Carb running rich or lean?

woozybigfoot

CB750 Enthusiast
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So I recently purchased an 82' cb750 f super sport. Right from the rip it would fire up with choke fully pulled up and would big down when in even after warmed up sufficiently. I changed the coil packs and spark plugs and bottomed out the carb adjustment knobs and back them out 2 turns. With those changes I had about the same issue but know it would fire up consistently and all 4 cylinders sounded to be firing fairly equally. They were not before hand. Two cylinders were running significantly colder. Now they were firing consistently and heating up evenly. Once warmed up I adjusted the idle adjustment to have the bike be able to idle fine with the choke pushed it. She likes being at about 1200rpm idle. This brings me to my newest quandary. How can I effectively tell if any of the cylinders are running rich or lean so I know how to adjust them accordingly. What is the tried and true method for checking an gauging wether each cylinder is running lean or rich. Do I just take the spark plugs out and eye ball them until they are seeming to be running evenly and have a good color to the plugs... Or is there a method of hitting the throttle and listening to how it goes back down to idle to gauge wether it's running rich or lean.

Thank you very much for the info I am a newbie to the motorcycle and carb game but very eager to learn more about these awesome bikes
 

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Plugs are the best way to tell if they are running lean. If your rev the bike and it doesn't return to idle quickly, meaning it hangs, you have a vacuum issue, with a couple possible causes.
 
Plugs are the best way to tell if they are running lean. If your rev the bike and it doesn't return to idle quickly, meaning it hangs, you have a vacuum issue, with a couple possible causes.
Okay go on what could the causes of the vacuum leak be? Because it doesn't really seem to hang but it doesn't really want to "snap" if I throttle it quick.... If that makes sense
 
Then you don't have a vacuum problem. If the bike doesn't like to take off quickly from idle, it is likely a dirty accelerator pump or a needle that isn't lifting when you roll on the throttle.
 
Then you don't have a vacuum problem. If the bike doesn't like to take off quickly from idle, it is likely a dirty accelerator pump or a needle that isn't lifting when you roll on the throttle.
Okay sweet so then those are my next two culprits I'll be investigating on thank you! Getting to know these bikes is really fun it's a fun ride as well
 
If you want to learn from experienced guys, you can watch some YouTube videos on these carbs. Look for brick house builds or classic octane (doesn't post much anymore). There are others I'm sure. Some of those guys will give you how carbs work in general and are a great resource
 
If you want to learn from experienced guys, you can watch some YouTube videos on these carbs. Look for brick house builds or classic octane (doesn't post much anymore). There are others I'm sure. Some of those guys will give you how carbs work in general and are a great resource
Okay absolutely will look them up I've been watching a lot of motorcycleMD on youtube that guys seems very knowledgeable as well
 
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