Power will not turn off - Help

Hi List;
When I turn the key to the off position the power will not turn off on my 85 Maxim X (XJ750XN). Here is what I have done:

1 - I tried a blow dryer on the ignition - the power still will not turn off.

2 - then I sprayed a little WD40 in the key hole and let it sit in the hot sun all afternoon - still would not turn off

3 - then I tried spraying electric contact cleaner in the key hole and let it sit in the sun all day today - still will not turn off.

4 - I pulled the fuse for the ignition (under the instrument panel). Fuse looked good. Swapped it out with a couple of different ones - still wouldn't turn off. It didn't matter if the ignition fuse was out or in place the power would not turn off.

Where do I look next? Is it the ignition? Is there another fuse to look at?

Thanks in advance for any advice / suggestions.

 

I gather that your bike has got very wet for some reason.
If water has got down into the ig-switch, you may have to take it apart to dry it out.

 

Yes - I never had any trouble with the switch in the past. I washed it late last Thursday. Started it up and let it run for a few minutes then put it in the shed where it stayed until Wednesday morning. It started a little rough yesterday morning but when it warmed up it ran fine. When I got to work I turned the key to off and the power stayed on. I had to pull a battery wire to kill the power.

 

right side controls, rocker switch, run/off, main fuse=no power anywhere
the electrical contacts in the ignition switch are separated from the key part
i don't think spray makes it down there, take it apart

 

wiz is right... you will need to pull the ignition switch assy.

to get yours off...

remove the 2 large retaining screws that are attached to the headlight bucket. NOT on the ring itself

once you pull the headlight, disconnect it and set it to the side.
in the bucket is a 10mm bolt. pull that.
remove the lower bucket retaining bolt/nut attached to the triple tree.
move the bucket over and you will see the 2 bolts holding it on. pull those and when you lift the switch out, you will see 3 wires running to the bucket. unhook the connector and pull the switch out.
there are 2 screws that hold the switch to the back of the rear casing. undo those and the disk will come out. dry that off and put on some dielectric grease. put it back together and it should work for ya.

 

Looks like I will be pulling the ignition switch tomorrow night. Thanks for the replies and thanks for the instructions Helmet. I'll post back what I find.

 

Agreed, you need to open up the switch.

Contact cleaner won't solve the problem. Your problem is something staying connected that shouldn't.

 

I pulled the ignition switch from the bike. When I unplugged the ignition switch from the wiring harness the power stayed on so it is not the ignition switch. Since I had the switch off anyway I pulled it apart and cleaned it. It was in good condition and dry. What do I do next? Can I assume there is a short in the plug on the wiring harness? I really don't want to start cutting wires. Can I use a meter to test the plug on the harness? What would I be looking for?

----------------------
1985 XJ750XN Maxim X

 

if the power stays on, there is a stuck relay downstream. I dont have the diagram for it or I would let you know what relay is sticking

 

What diagram do you need? I have the service manual from the XJCD. Here is the wiring diagram.

http://picasaweb.google.com/felixmcc/XJ ... 7352855810

 

From this wiring diagram, the only culprit (assuming you didn't swap any connectors around or jumper any wires together before the problem started) is the rectifier/regulator (2 on the diagram). That's the only place besides the ignition switch where Red (battery +12V) could get connected to Brown (switched ignition +12V). Try unplugging the rectifier/regulator and see if the problem goes away.

 

There is no way the regulator rectifier could be causing that problem. It has no moving parts, or anything to become stuck. And there is practically an entire wiring harness where those two wires can become shorted to each other. And of course disconnecting the regulator rectifier is going to make the problem go away. It would make any problem go away as the bike would no longer be getting any DC power at all.

 

OUCH ! never say never

 

Can you say "shorted rectifier"? It's not a moving part.. but, then again, most electronic parts aren't moving parts.

DC power for the bike, when it's not running, comes from the battery, not from the rectifier/regulator.

I look forward to hear the solution from the owner, once he finds it.

Paul

 

It is virtually impossible for the regulator rectifier to be shorted in the manner that you describe. If it had shorted the way you describe, the thing wouldn't work anymore, and he wouldn't have been able to ride to work on battery power alone, and then continue to be able to troubleshoot with that uncharged battery.

Not to mention, in order for the regulator/rectifer to have become hot enough to short those two channels together, it would have melted the wiring harness and probably the connector, as the R/R is designed to operate at a much higher temperature than the wires and connectors can handle.

There are several relays on these type bikes, they all have moving electronic parts.

 

I would say, no. Although it is arguably not well defined, electronic generally means devices without moving parts or devices that use active parts such as semi-conductors or vacuum tubes. I would say relays are electrical but not electronic.

Anyway, as I understand it, your theory is that the R and Br are shorted together somewhere in the harness. Mine is that one of the rectifier diodes in the rectifier/regulator itself is short (thus jumpering R to Br). I don't see why you think shorting out one of the rectifier diodes is so unlikely... it can happen pretty easily if someone hooks up a battery or jumper cables backwards.

There's also the third (and fourth) possibilities that we are both misunderstanding the issue described by the owner, or that the owner is not correctly describing what's happening.

Until he posts an update, we'll just have to wait and see.

Paul

 

Thanks for all the help.

The problem turned out to be a short in the ignition plug on the harness side between the red and the brown. The plug looked fine from the outside but the two were making contact inside the plug. I don't think they were actually touching, just close. I fixed the plug so that I now have insulation between the two connectors.

I tested the battery and got a reading of 16.8 volts disconnected from my bike.

I hooked the battery back up and fired up my bike. At 1200 rpm it was holding steady at 19.2 volts.

I pulled the battery and there was hardly any fluid left in it. I topped it up.

I went to pull the regulator and the plugs were all melted. I had to pry them apart with a screw driver.

Here are some photos:

http://picasaweb.google.com/felixmcc/RectiferPlug#

The plug on the wiring harness is a little worst.

I tested the rectifier and if I am doing it right it appears to be fried. The service manual (charging system - page 7-23) tells me I should be getting continuity from red to all three whites. I am getting a value of 1 on all ( no 0's).

So I guess I'm shopping for a rectifier / regulator tomorrow.

Regards;
Felix - 85 XJ750XN (Maxim X)

 

I would say we aren't exactly discussing solid state electronics on a 1980s motorcycle. On the type bike being discussed, there are electro-mechanical devices in play. Time and technology has advanced while the bike has not, so that is a moot point. It doesn't matter how you try to technically define it.

And I never posted a theory. I simply stated that your theory was not likely while offering feasible alternatives. Fact of the matter is, compromised wiring insulation, or sticking relays, or bad connections at other parts of the bike are for more likely to be the cause of the problem than a short in the R/R.

 

Does your meter have a zero feature? Your voltages sound correct respective to each other, just on the wrong scale.

Also, you have to do two different checks in order to properly test the both the regulator and the rectifier sides of the R/R. You should have little to no resistance between each of the white wires and the black wire, and again, little to no resistance between each of the white wires and the red wire. But when you swap the polarity of the test leads you should get high resistance between the same wires as before. On my bike, I get close to 300 ohms in one direction, and 0 in the other. In order to test the regulator side, you need to check both the brown and green wires while using black as the common. If you are truly getting 16 to 19 volts coming out of the green and black wire check, you do need a new R/R as the high reading should be between 14.4 and 14.8V at higher revs.

 

I am new to multi-meters. I am setting the meter to Ohms and using a setting of 20k. I am attaching the red lead to the red wire and the black lead to the white wire. Here are some photos:

http://picasaweb.google.com/felixmcc/Dr ... NjdpI2OBg#

I am getting a value on 1 on the meter. Shouldn't I be getting 0 for no resistance?

When I tested the volts while the bike was running I did it right on the battery terminals and received 19.2 volts at 1200 rpm's. Should I have tested it somewhere else?