I changed my spark plugs this weekend, then started her back up but once fired up the idle speed was a lil rough from 1300-1100 (aprox) then back to 1300-1100 and so on and so on. Not extremly hardcore just a constant up and down of RPM. Then my step-dad comes over and places his hand in the exhaust and tells me that the mixture smells a lil stronger that it should. Then takes a shop towel and forces it over the exhaust pipe, and it was then that he showed me how the exhaust seam to have a "back suction". He told me that it could be a falty valve that is not closing properly, however, he wants to use his experince to tune up that air/fuel mixture first. My question is: "has anyone ever done this on a carburator F4?" becuase once reading my service manual apparently the "PILOT SCREWS" are located on the bottom rear part of the carbs making it nearly impossible to reach. So if anyone has ever done this on their bike can you explain how u accomplish this? Thanks to all pic below "pilot screws are marked with green arrow

 

when you changed the plugs, you should be synching the carbs too.

 

yeah I was getting that feeling after running searches all day long. . . should I clean my carbs while Im at it and synch afterwards??