Hot running problems

[CB750Skegness]

Hi my 1993 bike RC42 has got a hot running problem
Bike start fine when cold and will run fine for 5 or so miles, then it starts to bog down and lose power, if I pull choke out it seems to let bike run, but only just, but will eventually bog down again and stop. Spark plugs not fouled at all. Bike will start and get me home after a while on choke.
Any ideas what I need to do would be greatly appreciated

 

[MickMick]

Sounds like a false air or slightly blocked jet. The need for the choke is to increase the vacuum through the carb to pull more fuel from the carb Wells. Either the rubber boots from the carbs to the head are leaking or air getting in somewhere it shouldn't. QQ, have the carbs been rebuilt? If so, did the felt seals get reinstalled? Are the jets the correct ones for your filter/exhaust setup?