85 XJ700 Won't Start (No Spark)

I have a 1985 XJ700. When I got it, it worked great. I was riding it back and forth to work with no problem. One day after I got home from work (riding the bike) I went to run an errand on the bike but it would not start. I thought this was odd since I had just been riding it a couple hours before. After some investigation I realized that I was not getting spark on any of my cylinders. After a little more troubleshooting I noticed that I am getting a consistent 9.99 volts from my TCI (Red/white and black wires) with a fully charged battery before I hit the starter, and around 10.25 volts after I hit the starter. After reading some other forums this seems to be marginally enough (most say you should have at least 10 volts). It was suggested that I check my fuse box (behind the neutral light), kill switch, and ignition switch. I was able to temporarily bypass the ignition switch using jumpers to rule out the possibility of it being bad. The problem persisted. My kill switch has less than an ohm of resistance. The fuse box though old and cracked seems to be pretty corrosion free. Does anyone have any input on other things I should look at or ways to investigate what I already looked at further? Any advice is welcome. I am anxious to get this thing back on the road!

 

Hi claycing. Couple of quick questions that may help....

Does connecting another battery, via jump start, help? You also mentioned the fuse block is cracked, how badly and are you certain they are not contributing to the issue?

 

Not that familiar with the 700 wiring but I'd suspect it's a safety or a fuse. Check across all of the fuses for voltage. The side stand relay often cause issues like this, either flakey coil/contacts or the switch itself going to the relay.

 

Its a brand new battery and even with the jumper cables connected it has the same problem. i don't believe so the cracks are mostly in the block itself not near the fuses.

 

It is cranking wouldn't the side stand switch keep it from cranking? I really don't know that's just how I understood the system I could be completely wrong though.

 

Usually it won't crank but again I'm not 100% familiar with the 700 wiring. I just remember the TCI being tied to neutral and side-stand interlock so suggested looking there.

 

Ok thanks! Ill add that to my list of things to check

 

The sidestand switch is not needed for the bike to crank while in neutral or to enable the ignition cutoff as the neutral switch will do both. However, you could have an issue with the ignition cutoff safety circuit caused by the sidestand relay, or the associated wiring. You can test the sidestand switch by placing the bike in gear and pulling the clutch in, if the bike cranks the sidestand and clutch switch are working. You can temporarily disable the ignition cutoff by disconnecting the sidestand relay, which is located under the left side cover and marked with a blue dot.

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

"XJ700 and XJ750-X models:

Flasher: combined into the consolidated relay assembly unit.
Flasher canceller: combined into the consolidated relay assembly unit.
Starter/Ignition cut-off relay: combined into the consolidated relay assembly unit.
Consolidated relay assembly: behind the gas tank on the frame tube cross-brace.
Starter motor solenoid/relay: attached to and centrally behind the battery box.
Sidestand (kickstand) relay (blue): under left side cover, above regulator.
Headlight relay (yellow): not used.
Main fuseholder: behind frame crossbar, behind the battery.
Diode block: under left side cover, above regulator.
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"."
Thermo unit: screws into the thermostat housing.
Thermoswitch: screws into the thermostat housing.

 

I am having the no spark on any plugs problem. I feel like i have pulled appart and cleaned just about every connecter. I am only getting 10.5 volts from the red/white and black wires on the tci. Any other ideas?

 

I haven’t seen where you’ve done a voltage test on the battery, and a voltage drop test when hitting the starter. I know you said it’s a fully charged battery. But that doesn’t mean the battery is any good. I’ve seen numerous brand new batteries that were no good. Long and short of it is that I’d go to the battery first.

 

+1 ^^ You beat me to it

I don't see any coil testing numbers? Have not cut off the end of the plug wires a little yet? I would start with the simple things and if that all fails then you can start to check and or open up the TCI to check it.

 

What is the second thing about the plug wires?

 

I'm pretty sure it's fine but i will check again. I have also been doing a lot of these tests with a jump pack to hopefully rule out a weak battery, would that make any difference?

 

Umm, yeah!

 

Unscrew the plug caps from the wire, snip a bit off to get a better connection. Over time the pointy end of the plug boot will wear away the shield and graphite core causing intermittent spark issues.

 

ok so I've been doing that haha

 

ok I'll give that a shot. My only thing though is I'm not getting spark on ANY plugs, and it happened suddenly. Would the plug wires all go out at once to cause a problem like that?

 

Probably not, but you never know. Regardless, weak spark is already an issue on the XJ systems and a bad boot connection makes it worse. The coils checked ok? Check the resistance on both the primary and secondary windings.

 

I wonder if the brushes in the alternator are bad or got contaminated with oil. Mine did, and I had starting problems. Replaced them and all is well. Perhaps one of the online gurus will know how to test them without having to remove them. If one of the brushes broke or got stuck that could account for the sudden disappearance of a spark--or at least I think it could.

 

ok this is the first bike ive worked on so ill have to do some research on how to do that