XJ550 maxim:Wont stay running. Help?

My 1982 Yamaha XJ550 won't stay started, it will turn on and run for about 2 seconds and then just can't seem to idle so it shuts off. Any thoughts on what I should do?

 

Have you done any work on the bike? How long have you had it and did it run good before?
Carb problems is what comes to mind first. But it could be a number of things.
Check those valve clearences.
Clean the fuel system, tank and carbs.

 

Do you REALLY honestly want to know?

Here you go. Items in bold will be CRITICAL to getting it running right.

The best place to start is to get a set of manuals. I say "set" because the aftermarket book (Clymer for the 550s) has a lot of gaps that are covered by the factory book, but the factory book is sparse on details that are covered by the Clymer.

While you're waiting for the manuals to arrive, read the first six or so linked articles in here under "Cool Hand Luke:" http://xjbikes.com/Forums/viewtopic/t=27544.html

Best practice is to go through the "maintenance" section in the manual, procedure by procedure, skipping none and leaving nothing out. Along the way you will discover what needs to be cleaned, renewed, refurbished or outright replaced. If you DO ALL of it, the bike can and will be quite reliable afterward. My '83 550 has rolled 8500+ miles on the odo since I put it back on the road, with nothing more than regular oil changes, a new rear tire and a couple of chain adjustments.

Here's a basic list:

- check tires, condition, and date codes.

- inspect wheel rims for damage or excessive runout.

- check front brake pads.

- inspect disc brake calipers for damage, wear (thickness), or excessive warpage/runout.

- VISUALLY check rear brake shoes for wear/delamination; adjust rear brake pedal linkage. This is very important. Delamination is common, the only way to detect it is to SEE it. http://xjbikes.com/Forums/viewtopic/t=15874.html

- inspect/lube/adjust/replace final drive chain and sprockets. Keep an eye on the chain. If it "bleeds red" when being lubed and won't hold adjustment, it's rusted internally and will need to be replaced. Always replace both sprockets with a chain.

- check and adjust if needed operation of front and rear brake light switches.

- replace rubber brake hoses (check the mfg date stamped in them).

- unless known to be otherwise, plan on rebuilding the brake master cylinder and caliper(s).

- check and clean/replace the air filter element.

- change all fluids: fork oil, engine oil, and brake fluid. Be sure to use MOTORCYCLE oil, not automotive oil.

- smell old oil for signs of fuel contamination; this will indicate a need for immediate carb (float) attention.

- check and repair any engine or drivetrain/suspension fluid leaks.

NOTE: almost any original oil seal or engine case gasket will need to be replaced when its cover is removed for the first time.

- check and adjust/lubricate/replace steering head bearings.

- check and adjust/lubricate/control cables and speedometer and tachometer (if applicable) drive cables..

- check and adjust/replace rear shock absorbers.

- electrical system inspection, replace fusebox and most probably alternator brushes.

- check battery condition; replenish fluid (distilled water only!).

- clean the battery terminals.

- check all lights for proper operation and brightness (headlight, tail/brake light, turn signals, dash illumination).

- check horns for proper operation and loudness.

- check stator resistance.

- check rotor resistance.

- check battery.

- check coil primary, secondary, plug caps resistance.

- install a new set of NGK D8EA spark plugs, properly gapped.

- check and adjust camchain tensioner.

- check and adjust valve clearances; record your findings. http://xjbikes.com/Forums/viewtopic/t=14827.html

- check engine cylinder compression; record your findings.

- install in-line fuel filter.

- check function/operation of fuel petcock; correct any leaks and/or rebuild the petcock if indicated. http://xjbikes.com/Forums/viewtopic/t=25058.html

- clean carbs thoroughly, replace any worn or dried-out rubber parts.

- wet-set the float levels using fuel and clear tubing as specified in the manual. This adjustment has a 2mm tolerance so it must be done carefully.

- do a careful and accurate bench sync on the carbs before reinstalling.

- perform a running vacuum sync with the YICS blocked.

- adjust mixtures as needed.

After all that (and having corrected anything and everything that needed attention along the way,)

It'll run like a top.

Nothin' to it. Go find a manual and welcome aboard.

 

Whoo Whee! That is a checklist! If you do all that Yamaha might certify it as new AND allow you to race it on their factory team, but he is absolutely right. Take your time and go through it. You'll learn a lot and love your bike when it is done. If you really want to learn about carbs try Pods. :lol:

 

That's the SHORT list.

 

remove side cover, remove four screws on air box to expose air filter, remove air filter, spray a very little bit of quick start into air box, move to side of bike where air box is exposed, half choke, turn on key, push electric start button. if engine fires up then begins to die spray another short blast ( very short ok ) of quick start - if engine regains rpm your problem is fuel delivery - if it doesn't regain rpm your problem is somewhere else ( be CAREFUL when using quick start ( spray once or twice only for the test ) since it is not only extremely flamable, it also can cause engine damage since it washes the oil off the cylinder walls - this is what I would do and have been using this method of determining if fuel is being delivered to cyclinders on many engines with no damage -the decision is yours alone - if you try it let me know how it works out - good luck

 

That's an amazing amount of information.

 

I speak from experience.

So get busy. You DO want to actually ride/use this bike, right?

Look at my sig; check my gallery. I put 5300 miles on the black bike last season. The 550 will return 52~56mpg when properly tuned.

The biggest investment you'll make is TIME. The few hundred dollars you'll spend along the way are nothing by comparison.

You have some work to do. How about some history on this bike, like its mileage, and some PICS???