Electrical gremlins and exchanging the wiring harness

[bdouvill]

Hi guys,

I recently (last week) upgraded the rear shock of my B400. To remove the GSXR shock that I had, I removed the battery and its casing to have a better access so I disconnected the battery and the wire from the starter relay that goes to the starter motor.
After that, I rode for like 10 minutes without problem.

Monday morning comes, I attached my bagpack at the back, put all my gears and ready to go to work. Rode like 20 meters then boom, no more current in the whole motorcycle...

Put it back in the garage (removed my gears to avoid being to sweaty 20 minutes only after my morning shower), unplugged/plugged the fuses (that I did not touched at all during my shock exchange) and it seemed to be back. The motorcycle ran a little bit in my box. Put my gears (again), turned the key, turned on the ignition switch and bam... no more current (again)...

Got a little pissed off. Put the bitc... back in the box, removed my gears. Went back home, grabbed my favorite JIS screwdriver and some more tools, remove the battery cover and checked on the wires. I had to put the wire that goes from the starter relay to the starter motor in the correct position on the starter relay but that was it, I did not change anything else.

Guess what ;-) I put my gears on again, then this time, it started and worked almost fine. Only on the way to work, everything stopped for one second (I mean no lights at all on the dashboard) which most probably means there was no current running in the bike at all but I reached work and since that, it went fine.

I know from this forum that copper wires get degraded with time and also the wire section is a little bit small especially for the main power supply. I will not put myself into building a brand new wiring because I don't have the tools for that (and not sure I can find the default connectors as well) even if that would be interesting. My main harness is not in good conditions: some connectors have rust and the connector for the regulator has been cut. In my garage, I have another harness that should be in better condition (I still need to check that). Problem is from it comes from a 93 or 94 Bandit (not sure at all) that came from Italy so the European version and mine is a 92 version (also European version) and I believe that 91-92 models and 93-94 models are not strictly identicals. I believe there is at least an engine advance timing difference which makes the CDI not to be exchangeable between the 2 versions.

Does anyone know if I can use my 93-94 harness on a 92 B400?
Thanks a lot in advance for your answer(s) ;-)

[Squishy]

Did you check the main ground from the battery to the engine?
I would choose to fix/check the current harnass rather than replacing the entire thing. Way less time consuming.

[ventYl]

i have same opinion as squishy. while fiddling with your current harness was strictly localized to small portion of it you can hunt for gremlins in that part. getting no power at all suggests some serious problems with circuit continuity thus i'd check the battery too if it is in good condition.

[greg737]

Benoit,

Sorry to here your Bandit isn't running well.

Here's a question: How did the installation of the GSXR shock go?  How well did the GSXR shock fit?

Is there any chance that something (i.e. the new shock) is coming in contact with the battery or one of the other electrical components when you put your body-weight on the bike?  That might explain the situation you've described, in which the bike will start and idle but when you climb aboard to ride it fails.

Just a thought.  Best of luck getting this problem sorted.

Greg

[bdouvill]

Thank you all for your answers.

I don't think I did anything out of the ordinary. My guess is rather on some connectors. I only unplugged the battery and disassembled the starter relay and the fuse box from the battery box. Doing so, I believe I exercised some mechanical traction over the main harness connector. Since the day I got the issue, I experienced another time (again just for one second) no current at all when riding, scary stuff. I did around 100km.

So as a primary measure, I bought a spray for electrical contact cleaning (for what it's worth) and gave it a try. I used it last Saturday (4 days ago) on the battery connectors, the inside of the fuse box and the main harness (battery connectors and fuse box connectors). Clearly, it looks like it does nothing but who knows. I took care of plugging properly the main harness to the fuse box and ensuring the curve of the harness is not too tight. And we'll see... I rode for 60km since that, did not experienced the blackout thing yet, I hope I will not ;-)

I keep you posted.

[bdouvill]

I believed I was ok until last week when gremlins popped out again :-(

I can tell when/where it started. I installed a LED flasher relay but did not install the new LED turn signals yet. New relay has a ground wire that I connected to the frame through the one of the 2 screws that maintain the passenger seat to the frame. It worked ok in the garage and for the first 20km until when I stopped to a red light (hopefully) I got no more current in the whole motorcycle... I parked and noticed it was fine (?) and we I rode again, each time I used the turn signals, I had cut in power so I rode home without any turn signal.

Now I am thinking of a bad/intermittent ground issue. On the wiring diagram in the manual, the ground is made directly from the battery which is I guess connected to the frame or the engine. I have to check that and if there's some rust or grease there. Does anyone know how this is made?

Also, I need to try with the turn signal relay connected to the battery instead of the frame (which should not solve the ground issue if any).

I keep you posted.

[Squishy]

Now I am thinking of a bad/intermittent ground issue. On the wiring diagram in the manual, the ground is made directly from the battery which is I guess connected to the frame or the engine. I have to check that and if there's some rust or grease there. Does anyone know how this is made?

Yes the wire from your battery goes above your crankcase, it's connected directly on the mounting bolt of the starter motor.

[greg737]

Nothing, not one electrical component, is grounded directly to the Bandit's frame.  Everything grounds to the engine by way of the bolt on the starter motor as Squishy has pointed out.
 

[ventYl]

there are at least two good reasons to do that:
1) the bandit frame, being naked bike has very poor water protection so everything has to be designed with water presence in the mind. frame contacts would corrode and develop voltage drop quite quickly.

2) electrochemical corrosion, copper contacts bolted to steel frame would cause steel frame in the contact with copper part corrode when current is flowing through it. this isn't as bad with contacts which are well covered but here it should be really bad. this is the reason why some vehicles have + pole grounded (corrosion eats the part which is connected to negative potential). also corrosion depends on material pair and IIRC alluminium is less prone to this.

[bdouvill]

Thanks for all your answers guys!!!
This weekend, I'll check the connection to the engine through the starter (some cleaning/degreasing might be a good idea) and try to connect the LED relay to the battery instead of the frame.

[bdouvill]

Finally, I relocated the LED flasher relay next to the battery and connected it to the battery ground (rather than the frame). I took the opportunity to disconnect the ground line from the starter and degreased the bolt and the cleaned the connector.

Gremlins seem away now and LED flasher relay works like a charm.

Thanks again for your help ;-)