Hey,
I just picked up a used GS500 that came with a Jardine RT-1 exhaust installed. It also included a K&N lunchbox air filter. WIthout the air filter installed the engine was running rich(checked the spark plugs and they were black). Thought I might be able to solve the issue by installing the lunchbox air filter but now it's running lean(white plugs). Does anyone know where I can find the proper jet settings for that combination? I don't know what settings are in there now as I don't want to pull apart the carb without having the new jets ready to install.
Any help or direction would be great!
The wiki should give you all the info you need on rejetting.
http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting
Did you mean with the stock filter the plugs were black, or with no air filter?
I had black plugs with the stock air filter box.