I own a 2001 300ex. It starts, it idles, it runs half throttle. When you punch the gas to run it wide open in any gear it starts spitting and spudderin and wants to stall right out. Had the valves adjusted not too long ago, put dry gas in it, had the carb off 2 times and cleaned it.

It runs damn near perfect though when the choke is on wide open.

Need some suggestions please.

 

it sounds like a plugged main jet. did you spray carb cleaner in all the passages in the carb?

 

I agree with quicksilver. Sounds like its not getting enough fuel. I think I've read that off timing has these symptoms too. I'd troubleshoot fuel related possibilities first.

 

Did you remove the lid on the air box?