Topic: Pulled Carbs out of CB650 and noticed something funny

[1979CB650_Chris]

Hey everyone,

I just pulled the carbs off of my recently purchased CB650 and noticed that a jet was screwed way out.  The other three looked like they were around the same area but the jet on the number 2 carb was noticably different.  Anyone out there know why someone would turn it way out?  According to the guy I bought it from he had the carbs tuned and it ran decent before he let it sit for 2 years, but I'm starting to think he is pulling my leg.  I hope not since he is a pastor lol. 

Thanks,
Chris

[SteveD CB500F]

Do you mean the air screws?

[SteveD CB500F]

Before you do anything else, go to the Carb FAQs and read all about carb cleaning, synching and air screw adjustment.

If the PO (pastor or not) had to adjust them that differently to make it idle, then there's probably something else wrong.

[SteveD CB500F]

Do you have PD51s?

[scott_cb650]

Notice in the link you reference that your cabureter type is mis-labeled as 1 but when you go to the descriptions of the type, it fits a "2" which implies an accelerator pump may exist.
o Partly Accessible Emulsion Type Idle Mixture Screw
o Non-Replaceable Slow Speed Jet, Some Models
o Non-Adjustable Jet Needle, Some Models
o Accelerator Pump, Some Models

[DammitDan]

Yeah it's gotta be the idle mixture screw.  Are they on the front underneath side of each carb, with a little flange to keep it from turning too much?

If so, then maybe the PO just didn't know what he was doing...  Trying to fix a gummed up #2 carb by adjusting the first thing he saw?  Who knows.  When I got my bike, the PO had turned every idle screw to drastically different settings.  Who knows why people do the things they do?

Check out cb650.net for some great resources.  Log into the forum and go to the carburetor section...  Stickied to the top is a complete manual rundown of your carbs.