Humidity problems.

Ok, my 83 maxim has a weird issue that I can a not find a fix for. On hot dry days it'll fire up, run fine all day for hours no problem. On days cooler than 70 degrees the spark plugs won't fire and on days after it rains and it's a bit more humid than others I'll be riding it and it will kill as if I hit the kill switch and it will not start back up for about 20 minutes. As if the sparks aren't firing again like on the days under 70 degrees. It so frustrating riding on the highway and having it kill. I have no idea what the problem is or where to evan start looking. All the connections are fine and all the rules are good. Is this a common problem among the maxims?

 

You probably have cracked plug wires, or cracked coil housings. To confirm you can start the bike in a dark garage, or at night. If you see a lightshow, well...that's your problem.

 

a quick mist with a spray bottle on a good day may replacate the problem. I would try the dark garage first.

 

I have called a electrical guy about this problem and he was saying it could be multiple things, but wants me to look into the stator, he said they go bad commonly with the older xjs (His words) or possibly that there might be flooding in the carbs. I'm not to sure about the stator because i still have power to the lights, horn and turn signals. Doesn't the stator charge the battery? I'm not to familiar with the stator.

 

the stator is part of the alternator

 

start by ohming out your charging system info on how is in the

The Information Overload Hour


do the same for your ignition system

what maxim do you have??

 

Vin says it's a mid max 750.

 

No they don't.

Carbs flooding won't keep the plugs from firing, and you would have wet plugs, and it wouldn't be related to the humidity, and it wouldn't suddenly happen while you're already riding.

Your electrical guy does not sound like good source of help for this problem.


What were the results of checking the plug wires and coils for cracking?

 

I started it at night as well as sprayed around the coils and plugs with mist. However I did not see any light show or have it recreate the bike dying. However it did die on its own without the mist and struggled to start again for a few hours this time. I am going to check the ohms as XJ550H as suggested as well.

 

Ok let's look at a few things. Go ahead and check the ohms. These bikes came with the cheapest electrical connectors made by mankind. You need to inspect all of your electrical connections from the tail light all the way up to inside the headlight.
Unplug every connector and inspect the terminals inside to see if they are green or black with corrosion. Treat every good connection with Dielectric Grease or Tune Up Grease as it may be called. All auto parts stores carry it. If you still have the original fuse block replace it with a modern blade fuse style fuse block.
When you have your tank off, inspect the coils for hairline cracks and check the wires for any damage, cracks or weather checking. There is a central grounding point under the tank also. Inspect the wires and clean all of the connectors and treat with the tune up grease when you put them back on the stud.
Lastly pop the cover off of your TCI and inspect the soldier joints for cracks. Temperature can effect those connections if there are cracked joints.
Check your charging voltage at idle, and at 2500 RPM. If you are not getting the proper voltage at 25K you may need to look at the brushes in the alternator cover. I like to see anything over 14 volts at higher RPM's but I have a cheap analog meter.
I also suggest to look at the three wire connector from the alternator to the regulator to see if has any burning connections. If its an electrical issue going through and checking your connectors is always a good maintenance thing to do on these older bikes.

 

sounds like a bad coil to me.

 

I had a problem very similar to what you are discribing when bike finially died and would not start anymore I had a bad pickup coil and the resistors in the plug caps had failed one had blown apart the other was measuring 25 k ohms and all carboned up. it was plugs 2 and 3 and the bottom pick up.
I would get 10 miles out and stall I kept checking for an air bubble in my fuel line took out the filter. then near the end 5 miles and would stall at the same place in my test ride loop 30 to 40 min later it would start.
not saying this is your problem but that is why I suggested ohming the ignition system

 

Side stand safety relays are going bad and intermintly cutting ignition.

 

Possible, but in that vein it's more likely that the sidestand switch is sticking and being activated when going over a bump. Relays generally fail, and then don't return to working order without being serviced.

 

Temperature and humidity related no start condition, my money is on crappy connections and or bad coils.

 

or possibly the clutch safety switch is on the way out.
jump it out in the head light bucket at the connector as well as the

Sidestand (kickstand) relay:
- unplug the safety relay which disables the whole bloody mess but DO NOT leave it that way, fix it right!
Clutch hand lever position switch:
- jumper the wires (on the main harness) to each other, the circuit will think the hand lever is pulled in.

try this to eliminate them as possible problems
simple to do and 2 less things to chase in finding your problems

when you are sure it is not the problem put them back the way they are supposed to be

when the bike dies is the time to check plug wires ohms and pick up coil ohms plus coil primary ohms .
pick up and primary can be done from tci connectors.
if the resistors are cracked they may be going full open with the heat and arcing across the gap reducing your plug spark intensity

 

Obviously wicked witches have put devils in your TCI.(I apologize inside joke)Now seriously
awesome trouble shooting guys. The only thing I could offer is possibly there is short at the ignition switch. on the run side of the switch Either at the harness connection or in the bottom of the switch itself.honda has a small board the wires hook to.so far I haven't taken a Yamaha switch apart. So it might be different.anyway if it's not something already covered in the thread ....well when all else fails maybe an exorcism IS worth a try.

.

 

GO slow. Test one thing at a time. That really is the only way to be sure of finding the problem and fixing it. Be methodical.

 

Update: Today I changed the oil and checked the wires and plugs for spark. They did not have any. When I was finished with the oil, I hit the switch and it fired up. So I shut it down, checked the wire for spark with a screwdriver. It didn't have spark at first, then after a couple cranks it sparked at the wire. So I got it running and took it down the street and just as I figured it killed about 30 feet from my house. I took the wire out again and checked and no spark. So it's killing the spark at the coil whatever the problem is. I am going to look into all the relays before I check the coils. Still have to buy an ohm meter. All this troubleshooting is extremely helpful.

 

This is exactly what it seems is happening. I haven't checked the pickup coil yet. I'm not to familiar with the setup of it yet. Gonna have a look I'm the manual.

 

Are all four plug wires failing to have spark when the failure occurs?

 

Yes, all four wires loose spark when this occurs. But it is random when it happens. I'm starting to think humidity has nothing to do with it, but rather it was just happening during times of high humidity.

 

Agreed. What this means it that you can concentrate on everthing from the primary feeds to the colls, back.
I would verify that the sidestand switch is working both mechanically and electrically, and do the same for the clutch switch. The sidestand switches tend to get crap in them (making the plunger sticky) and will cut power to the ignition if you go over a sufficient bump.
If you still have the original fusebox you should inspect it very carefully for cracked fuse clips.
The TCI should be the last suspect.

 

I have replaced the fuse box with the block fuxes. I will check all these problem areas and post an update with what's find.

 

Start what k-moe stated by checking your connections to and through the fuse box.

Gary H.

 

Update: sorry it took so long. I have done a lot of messing around and troubleshooting as instructed. I have come to a possible conclusion that the relay 12R under the gas tank is causing the spark to kill. I replaced it with the relay 4U8-00 on the side of the bike and it ran without problems. So I went and picked up another 12R relay and started it and it still killed even with the new 12R relay. So the relay 4U8-00 will provide spark every time I crank and run it but the 12R will kill the bike after about 2 minutes. I've never had this happen in the first 2 years of owning the bike. I have never replaced any relays till now, Is this relay not the correct relay. According to the relay master guide here on xjbikes it's the ignition cutoff relay. Which kinda makes sense with something killing the spark.

 

Relay Assy (12R-01) 12R-81950-01-00


Relay Assy (4U8-02) 4U8-81950-02-00

relays listed for your bike two different relays
this link helps with relays
The Ultimate Relay, Switch, Sensor, and Diodes Guide
1982-84 XJ750 Maxim and Midnight Maxim models:

Starter/Ignition cut-off relay (no color): behind self-canceller, under rear of tank.

Sidestand (kickstand) relay (blue): behind the left frame side cover, on the plastic regulator-rectifier mounting plate

What do you replace the relay with that you remove from side of bike the 4U8 relay. if nothing this is probaly your problem


BY-PASSING SWITCHES AND RELAYS:
Starting/Ignition Cut-Off/Neutral Safety relay:
- unplug the safety relay which disables the whole bloody mess but DO NOT leave it that way, fix it right!

Sidestand (kickstand) relay:
- unplug the safety relay which disables the whole bloody mess but DO NOT leave it that way, fix it right!

basicly when you unplug the relay you bypass it putting the wrong relay in the position is the same as bypassing it.

PUT your relays back where they belong then remove the Starter/Ignition cut-off relay the 12R relay
and ride your bike to see if the problem goes away.

then repete process for the 4U8 relay

then remove both relays
you could have 1 bad relay or 2 bad relays

 

Replacing the starter cutoff relay (12R) with a side stand relay (4U8) will effectively disable the starter safety circuit. The relays have identical connectors, but are different internally and should not be swapped. Most of the relays are identified with a colored dot and a corresponding colored wrap of vinyl tape on the harness to ensure correct fitment. The starter cutoff relay is the exception to no color marking.

From Len's guide:

http://www.xjbikes.com/forums/threads/the-ultimate-relay-switch-sensor-and-diodes-guide.27543/

1982-84 XJ750 Maxim and Midnight Maxim models:

Flasher: near the steering headpipe, on right side frame rail, under the right side ignition coil.
Flasher canceller: under the rear of gas tank.
Starter motor solenoid/relay: attached to and behind the battery box.
Starter/Ignition cut-off relay (no color): behind self-canceller, under rear of tank.
Sidestand (kickstand) relay (blue): behind the left frame side cover, on the plastic regulator-rectifier mounting plate.
Headlight relay (yellow): not used.
1982 XJ750 Maxim safety relay single diode: outside the main wiring harness bundle, in the area just behind the fuel tank.
1983-4 XJ750 Maxim Diode block: inside the headlight housing.
Neutral switch: in a hole in the bottom of the crankcase, just "outside" of the oil pan, on the bottom of the engine, up inside a recessed "well".

When you replaced the starter cutoff relay (12R) with the side stand relay (4U8), and if you did not install a relay in the side stand relay position, then you disabled the side stand safety circuit and the TCI was always enabled. Therefore, if this was the case you have isolated the problem to the side stand safety circuit, which is made up of the side stand relay, side stand switch, neutral switch, diode block, and associated wiring.

When riding in gear, the side stand switch is totally responsible for engaging the side stand relay and opening a set of normally closed contacts to enable the TCI. The neutral switch is wired in parallel with the side stand switch through the diode block, so if the bike died in gear, but would restart in neutral, then that would point to the side stand switch. If the bike will not run in either instance, then the side stand relay or wiring becomes suspect.

So, in summary from some of the earlier post to isolate the problem:

Temporarily remove the side stand relay to disable the side stand safety circuit, does this fix the problem?

The clutch switch will not cause a shutdown of the TCI, it is used in conjunction with the side stand switch to start the bike in gear. If you have a working clutch switch, then you can use this as a troubleshooting aid. When the bike dies, can you engage the starter with the bike in gear and the side stand up, if so the side stand switch is working and is not the root cause of loss of spark.

The starter cutoff relay will not cause a shutdown of the TCI. It does exactly as the name applies, and shuts down the starter if the correct parameters are not met to safely engage the starter. Removing the starter cutoff relay will not bypass the circuit, but instead will just disable it unless a jumper is installed from R/W to R/W. You don't need to go there unless you are having issues with engaging the starter.

 

If the plug wires are cracked do you have to change the coil?

 

no you can splice in a new wire NGK makes a nice splice you cut existing wire back leaving some of the old wire and do the splice.


NGK--8083 Local auto parts store or link below
http://www.edgextremesports.com/store/NGK-Cable-Splice-8083.html?gclid=CJGBotzguMsCFdgegQod1zMHmg

or you can did out the old wire and reglue in a new wire . there is a thread on this someplace

 

http://www.xjbikes.com/forums/posts/257495/

 

If you splice, wrap self-amalgamizing tape around the remainder of the old wires to insulate it.

 

Thanks XJ, I ordered a set today!

 

I took the 4u8 relay out and am able to ride it with no problems. So this relay is probably causing the problem. I will replace it and see if the problemreturns.

 

it is the sidestand safety switch relay could be your sidestand switch is failing check it out

 

+1 Because of their location, the sidestand switches are prone to get grimy and sticky. Corrosion can also be a problem. I clean mine annually and use a dry-film lubricant.

 

Update: I think I bypassed the kickstand/neutral relay, my rubber cover was ripped and it looked like it was a 2 piece plunger style relay. I just left the relay part and took the second plunger out, that the kickstand hits, completely. I also tightened up my clutch cable because it was a bit loose. I noticed it seemed to get up and move better after that. I let it warm up for about 30 minutes and took it around the block about 12 times and it didn't seem to have problems with loosing spark again. but that don't mean the problem is fixed. I'll have to ride it a few more times before I can be sure.

 

You basically did disable the sidestand switch. If you don't have a repeat incident then you can pretty well assume that the switch needs at least cleaned out, or replaced. A better way to bypass it is to just unplug the switch. The way you have it now does leave the possability that it can trip the switch with a bump if there is enough corrosion in the switch.

Clean them is pretty easy, but does nto always work. Since the switch is cased in epoxy the only real cleaning you can do is to spray contact cleaner up into the plunger hole and move it around to loosen things up. The contact cleaner will spill back out when you tip the switch housing.

 

[QUOTE="A better way to bypass it is to just unplug the switch.[/QUOTE]

I did try this. But for some reason the bike wouldn't start all together in neutral or in gear.........least I believe I followed the switch up to the TCI biggest plug with two wires coming out to a ground and power I'm imagining?

 

I did try this. But for some reason the bike wouldn't start all together in neutral or in gear.........least I believe I followed the switch up to the TCI biggest plug with two wires coming out to a ground and power I'm imagining?

 

the side stand wires and a sky blue wire go to a connector above the lowermud guard to a connector then to the relay not to the tci. the wire you followed is from the pickup coils
both harnesses follow the same path under the motor and up the frame in front of the read plastic fender

 

What he said ^^