Update - My wiring harness got very melty...

[RPC3]

Update - please jump to the bottom of this thread, issue is electrical


Hi Guys,

Need some help troubleshooting when I get home tonight. Took my bike to work (about 8 miles, a few lights) and roughly 5 miles in I had a few...I don't want to call them surges, but bogs or dead spots that made it seem like I was hitting bumps in the road (which was my initial reaction, guessing it was due the engine bogging and my momentum surging forward a bit as the engine would kick in/out). This kept up on steady throttle for about a quarter mile (on and off) so I pulled over to check everything out.

I didn't see any hoses that came disconnected, carbs were still seated, checked numerous bolts and some wiring connections and everything looked normal. Went to start the bike up and the e-start wouldn't work (push button, no response/sound/just a dead button). This could be unrelated, but its worked perfectly as long as I've owned the bike until now, so worth mentioning.

Was able to kick start the bike and made it the rest of the way to work with the only real noticeable off characteristics being a slightly high idle and perhaps a lack of power/smoothness under full throttle, but it cruised at a maintained speed fine.

So assuming I can make it home okay later, I'm curious to know where you would start the trouble shooting process. I'll check out the soldering/connection on the e-start to see if that can be ruled out as a simple wiring issue.

Bike is 78 standard, stock engine/electrics. Only thing I changed recently was the tail light bulb (1157, previous bulb had a filament burn out). I don't have fuel filters on the bike, tank is pretty clean, but initial thought was maybe a blockage in one of my carbs that was causing some fuel starvation intermittently to one cylinder. I've never checked my rotor/charging system because its always just worked, but if there are signs of a charging issue I could check that. I've never messed with the carbs, but I did set cam chain tension and valve height per manual about 500 miles ago and its been fine since, but I didn't touch the points so the timing/points could be in need of servicing.

Just looking for ideas, who knows – the ride home might tell me all I need to know.

 

[DogBunny]

I'm curious to know where you would start the trouble shooting process.

I don't have fuel filters on the bike, tank is pretty clean, but initial thought was maybe a blockage in one of my carbs that was causing some fuel starvation intermittently to one cylinder.

First thing I'd do is look at plug condition for fouling.
There is no excuse for not having a fuel filter. Second thing I would do is check for partially plugged jets or carb passages due to no fuel filter.
Then I would check for bad electrical connections.

 

[NONclow]

I don't have fuel filters on the bike, tank is pretty clean, but initial thought was maybe a blockage in one of my carbs that was causing some fuel starvation intermittently to one cylinder.

Get some filters!

I've never messed with the carbs

http://www.xs650.com/forum/showthread.php?t=3

 

[RPC3]

yeah yeah I know...bad on my part. I actually bought them and new fuel line a month back but just never got around to installing them (guess it might be time...).

I've completely torn apart and rebuilt carbs on a Honda CL200, so just reading through the guide it seems pretty sensicle and well laid out. I've actually got full rebuild kits ready to use, but was hoping to ride for the summer/fall and then rebuild multiple parts over the winter.

I'm not too nervous about the carbs if those are the issue, electrics are what scare me more - so glad to hear no one thinks its a potential electrical issue (so far).

 

[5twins]

Well, I might, lol. The first thing I would check is to see if the bike is still charging. These bikes need a near fully charged battery to run right. The ignition depends on it to function correctly. If the charging stops, the bike will run OK for a little while until the battery charge drops. Then it will run worse and worse the lower the battery gets, eventually dieing. The non-functioning e-start could be a sign of a low battery as well.

Do the simple charging test - start the bike and clip a volt meter to the battery terminals. You should see around 12 volts at idle. Rev it up to 2500 to 3K and the voltage should climb to near 14.

If you are charging, it's also possible the battery is dieing and won't hold that charge.

 

[RPC3]

About to head home. Looks like some stuff is getting melt, can't say I'm thrilled by the prospect of what that means. Also, silver item being pointed to (regulator?) is hot to the touch even though bike has been sitting with a side covet for 8 hours... Must be drawing a current, right?

 

[RPC3]

duplicate post

 

[RPC3]

Charging system it is.... Can make it until I need to idle, then the bike dies out. Good call 5twins. Should mention that the battery was new as of June, for what it's worth.

 

[RPC3]

Alright - got myself home (flatbed tow truck was friendly). Had a chance to dig into the wiring a bit and there's an obvious issue; the 5 pin connector that is 3 whites, 1 red, 1 (burned to a crisp...black at one point?) plug that connects to the 5 pin plug that mounts under the battery box; that one had a mishap.

Like I mentioned, the regulator was very warm to the touch when I got back to the bike to leave work; felt like it was drawing current. I followed the toasted wire up to my frame and wanted to get some advice before following it further; I was hoping I'd be able to just splice in some clean wire to replace it, replace the plug, and re-mount everything (after getting an upgraded reg/rec put in), but the further I go the more I fear this wire has melted its insulation throughout the whole harness, wherever that may lead.

Where should I even start with this? Keep following the wire that has melted (Created quite the mess...). Well, good news is there's no more bogging. Doesn't seem like there will be much of anything for the next week or two. If there's anything I can do to help you guys help me trouble shoot (pictures, tests with a multimeter, etc) please let me know, I'm a bit blind to electrical issues at the moment.

 

[650Skull]

Buy as new harness that one is shot.

Check out the electrical threads in the tech menu. Everything you need to know and how to's and explanations.

Do "Google search", (top left), questions for different parts replacements, like regulator or rectifier.

Lots of money can be saved going alternative/aftermarket

 

[tonyc]

I built my own harness and soldered ever joint. Has been working for fine for three years.

 

[RPC3]

okay; sounding like new harness might be for the best anyway. Trying to get my ducks in a row on purchases here.

1) new wiring harness, be it from mikesxs or elsewhere. I'd like to keep stock set up as much as possible for now.

2) VR-115 regulator off ebay; splice in or mimic stock regulator connector to attachment to wiring harness

3) 2 or 3 bridge solid state rectifier with heat sink, again splicing in or mimicking stock connector to attach to wiring harness

Anything else while I'm at it? I'm going to have the bike torn down pretty well, so I plan on cleaning and greasing connections as I put them together, but would like to address anything else that dovetails with this type of switch while I'm in there.

 

[XSLeo]

The thing you pointed at in the one pic is not the regulator. That is the safety relay. The regulator is on the other side. It has a green tube down one edge. The rectifier is on the bottom of the battery box.
I'll post pics.
Leo

 

[RPC3]

Thanks Leo - that means that where my rectifier plugged into the main harness is where my trouble visually manifested and worked its way up the harness. Should I be paying any attention to the safety relay during this process?

 

[XSLeo]

The safety relay as on your bike is just to shut off the power to the starter relay so the starter won't run when the engine starts.
The way it works is when you turn on the key power flows through the relay to the starter relay. You push the start button to start the bike. Now as the engine starts the alternator starts to charge, Some of this charge is sent out from the alternator on the yellow wire. When the voltage on the yellow wire reaches about 4.5 volts it trips the safety relay, this shuts off the power to the starter relay. It stays tripped until you shut off the engine. This way it protects not so much the starter but the gears that engage the crank.
On the replacement reg and rec, cut the wires off the old stock units as close to the units as you can. Now use these wires and plugs to hook to the new parts, this make it plug and play.
On my first XS650, a 75 I got while I was In the service, shorted the ground on the turn signal flasher and burnt up most of the harness. The same thing happened on the 75 I have now. A PO replaced the ground with a new wire before it toasted the harness. I rewired it my self and got rid of most of the extra crap the factory put in. I have just the basics, head/tail light, turns and a horn. No RLU, no light checker none of that crap.
If you get the harness from Mike's they often have some of the plugs wired wrong. Not a problem, when you plug something together make sure the colors match across the plug. They often have them in the plug wrong. Easy to swap around to match. Change the wires on the harness side. This makes parts replacement easier.
Leo

 

[RPC3]

Found a likely culprit... Or contributor anyway. Think my coil is toast too wire seems kind of integral to the unit...

 

[XSLeo]

That's the harness ground. Your coil looks fine. The plug wire will come off. see the ribbed cap where the wire enters the coil. It unscrews. There is a rubber compression ring around the plug wire that gets squeezed around the wire to seal it in the coil.
Unscrew the cap then the wire unscrews from the coil.
Leo

 

[weaselbeak]

If you are cooking that little ground wire, I suspect the bike is searching for ground wherever it can find it, because your grounding system is not good. Clean up all grounds, and maybe add a good new ground from battery to chassis and R/R.

 

[RPC3]

This look okay for a rectifier?

http://www.ebay.com/itm/35-AMP-3-TH...134?pt=LH_DefaultDomain_0&hash=item3cd786df16

 

[retiredgentleman]

This look okay for a rectifier?

http://www.ebay.com/itm/35-AMP-3-TH...134?pt=LH_DefaultDomain_0&hash=item3cd786df16

Yes, that will work just fine, but all you really need is one rated at 25 amps. There are similar 25 amp units available.