Topic: Newbie first cb750 bike

[chanhcao]

Hey guys I just bought myself a 1981 cb750, when i bought it we tried to start it but the battery was dead and the owner said he hasn't drove it for over a year. Bought it for a cheap price so i didn't worry so much about the problems. He said bike would turn over and run but he didn't tell me that he won't go over 45mph. I have opened up the carbs already and have clean it out, replaced gasket and also the peacock. Changed the oil, filter, air filter and spark plugs. What i noticed that when i did changed the spark plug it started running really rich. Do you guys have any ideas what might be the cause of the reason why the bike wont go over 45mph?

[birdmannn101]

Looks like it has a regular airbox on it, can't tell from the picture.  I know I had the same problem with mine but it had pod filters on it and standard fuel jets.  When I went back to the standard airbox it came alive.

[chanhcao]

it is the standard air box, i did want to do pods bc its so much easier to install and replace but i heard it change the bike completely so i steered away from it. any suggestion on why this is happening?

[birdmannn101]

Pods are okay but you have to change the jets or you loose power because of the change in amount of air coming into the carbs.  You definitely have a fuel/air mixture problem.  If you already cleaned the jets when you cleaned the carbs I would start it up and re-adjust the air/fuel screw to run the best at low and high RPM.

[chanhcao]

well the problem is now when i tried fixing the problem i now can't turn my bike back on. it will crank but won't start. any suggestion?

[birdmannn101]

What did you do to the bike when you said

well the problem is now when i tried fixing the problem i now can't turn my bike back on.

[chanhcao]

i opened up the carbs again and checked if the springs were okay, everything looked fine then closed by up it wouldn't turn.