants and does die. Loosened cap. Same thing.

Sound familiar?

Water in the gas. Added seafoam to gas. I had to run it for a bit before it settled down and behaved.

So see if it happens with a loose gas cap. Add seafoam.

W