Hello, posting this question for my son who is doing a cb750 k2 cafe racer. First let me say that he has just got his bike back from a honda dealer who re jetted the carbs and tuned the bike. It starts and runs fine but on the road it will not advance above about 4000 rpm. He had installed a new 4 into 2 into 1 exhaust and put pods on it for the intake and then took it to a honda dealer for the carb work. They did not have a dyno and just rode it around the parking lot and it ran fine. He got it home and took it out on the road and thats when he found it dead above 4000 rpm. Any suggestions on what the problem is? any help will be appreciated. thanks.