[paul h]

I have a honda cb550 and my plugs are fouling indicating a rich mixture. I have synched the carbs, adjusted the air/ fuel mixture screw 1 1/2 turns out, put a new ignition coil on, set the dwell and timing, and put a new air filter in. I would move to a hotter plug but plug four looks fine so I'd like to not change plug temperatures. Could my exhaust pipes being clogged lead to fouling plugs? Does anybody have any ideas I might have missed. Thanks!

 

[Rad350Hog]

your carbs could be f'd, or youe fuel lines could be clogged, is your tank full of rust, check it out

 

[Britbiker]

Restritive exhast can cause fouling, but it's minor compaired to all other factors. You have to check everything else before that. A few things to take in account,
Are you using the stock carb settings? remember the fuel mixtures have been radically changed since then
New jets?? (jets wear ov er time, like everything else)
Worn needles?
Worn pilot circurt?
Running the right heat range on the plugs?
My advive, check everything

 

[joe c]

could be as simple as a float adjustment though...

jc

 

[Britbiker]

Yep, gotta check the float heights, on every carb.