Just picked up bike need help.

I just got 81 xj550 today and the battery was dead so i have had it on the charger for a while. I was able to get the bike to start and rev up a little the first time, after that i am only able to get it to run while the choke is on. The bike will run good until i go to either give it gas or switch the choke off, the carburetors were just rebuilt. What do i need to start looking for or checking?

 

First thing is to make sure you have sufficient fuel. These tanks look almost half full when they need to be switched to "RES".

The fuel valve can fail. Try setting it to "PRI". Make sure you turn it back to "ON" or "RES" before letting it sit.

Make sure that the air filter is in and intact.

If those are all good you probably need to rebuild the carburetors properly.

 

Synching carbs can cure a bike that bogs under throttle or idles roughly.
Its easy to do and does not require any major disassembly.

 

If the battery was dead from sitting for along time, try replacing the gas to fresh gas. Replace the gas in the tank, drain the float bowls and charge up the battery.

Sean

 

Is that covered in the manual?




I also found part of my problem, i took my multi-meter and checked my charger and found it working only half the time. So i just got back with a new charger going to let it charge a little while then try it again.

 

ok i got the bike running with the choke, i can turn the throttle just a hair and it will rev a little bit. So i let it run for about 5 minutes on choke and doing the same thing still will not let me take the choke off or give it gas. I set the fuel to RES and saw no difference. Synching the carbs, how do i do this or is there a "how to" on this forum?

any help would be appreciated

 

Regarding your charging system-

The alternator only begins to put out power at around 2k RPM's. Well above idle. You actually draw from the battery when sitting at idle. Might want to check again.

 

ok i didnt know that, but my charger(when i say charger i mean my trickel charger) was crap. I checked it w/ my multi-meter and it was putting nothing out. You could touch the + and - together and get no spark


im now able to crank it everytime with the choke, but dies when i turn it off or try to give it gas.

 

that could mean that the carbs are getting cleaner as gas is going through, throw some seafoam or another good carb clean in the tank, and see what happens

 

First and foremost, make sure your fuel and all of its delivery systems are clean and free of debris and/or contaminants. If the blood is pure, the heart (carburation) is most likely at fault. Don't mess with this problem if you don't know what you are doing. Synching carbs isn't as easy as others would make you believe, especially with the fickle Hitachis you've got on your bike. If you don't have an intimate knowledge of what it takes to make these carbs perform properly, find someone who does. If you really love your bike, it will be money well spent.

 

Here is the carb synch FAQ

http://xjbikes.com/Forums/viewtopic/t=2132/start=0.html

Its also in the Haynes manual.

Look in my gallery for the bottle synch that I built. I believe they work better than the meter.

You should read all of the FAQ items written by RickCo and Gamuru.

 

ok yea im not to experienced with carbs, i will prolly take it somewhere to have them look at it. I will try the seafoam first to see if that will cure the problem.

So when the bike idles on choke it is erratic doesnt really stay at any certain RPM, is this normal?

 

If idle is erratic you have an air leak.
There are threads about that recently.

If you have someone "look at it" you may get crappy service and spend a lot of money.

I never synched a carb before or rebuilt one. I just followed RickCo and Gamuru's FAQ posts. I spent two days tearing apart the carbs and cleaning them and then synching them. Its no more difficult than building Legos.

 

Yeah, really SMALL soft metal legos that screw together.

 

They are a challenge but very do-able.

I was petrified to tear them apart but after reading the very well written instructions in the FAQ it was not a big deal. Its a lot of time to do it but you are saving hundreds of dollars by doing the work yourself.

In addition you now have a skill that can save you money later or can allow you to ride a motorcycle that someone else would throw away.

Its recycling at it best.

 

First off, if it's an XJ550, it has Mikuni's, not "fickle Hitachi's". Sounds like your pilot jets might be plugged. A classic symptom is to only run with enrichener ("choke") on, idle super-fast, and die when you turn the enrichener off. (sound familiar?)
Understand that the enrichment circuit works by providing more fuel, not less air, as does a choke.
Your pilot jets provide fuel flow to the idle circuit of the carb. Plugged pilot jets=no fuel=no idle. Make sense?
The good news is that the pilot jets can be cleaned very easily by removing the float bowls, pulling each pilot jet and carefully cleaning the pinhole passage with a strand of SOFT copper wire (anything you use MUST be softer than the brass the jet is made from!) and Gumout Jet Spray carb cleaner. Clean the jets, bowls, and the passages they screw into. Reassemble, reinstall, and the bike should run.
Now that I've told you that, I'll get to the point and tell you that you really should do a complete carb strip & clean per the EXCELLENT posts on this site. Because you'll end up needing to do it sooner or later. But if you just want to prove to yourself that this IS the problem, have at it.

 

Yes the symptoms you are describing sound like mine, although tonight the bike idled pretty good on choke. Looking at the carbs, looks like they are a pain in the ass to get out?

Another issue i found is the petcock. I do not get fuel with the valve on RES or ON (i used suction on the valve and get nothing) so i need to clean the valve. But even with the bike on PRI i get the same result as you are describing. I will have to tackle that this weekend. Thanks for your help.

 

Not as bad as you'd think. It helps loads to warm the boots with a heat gun or hairdryer to soften up the rubber (use caution not to overheat; have fire protection nearby!) Drain the float bowls before trying this, naturally! Using a hunk of 2X4 as a wedge between the carb bank and cylider head will ease popping the carbs out. It's really not as bad as it looks. It's actually harder to get them back on, but you can cross that bridge when you come to it!

 

Have you validated that all four cylinders are firing. A quick check, is to get your hand near the header pipes to feel for heat. You also could check for good spark when turning the engine over. I fought my carbs for a week, only to find that I had a weak coil. A torn carburetor diaphragm would also cause rough idle.