XJ550 fuel/air ratio

Ok I am going to fix my bike by addressing the problems seperatly. It doesn't like to idle unless its on full choke and it still barly chugs along. Last time it was idling like that I sprayed some starter fluid (ether?) through the air intake and it died. This makes me think that there its not enough air getting in. I don't have an air filter yet. I have cleaned out the carbs somewhat. Are there some adjustments I need to make on the carbs? Could they be so out of tune that the engine doesn't want to run?

 

pull the carbs, really clean bench sync them, and set the mixture screws to between 2.5 and 3 turns out. Then you'll at least have a starting point to begin trouble shooting. If your carbs are too far out of sync, it'll have a hard time idling... if the mixture is too lean or too rich, you'll have the same problem.

some stuff you can do without ripping into the carbs....

check for spark at each cylinder

pull your fuel line and make sure the petcock is operating correctly. It should drain unrestricted on prime; if its set to on or res, vacuum needs to be applied to the vacuum line (usually plugged into the #2 manifold vacuum nipple). You can check it by sucking the end of the line (theres cleaner ways, but sucking is fast....) fuel should flow only when there is vacuum present...)

If you have fuel flowing freely into the gas line, set it to prime, and unscrew the carb drain screws, located at the bottom of the carbs. When you unscrew (it might be tough to get the screws out....) fuel should flow out the drain port.)

visually inspect the intake manifolds... make sure the vacuum ports have the caps on.

For the engine to run, you need air, fuel, spark, and compression.

You have air, (you might have too much until you restrict the air passage with the filter...the mixture is touchy, and it won't be too happy without the air filter.)

If you check and have spark, fuel and compression, and still no run, then something is too out of adjustment for it to hold idle.

At that point, pull the carbs and go through them again. Once your positive that its absolutely clean, bench synced correctly, and you have the mixture screws in the ball park, reinstall and you should at least be able to get an idle.

Then you can sync at idle, and fine tune your mixture, and roll...

 

idling with the enrichment circuit on and not without it is indicative of a clogged fuel jet. Pull the carbs, remove the bowl and the jets. Then blast them free and clear with carb cleaner. also blast the passageways inside the carbs to ensure they are clean. Pop out the emulsion tubes as well and make sure all the atomization holes are clear. This should take care of this problem. Don't forget to check your float levels before you fire it up again.

 

I bought a carb rebuild kit. Are there some good tutorials for how to get at the fuel jet/ check float level around here? thanks, nik

 

shove clear tubing into the drain hole, and loosen the drain screw. hold the tube up the the carb body, and it will show the level.

you can search for float level, and theres tons of posts... the level should be a touch below the gasket surface if i remember correctly.

 

You need to make sure no air is trapped in your clear hose or the carb drain passage, this will mess up your level big time.

You should really check the level at the side of the carb. To get there the hose wants to go down from the drain and back up. I start with the hose running up until it has fuel in it, then move it to the side for the reading.

Don't use a hose that is much longer than the length required. Low spots can trap fuel and keep the level from being accurate.

Anyone care to guess who has had to redo float levels because he had a long hose with puddles of fuel in it?