TimG
XS650 Enthusiast
So here is what we have. 1975 XS with BS38's from 1975 as well. I have owned the bike for 2 years.
The bike idles and runs well. It pulls clean through the gears and RPM range.
The bike is stock with the exception of pod filters and aftermarket pipes. They are the EMGO Commando from Mikes. Floats are set at 24.5mm from the top of gasket to the top of float. I have checked cam chain tension, valve lash, timing chain tension and timing "in that order". I just finished cleaning the carbs and pulling the main jet, pilot jet and needle jet. They are shown in the attached picture. The needle is set to 1 and the pilot is a 45. The main does not have any markings on it. I bench sync'd the carbs before adding a pair of carb boots with vacuum ports on them and reinstalling. The carbs were then synced using vacuum gauges. The air fuel is all the way in (full lean).
My air fuel mix screw does not want to backed off at all. the fastest idle I can achieve is definitely all the way in. I have also always thought the bike ran a little rich. Plugs definitely show as such. I guess I need to change the main jet, because right now I have no idea what size it is. I was thinking about starting with the 127.5. and leaving the needle were it's at. Running it and seeing if there were flat spots and then raising the needle to 2+ until things improved.
Any advice would be greatly appreciated. Thanks.
The bike idles and runs well. It pulls clean through the gears and RPM range.
The bike is stock with the exception of pod filters and aftermarket pipes. They are the EMGO Commando from Mikes. Floats are set at 24.5mm from the top of gasket to the top of float. I have checked cam chain tension, valve lash, timing chain tension and timing "in that order". I just finished cleaning the carbs and pulling the main jet, pilot jet and needle jet. They are shown in the attached picture. The needle is set to 1 and the pilot is a 45. The main does not have any markings on it. I bench sync'd the carbs before adding a pair of carb boots with vacuum ports on them and reinstalling. The carbs were then synced using vacuum gauges. The air fuel is all the way in (full lean).
My air fuel mix screw does not want to backed off at all. the fastest idle I can achieve is definitely all the way in. I have also always thought the bike ran a little rich. Plugs definitely show as such. I guess I need to change the main jet, because right now I have no idea what size it is. I was thinking about starting with the 127.5. and leaving the needle were it's at. Running it and seeing if there were flat spots and then raising the needle to 2+ until things improved.
Any advice would be greatly appreciated. Thanks.