1981 kz550 keeps shutting off

i bought a 1981 kz550 from a guy on craigslist and it ran fine for a while after buying it but now it will randomly shut off while im driving. It doesnt matter what speed im going it will still shut off and it does it at different times, for example i went on a ride and a couple miles in it died but a week later i drove 62 miles with no problem then a few days later it did it again. It jerks and looses throttle and then cuts off and sometimes it takes a little while to start again and sometimes it takes a minute or two. I talked to one guy who works on them and he said it could be the pick up coils or the ignitor

Hello and welcome jsaleen

For me it sounds like your fuel line or fuel tap filter mash is clogged.
The vent in your tank cap can also be blocked and produced a vacuum that stops the fuel flow.
These are the reasons that you looses throttle ( lean air / fuel mix condition ).
Some pictures of your spark plugs are a great help for us.
A broken coil or pick up will shut off the engine immediately.



Michael

scirocco, here are the spark plugs they are in order as they would be on the bike going from outside left to outside right. I dont know if it means anything but when i pulled on out smoke came out too but just for one. And also i am hearing a little knocking noise too.

Make sure your fuel line does not have a tiny kink in it from the tank to the carbs. I was having a similar issue last year with my 550. Realized the new fuel line I made was just a tiny bit too long and once the tank was in place it would close up. If I was running the bike at cruising speed it would run the line dry.

In my opinion your spark plugs are looking a little lean

Reference chart



Michael