runs for a second...

Hi XJ'ers,

Big problems.

New battery, new plugs. Fuses check. Coils ohm test ok, and sparks with plugs grounded. Starter motor brushes ok, and commutator cleaned. Alternator brushes look good. Solenoid clicking and turning the starter if I short the posts.

The bike will start up for a second, then nothing. If I leave it for a while, same thing but once only. After that, just the starter turning. And that's it. Removed the starter relay, no difference.

I'm assuming it's electrical because I had to remove the headlamp shell for painting, so all connections were apart. Because it's modified (no clutch switch, sidestand switch) there are a lot of loose bits of wire in there, and scraggy insulating tape. I noted it all down, but lost the freaking piece of paper

Suggestions please. In the meantime I'm going to take a break from electrics, and pull the carbs, just in case. The bike was standing for a few weeks. But I don't think so.

Thanks in advance.

 

oops - that should say - 'removed the safety relay', not the starter relay. sorry

 

You need to "Jumper" the leads that would have terminated at switches related to the safety circuitry.

Clutch lever switch.
Sidestand.

Each of those switches have plug-in pigtails. Undo the quick-connections and jumper the connections on the harness side. With the safety circuitry bypassed, the bike is configured to let the Starter Motor operate when the Start Button is press with the Ignition ON -- regardless of the bike being in gear with the Clutch Lever NOT pulled.

My experience trouble-shooting Side-stand and Clutch Lever safety switches indicates that it is rarely the "Electrical - Switching" part of the switch that fails.

In BOTH cases; the switches develop problems that are "Mechanical" in nature.

The Side stand switch's activating rod binds within it travel limit due to contamination building-up preventing the rod to move ... either at where the rod engages the top of the sidestand, in the small passage drilled near the hinge bolt ... or, in the passage on the switch, itself, where the rod extends into the switch body to open and close the switch. Cleaning and burnishing the end of the rod to a near polished, friction-free, surface usually fixes that problem.

The Clutch lever switch's -- very small, plastic, "Activating (rod, tab, protuberance, et .al.)" ... becomes deformed -- and/or -- worn down.
In the case of it becoming deformed; that little activating end becomes curved and binds within the switch housing -- or -- when severely deformed, pushes the switch body rather than moving in and out as it should. "Shaving" to "square-up" the tab and firmly securing the switch body with a small (miniature) plastic tie-wrap; can cure that problem temporarily.

 

Thanks Rick. I have to go away for a couple of days, but will get back to this on Wednesday. New job, new city.

However, I'm certain the clutch switch was decommissioned long ago, and almost certain same goes for sidestand.

I searched through all your four-hundred-and-something posts this morning, because in the back of my mind was something you responded to a while back. It seems to resonate with what I'm getting now - ie brief firing, then nothing, then momentary life again after a rest.

Any other thoughts appreciated. Thanks.

 

Did you use any choke when starting?? It takes a couple of tries for my bike to get started with the chocke partially on. SOmetimes i add a lil bit of throttle to start it (left hand on start button, right on on throttle).

 

Hi,

Yeah tried every combination I could think of... frustrating. Will be back on the case on Wednesday, hoping for the best.

 

SOLVED !

Very simple really. The run/kill swith was filthy, and rather waterlogged too. Bike now actually sounding better than before.

Switch apart, cleaned, and back together in less than 15 minutes... not counting the 5 or 6 hours I had spent chasing more complicated possibilities, with a brand new multimeter bought specially.

Lesson learned - do the simple stuff first. Connections, switches, fuses.

Still, at least I know the alternator brushes are good; the starter motor brushes too, commutator cleaned, gears packed with fresh grease.

Thanks as usual to all who replied.

 

Glad to hear you found the issue! K.I.S.S. is a great acronym, my instructor used to wallop us upside the head with it. Don't fret about purchasing the multimeter, it will pay for itself in time. Besides, the practice will do you no harm.