Cylinder 1 slow to kick in

Hello all. I rebuilt my carbs on the xj700 over winter. Cylinder 1 does not fire when the bike is first started, bike runs on 3 and I have to increase the revs to around 3000rpm and cylinder 1 kicks in. Swapped plug leads 1 and 4 and problem still exists on cylinder 1, so it isn't ignition related. Spark plug on cylinder 1 goes black after running, when the others are fine. This indicates that cylinder 1 is running rich, but the mixture screw is now only 3/4 of a turn out from closed and the others are set to 1 and 1/4

 

Welcome to the forum. Them carbs can really be hard to clean. There is a start or choke ckt jet in the bottom of each float bowl.
carbs_floatbowl_choke by Tim Brown, on Flickr
With what you have said, I would take a look at the carbs again and make sure that this jet is clean and that the fuel level is correct.

Cleaning that jet with a thin wire, compressed air and your favorite carb cleaner until it passes liquid through the port. Good luck.

 

And watch your eyes carb cleaner flies out of that once the tube is clear. When I first got my 900f it had starting problems, checked everything I could but did not know about the carb bowl jets. Once I found out and cleared them bike started and ran on all four. Bingo

 

if the above dont work maybe one of the enrichment plungers is stuck open a bit , you can visually check this by looking at all the plunger forks are even

 

Thanks guys, I will do some more work on the carbs and let you know. Much appreciated.

 

Had the same problem and adjusted mixture screw in til it idled good, may have slightly higher float height.

 

Thank you, that makes sense! . I will try and slowly reduce the mixture screw and see what happens. Cheers. Much appreciated. Stu.