Electrical/Starting Problem

Good morning. I have a 81 XJ650 Maxim that I've been riding for about 2 years. Never had a problem starting other than a low battery until this week. With a charged battery I turn over like a champ but won't catch. I'm fairly certain I have no spark as spraying starter fluid into the spark plugs resulted in nothing. I've checked fuses and everything seems to be fine. However, I think it's an electrical issue since the headlight won't turn on when I turn the key, the brake light is always on, the turn-signals won't work and the neutral light is working on/off. Any suggestions?

 

that's alot of symptoms! physically check for spark with the plug grounded to the head. Play with the signal switch or take it apart, take out the headlight and check for loose connection. could be the side stand relay too. Got a manual?

 

yamaman, i'm eliminating symptoms as i work through the electrical and ignition systems...fixed the light/signal problems - bad connection at the fuses that was fixed by a little cleaning.

i've gone through some of the steps haynes has recommended for a faulty ignition system:
- check entire ignition for connections - all look good
- check battery voltage and specific gravity - voltage good, don't have a hydrometer to ck gravity
- check fuse & fuse connections - all test fine
- check resistance of ignition coil - fine

I've not gone to the next step of checking the pick-up coils just yet. I got a new battery that's currently charging. In another thread I read that even a battery that tests fine, may be the problem. Since the battery was pretty much dead when I bought the bike, was able to bring it back to life for the past 2 years, I'm thinking it didn't hurt to change it at this point and eliminate it from the list of potential problems.

Any other suggestions, would love to hear them. Thanks!

 

Not sure you have a diode block on the 81 - if you do give it a check. Have you checked the regulator?

 

the battery thing is very true, also could be the starter motor brushes, if they're worn they can draw to much, easy to check the lengths as the manual says.
Keep us posted

 

Let's start with the middle and work outwards:

Check for 12V between the R/W and Black wires of the 4-pin TCI plug while cranking. It might drop to 10V or so when cranking, but shouldn't get any lower.

If you don't have 12V here, then you have a problem with the ignition switch, fuses, or wiring.

BTW, I don't think you have this on your bike, but, if there is a B/W wire going to the TCI, make sure it is floating relative to ground. If you read continuity from this wire to ground, then a safety circuit is disabling your TCI.

Lastly, on most of these bikes, the headlight is designed to not come on until the engine has been started.

Cheers,
Paul

 

Paul, did the test of the R/W and Black wires of the 4-pin TCI plug while cranking. Starts with 12, drops to about 6 while cranking, back up to about 8/9 when I let go of the starter button, about a second later there's a click and then it's back up to 12. I'm still on the old battery. Could this also be the result of an old battery?

There's no B/W going to the TCI....

Headlight...you're the second person to tell me that. I thought my light was on as soon as I turned the key, but it's quite possible I just am remembering wrong. I don't know that I paid it all that much attention.

Yamaman, if the new battery doesn't do the trick, that'll be my next step...

 

6 is too low.

You can check the voltage at the battery itself while cranking. If that also drops to 6V, then the battery's the problem.

If the battery voltage stays in the 10-12 range when cranking, then bad fuse, switch, or plug contacts are the problem.

 

battery drops down below 10 while cranking, but more like 9, not 6. i'll pick up a new fuse as well, just eliminate that as a potential issue. i've already gone through to clean the plug contacts and only one could have been an issue. i'll jump that if the battery and fuses don't work.

off to see some fireworks. will continue work on this tomorrow.

thanks!

 

If you still have the original fuse box, that's most likely the problem. The clips get brittle and oxidized.

 

As has been noted, the headlight isn't supposed to come on until the bike is running. The idea is that it would be pulling amps needed to start the bike and the battery is weak enough as it is.

Look up Gamaru's guide to testing the starter circuit. Go through it step by step.

You definitely want to check the spark plugs to make certain they are sparking

How long ago was it last run? If it has been sitting a month or more, drain the gas from the carb bowls and the gas tank, and fill it with a gas/seafoam mix, and let that fill up the carbs and and let it sit for a bit, then try to start the bike.

 

I have recently had the same problem, except i noticed before this issue that my headlight was always on and stil is as soon as the ignition is on

 

ok, we have the electrical sorted out. took everything apart, cleaned and put back together and we now have spark. there were a few connections that were less than stellar, starter motor was dirty and fuse panel is now all cleaned up and appears to be in good shape (haven't replaced it yet, Paul) still can't get it running. it wants to run now, but i'm just getting a lot of back-firing, i mean alot! delayed back-firing too! i'll stop cranking and a few seconds later it back-fires. any more suggestions? thanks for all the help so far!

 

Is it possible, in all the excitement, that the Orange and Grey wires (either from the pickups, or from the coils) got swapped? Or that the 1/4 plug wires might have gotten swapped with the 2/3 wires?

 

read some forums on backfiring and got it running yesterday. took it out for a quick ride and quite enjoyed a sense of accomplishment. thank you to all who helped. still have some issues i discovered while working on it that need to be addressed but don't have the time today:

1. signal fuse blows a few minutes into my ride. checked wires and connections and all seems to be fine. I guess it IS time to switch the fuse box as it's original
2. inlet rubber from carb on 3/4 cyl are starting to crack, messing up the air/fuel mixture

 

The rubber intake manifolds WILL crack, and horribly, without the cracks going all the way through. Don't jump to this assumption, the manifold bolts are too easy to break.

The fuse contacts will LOOK just fine but suddenly just break for no apparent reason. If you don't want to retrofit the fuse box right now, you can use fuse clips from Radio Shack and replace the stock clips with ones made from modern metals.