Topic: Need a hand with Yamaha XJ550R carb

[Gearhead57]

Working on an 82 Yam XJ550R (seca).
It runs great on the top end, but lower RPM it stumbles and bogs like it's about to die.
Haven't gotten into the carbs just yet, but looking for someone to help me narrow it down, or confirm my theory.

The way it bogs at low rpm but then comes alive HARD at mid to upper RPM I get the feeling that it's trying to say either the pilot jet or needle are too rich.
The girl it belongs to says she never needs the choke to start it, and the time I rode it the bog wasn't as obvious right after starting it up, got worse as it warmed up.  (continuing to lead me to believe it's rich at bottom)

Anyone care to enlighten me or agree with me?

[HavocTurbo]

I would tend to agree but first things first.

Pull the plugs and check color.

XJ's are notorious for leaking intake boots. Every single one I have seen has leaky ones. So after you get it fired up and warmed up  take a can of carb and choke cleaner and spray each intake boot individually.

If that changes the idle in any way that sucker is leaking. Be sure to check all of them top and bottom.

After that either ask your dealer or find the stock settings for the carbs and try to bring them back into spec. Then synch.

Would seem to me that a serious cleaning would help as a starting point for diagnosis. That way we aren't hurting our craniums agianst the wall.

[Gearhead57]

Needles were super gummy, cleaned them up and threw some carb clean in the bowls.
i cant see an easy way to get the carbs off.
Is there a trick to this?    I'm searching for a service manual

Going to put in new plugs (black) and an oil change. Might be enough to help it out.

[HavocTurbo]

I cannot remember but remove the seat and unbolt the air box.

Should be a couple of bolts on top somewhere. Might be under the tank.

Then loosen clamps on both sides of the carbs and fight and swear till they are out.

The float valves are press fit so don't remove them unless you have replacement 0-rings.

That's all I got at the moment. I'll look for a manual when I get home.

[tonycb650]

air filter?