Electrical HELP

Here's my problem. My 81 XJ550 runs fine and will bump start great. (Obviously Getting spark while it runs) but when I turn it over with the starter I get NO spark. at the last second when I release the start button and the starter dis-engages I will get one or two parks while the motor turns over for the half second that the starter is disengaged. When it's warm I've gotten it to start this way. Just turn it over for a second and letting it start on the "slow down". So what would cause there to be no spark only while the starter is engaged. FYI I replaced the starter and battery.

 

could be the charging system may need to replace brushes in th alternator. when did you put in a new battery? do the tests below and let us know the results.
if it is your alternator you may get stuck someplace. do you use a battery tender?

check your battery standing voltage.
fluid level add distilled water to fill battery
also starting voltage if battery drops below 10 volts when starting it will not fire
hook meter to battery check voltage
press starter check voltage

100% Charged:
Using a syringe Hydrometer: 1.265
Using a Digital Voltmeter: 12.60 volts
Using a Floating-Ball Hydrometer: 4 balls floating
charging voltage
For all XJ-series models, the maximum available charging output VOLTAGE should be as follows (all values are approximate):
* approximately 500-2000 rpms: 1.8 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts

 

welcome to the site together we can answer all your questions
some good info for you
1) I would read through the information over load
The Information Overload Hour

2) then church of clean
IN THE CHURCH OF CLEAN

3) compression test have you done one?

4) valve clearance have you checked this? you will need KD 2274 metric feeler gauges any auto parts store can order with this numder
AIRHEAD VALVE ADJUSTMENT with Pics

5) do you have a manual? sign up on this site www.4shared.com
http://www.4shared.com/rar/W7QZie6f/Yamaha_Xj550rh_Service_Repair_.htm

http://www.4shared.com/rar/VPkftmDj/Yamaha_Xj550rh_Service_Repair_.htm

lots of info thread at this link he is a parts supplier to
http://www.xjbikes.com/forums/forums/xj4ever-supporting-vendor.23/

this link too
http://www.xj4ever.com/downloads.html

wiring diagram book mark it
http://www.frankjohansson.com/stuff/xj550/XJ550ElectricalDiagram.html

 

Thanks for the reply. I can do the test tomorrow. I never thought to do that, because I've tried starting it till the battery won't turn the starter anymore. Then I've bump started it, road it around and then the battery was charged, easily turning over the starter. So I assumed the charging system was working fine.

The battery is brand new.

 

Welcome to xjbikes

Even though your battery is new doesn't guarantee that it is good. A weak battery will have plenty of power to spin the motor but insufficient voltage to produce a good spark.

XJ550H gave you lots of good info. The links cover many of the problems with these bikes as well as providing a good understanding of how things work. With some reading and some questions you can make your XJ a safe and reliable ride. And, just in case you have not found it yet check out step 3 from the "Information Overload Hour" as Chacal (Len) describes your exact symptom.

http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

3) if you run into this specific problem:

* "There were a few times when I cranked it, that it ALMOST started. It would start to fire immediately as I let off the start button. But it just wouldn't catch.

Then this is a symptom of a weak battery, due to any number of causes.......

What happens is that as the starter is being engaged, it gobbles up battery voltage. As soon as the start button is released, you now have full battery voltage available TO THE IGNITION CIRCUIT (including the pick-ups, the TCI, and especially the coils), and in that instant when you release the starter button, the coils get enough voltage to produce an adequate spark while the motor is still (by inertia) turning over. If everything is in a great state of tune, the bike will normally kick over. If not, you get the "almost fires" situation explained above, so.........

Test the battery voltage WHILE THE STARTER IS ENGAGED (a voltmeter across the + and - terminals of the battery is all that's needed). It should remain above 9.5 volts while the starter motor is engaged but without the engine running. If it drops below that level while the starter is active, then that's the "problem", and the cause of that problem must be determined and remedied (usually a sign of a bad battery, or it could be a incredibly problematic starter motor).

 

If you have the original fuse box (glass fuses), you should probably also replace that (Len has replacements). Those fuse clips oxidize get brittle, and lose conductivity where they contact the fuses. The high current side of the starter circuit does not go through the fuse box, but the solenoid coil does, as do other things that may be dropping more voltage while cranking.

The other other thing to check is the ground strap. If you measure from the - post of the battery to the crankcase while cranking, you should should not see any significant voltage (probably less than 0.1V). If you're dropping more than that, you may need need a new ground cable, or you may need to remove it and clean up its contacts with a wire brush.

 

also disconnect and clean, both battery terminals and leads, starter solenoid connections ,starter motor connections and grounds
stu

 

is there a safety relay that disables the ignition but lets the starter run ?
just a thought, i haven't had relays for years.

 

I had the same problem. Try to jump it with your auto battery. If it starts your new battery is probably bad.

 

Charging system tested and it checks out. I'll do the drop test while starting next. As well as the battery to ground test. And if time allows probably upgrade to a new fuse box this weekend.

Is it possible that the batter may be good but just not enough CCAs or generally not big enough. I had a hard time finding a battery that would fit in that battery box. Could anyone recommend a good battery for the bike.

This also reminds me that I have tried starting it with a battery charger hooked up on start mode. I would think that would make up for a small battery. But maybe I'm wrong or maybe that points to the resistance do to currosion thing.

 

This is kinda what I was thinking. The amount of safety relays on these bikes are ridicules. I've always thought if your stupid enough to start it with the clutch out and in gear, than you shouldn't be riding a motorcycle, or you'll learn you lesson quick... And if your are starting your bike with no oil then you really have problems. But I guess the manufacturer wants new riders to buy their bikes so they have to protect them from themselves.

I'm going to try this.

 

if bike is turning over you are not being defeated by a safety relay.
cleaning connectors and using dielectric grease on them and relay contact points helps too ( no grease) . relay cover pops off

the oil light also comes on when riding to tell you oil is getting low it is a good feature if you start leaking oil on a ride . do not want to find out the hard way you have no oil

 

Also look into the ignition switch itself as it is a weak link where you can lose voltage since all the current has to flow through it to energize the fuse box

Take it apart and clean all the contact surfaces and reassemble with dielectric grease
This alone could add up to 1/2 volt at the fuse box

 

Classic symptoms of a bad battery

 

Charge your battery up and bring it to your local battery supplier. They should be able to "Load" test it to be sure its bad. If it checks good then look your cables and other connections including the starter solenoid.