Ok, need help xj550

Ok so i need help getting my 81 xj550 running. Have tried before without success and put it on the back burner.
It will sometime fire and start, runs good for a few minutes, then dies. It might do this a few times then won't fire and start anymore until the next time it decides to run. New coils, wires, and plugs . Battery reading 12.5 volts on new battery installed yesterday. Drops to 9.6 when starter is turning. Some say it needs 10 volts. Anyway, what to check?

 

Can you give us a little history about the carbs? Sounds like it is starving for fuel?

 

Ive cleaned the carbs before. Seemed to run good when it was running. Seens I'm back to a no fire situation.

12.5 volts on battery. Had it on a 1.25 amp trickle charger overnight. Drops to 11 volts when starting. Its no longer firing at all. Checked by grounding plug and spark tester.

All fuses check out good.

The other day i did find the 8 pin connector under the seat was burned at the red ignition wire. I wired that wire around the connector for trouble shooting.

 

Update. Well apparently both my coils have gone bad. Testing open on the secondary coil.
SCRATCH THAT!! I was testing them wrong. The coils are good 2.8 on the primary and 12000 on the secondary. All the caps test good as well.

 

My clymer manual said to check the secondary by placing one lead on a secondary wire and the other on either primary lead. This is apparently an error and it seems you check the secondary by placing one lead on each secondary wire.

 

Yep. There are several errors in all of the manuals, and that is one of them.
Read The Information Overload Hour for the correct information.

Make sure that your meter is calibrated correctly (testing with a 9V battery works). Your motorcycle battery should have a resting votage of at least 12.8 volts, and not drop below 10 Volts when starting the engine. Even brand-new batteries can be bad.

 

+1 on kmoe
new batterys can be crap, if i can pay less than $100 CAN for a battery, im pretty leery its quality.
Remember, the bike isnt kick start, drop a few $$ on a good, name brand battery. (I like the AGM ones, good luck with top of the line NAPA brand think a new one for mine was around $140 CAN)
Clean all connections on pos n ground.
An old or poor solenoid, or weak starter can also be suspect.

 

I was rechecking for spark today. Battery reading 12.5. Drops to about 10.4 with starter turning. I kept noticing one or 2 weak sparks right when depressing the start button then nothing.

 

You have too much voltage drop to fire the TCI, did you check everything above? ^^^

 

Too much voltage drop? I've been under the impression from reading here that over 10 volts was plenty to fire the bike. Some have even said 9.5 volts. So if I'm dropping from 12.5 to about 10.5 volts, shouldn't that be plenty?

 

I've also tried with jumper cables from my car battery with the same results by the way. And yes, I confess that I did it quite a bit with the car running. That was with an old battery on the bike that would only read 2.5 volts and not take a charge. Hope I didn't burn something up.

 

Seems like you're chasing an ignition fault that doesn't exist. Move back to fuel. That's the real Achilles' heel of an old bike. Only takes a small piece of cr@p from a rusty tank to cause havoc.

 

My only concern with the battery is the low resting voltage when fully charged. It seems like the voltage drop is fine, but if it were my battery I'd want it load tested at a shop or to use another meter that I know is calibrated to be sure that the meter I've been using is giving me a correct reading.
That you saw an initial drop to 9.6 volts and are now seeing a drop to 10 volts says to me that either the battery has a problem, or your meter is not holding its calibration.

While some people say the 9.5 volts is enough to start the bike, it's not enough to reliably start the bike. Part of how a TCI works results in there being a increase in voltage to the ignition system when the starter button is released, and that can be just enough to allow the bike to start....sometimes. What you want is to be able to start it all of the time.

I'm not discounting that carbs could be an issue, but based on the information you've given I am not comfortable in ruling out the battery as either the source, or a contributer to the problem.

 

hook it to a car battery do not start car see if it starts

ohm out your pick up coils

also try a little starting fluid if it fires up then you may want to think about a fuel issue

that is quite a voltage drop for a new battery could be your starter needs to be rebuilt.

9.8 volts is the cut off point for the tci to fire

 

Being that a car battery has more cranking amps it shouldnt allow as much voltage drop, so...
Try running the booster cables from your car, not running, to the battery leads with the bike battery disconnected as a real dead or internally shorted battery can interfere, and If it starts battery is at fault.
If it doesnt start try hooking the negative direct to the engine block, if it starts this indicates a ground fault.
From there id try jumping the solenoid manually across the terminals with needle nose pliers, if it fires, bad solenoid.
After all this, id recommend tearing apart, rebuilding and testing the starter for shorts in the armature.
Side note: have you tried ether to be sure its not a fuel issue?

 

I work at an ATV/Sled shop, i see more people chasing electrical problems and burning out components because they have a cheap Wal-mart battery in thier machine.
Just this spring i bought a sled where the owner had burnt 2 voltage regulators, the stator, 2 solenoids and a starter.
(All at different times)
He had changed the guages because of issues reading and even the computer for inconsistant running problems at low RPMs... Eventually he blew it up because "it only ever really runs right wide open"
It had a Powermax battery, or something along those lines.
So a fresh motor and a $180 battery, it runs mint!
the old guages and computer even work fine when i tried plugging them in.
Just putting it out there!

 

The battery is a new cheap 40.00 battery. I
ohmed out the pickup coils and they were good.
11.2 olts with key on at the red/white wire at the CDI..
I had something like that at the connectors for the coils.
Checked and cleaned the ground to the engine off the neg bat cable and the 2 grounds behind the ignition coil bolt.

As a side note on the battery, I bought a new battery for my grand daughters chinese 4 wheeler. It's a little ever start battery from walmart. Put the acid in it, charged it for an hour and it was reading 13.4 volts!! My battery only charges to 12.5!

 

My batteries finish charge at around 13.5 then drop to a steady 12.5+, but of course us Europes have better Volts than you - we even invented them.

Seriously though, you tried a car battery and saw no change so my money is firmly on the fuel system.

 

I'll try the car battery when I get home today. Im pretty sure I have already with the new battery on the bike but really cant remember now.
I still dont think there is a fuel problem as I am still getting no consistent fire.

When it decides to fire it cranks and runs good. Ive let it idle for probably 10 minutes when it has cranked and i really don't think it would do that with a fuel problem.

 

Ok, so today I hooked up to my car battery and still no love. I still see no spark by grounding the plug. ( My eyes ain't very good though)

Anyway, I decided after the few suggestions to check fuel delivery. I only did a couple quick checks cause it was getting dark but here's some things I found.
I disconnected the fuel hose from the filter, left the vacuum line in place, held the line away from the bike and cranked over the engine. The amount of gas that came out when set to on seemed insufficient. Had good flow on prime, and decent flow on reserve. I have attempted to start on prime and reserve with no luck though. I haven't checked the fuel filter yet or the carbs.

I had no starting fluid so I sprayed a little carb cleaner in the airbox and the bike backfired, then next try it hit just a hair. Both of which tells me there's fire somewhere!

Also, I've noticed that when I crank the engine over, then crank the throttle wide open the bike turns over a fair amount faster. Why would this be?