Carburator Problem ?

[badgertom]

Since I purchased the 1980 xs400gs a couple of years ago I noticed carbon fouling ( rich mixture) on both spark plugs. I checked and cleaned the air-filters, checked idle, used hotter spark plugs, etc. Nothing seems to change the condition of the plugs. ( I should add that I replaced the mufflers with JCWHITNEY Megaphone mufflers, which I believed to be similar to the original mufflers). In anycase, should I replace the main
jet (#135 with a smaller #132 jet) to see if this works? Also, there actually are two "main" jets. The other is # 160, ahould that also be replaced? I'm not a mechanic but I like to tinker, esp. during the cold Wisconsin winters. Any thoughts or suggestions ?

 

[DCopp]

what carbs have two main jets? Not BS34's. obviously its getting to much fuel from the main. a 135 to a 132 is a small change. I'd try 122's or so and buy a pin vise drill bit set and make it bigger as needed.

 

[drewpy]

try screwing in the pilot 1 turn in.

check for blocked air jets

 

[gentlemanjim]

If he has free flowing exhaust, i wouldn't go leaner than 132.5 stock. Regardless of your observation of sooty plugs how is it running through the full rev range?