XJ550 No Idle

Hey everyone. I've been working on an 82 XJ550 seca over the winter. Today I just got it started. Started right up with the choke but idled up to 4000. Killed the choke and it dropped less than 1000 and gradually died. So I adjusted the idle speed screw and tried again with same result. The idle screw seems to do nothing. It will only run if I constantly adjust the choke, even then it's irradic. Will be fine in one spot then high rev, I'll adjust choke to where it's fine then it will start to rev again. The throttle is sluggish as well. I think its running lean.

I cleaned the carbs, new jets and float needle. Set the levels and those were good. I didnt change throttle shaft seals, I forgot all about them actually. If I could at least get it to idle I could spray them with carb cleaner and check for leaks. Could a slow fuel supply from the tank cause lean symptoms or irradic throttle? I have an inline filter on, it's a tight fit and my line is a little kinked.

Any help or comments is appreciated. If you have any questions feel free to ask.

 

I'd suspect a vacuum leak, assuming other stuff is in order. If you could get it to idle at a reasonable speed without racing, blow some propane around to see where it gets sucked in (and raises the RPM).

EDIT: should have read more than your first paragraph... throttle shaft seals can easily be a leak source. If they're original (or quite old), I'd go back and do those.

 

You answered your own question.

Also,
Idling on choke, but not on the pilots usually means that the pilot circuits are still clogged.
Did you remove the air jets? Did you put them back where they came from (not where the manual shows)?

 

All jets were removed, main and idle jet are new, the air jets are clear. I was able to blow air through all the passages well, so they should be fine. After I put the carbs back on the bike I thought about shaft seals. I'm going to try and check them for leaks, but probably replace them anyway.

I did set my idle mixture screws at 2.5 turns out. Is that a good starting point based on everyone's experiences? Just trying to work through everything.

 

did you bench sync the carbs?
when you use the enrichment circuit/Choke the bike starts and as it warms up the rpms will climb to 4k rpm normal.
use a longer fuel line get the kink out run it to the carb behind the bracket not where the clip is.
how long do you warm it up on the choke?
did you set the fuel levels wet set?

 

while you're messing with the carbs, put a small charger on the battery or your next post will be about a dead battery.
if you have a 2 bottle sync setup you MIGHT be able to get it going without pulling the carbs again

 

Thanks for the help guys. I just pulled the outermost shaft seals and they basically fell off the shaft. So definitely need replacing. Stupid of me, I know. Next payday I'll get those ordered and installed. Then bench sync again and I'll set float levels again, just to be extra sure they're good. Reinstall the rack and reroute the fuel line to work out that kink. Hopefully that sets her right, if not, I will definitely be back.