Bizarre electrical problem

Earlier this year I bought a 2001 ST1100 ABS/CBS/TCS in Candy Graceful Red with 45,000 on the clock. It's my first Honda since a beautiful black CB500 four when I was a teenager a long time ago. I guess I bought the Pan because it's become something of a legend and I was curious to see how I would get on with it. I've owned and worked on many bikes, but over the years various generations of BMW boxer have been a dominant theme. I've liked them for a simple reason. I have a kind of "formula" that seems to determine how I get on with a bike. It's the pleasure gained from riding it, divided by the effort required to keep it in the great shape I like my bikes to be in. Because of their simplicity, the oil head boxers do rather well being fun to ride whilst being simple and easy to maintain ( no water cooling, easy access to pots, injectors etc.) So how is the Pan faring by comparison? Well it is certainly fun to ride, with a gloriously smooth and responsive engine, but oh boy it's hard to work on!
So after what feels like many many hours of work I've pretty much sorted everything. New swing arm, steering head bearings, re-built forks, brake overhaul, new cush rubbers, new tyres etc. Just got to the point when I thought I could start to focus on riding it when along comes this horrible electrical fault, and I'm hoping somebody can point me in the right direction.
It has now happened twice that the bike has suddenly gone into a state when it goes crazy when indicating right. The engine stutters and loses power, and the Main beam, TCS, TCS active, and TCS off lights start flashing. If the engine is idling, and you indicate right, the engine stops and the listed indicator light flash. I've taken a video of the flashing sequence and and slowed it down and you can see that the main beam indicator is flashing weakly in synchrony with the right hand indicator, and then the TCS light follows a fraction of a second later, followed by the TCS active and TCS off lamps together. The net result is that the main beam indicator flashes in synch with the indicator, whilst the other TCS related indicators flash out of synch with it. The bike is just about rideable but you have to go slowly, and not use the right hand indicator. While experimenting I also found that the horn does not work when in this state, and again kills the idle if you touch the switch.
Yesterday I pulled off all the plastic and had a good look at the whole loom, plus dismantled, cleaned and re-assembled all the connectors just behind the steering head. None of them were in a bad state. Whilst they were disconnected I found that if I made the right turn indicator connection on the main harness plug with the left hand handlebar switch disconnected, the problem still occurred ruling out any issues with the left hand handlebar switch. So now to the most frustrating bit. Having fiddled, cleaned and inspected as much of the electrics as I could, but failing to find any "smoking gun", the problem suddenly went away. The horn and RH indicator work perfectly! I'm left not knowing what the problem is, and not trusting the bike to transport me anywhere reliably. Are there any electrical geniuses out there who could give me a pointer where to look now? A fault as dramatic as this must have a visible findable cause somewhere. Any ideas?

My first guess on such an issue would be a faulty ground connection. Did you remove the ground terminals at the attachment points on the frame, clean the bits and the terminals? Before you button up the bike, use a good contact cleaner to clean all the connector bodies inside, allow to dry, then insert dialectic grease into the connectors to help protect them from moisture. If you do this to every connector on the bike, your electrical issues should be minimal.
Be sure to clean both battery terminals, the main power terminal connections at the main fuse. Sometimes these can appear clean but have an oxidized layer between them that will cause poor charging and discharging of the battery. Low current capabilities can also cause the electronics to go wonky.

Good luck... and let us know what you find!

Also give some attention to the mains connectors hidden behind the steering head (remove air-filter housing for access)

Hi Vinny, Thanks for the tip. I've figured from the characteristics that it must be an earthing issue. Can you point out where the earthing points are? I'm not sure where I need to go and look. I've taken care of the main loom connectors behind the steering head, but not sure exactly where to find the various earthing points. Determined not to let this beat me!

Well, I would have to drag the ST out of it's cave... There are probably several and most likely easier to find when the tupperware is removed from the bike. Off the top of my head I am not certain about the locations. Someone intimately familiar with electrical issues may be a bit more help with the locations. Treating the electrical connectors and cleaning the grounds was something I did during the 90,000 mile service about two years ago... my short term memory is limited to less than two minutes... seriously. Wish I could be more help.

Connector on the starter relay?

A little bit right of your left heel when you're driving your ST1100.

There's a ground point on the frame just behind the centerstand lift assist handle. Remove the bolt and insure bare metal on the frame, any corrosion removed, reinstall. HTH

And yes, check the red 4P main fuse/starter relay connector as shown above.

The engine ground cable leads from the battery (-) post to a spot just below the tip-over bar and to the rear of the starter motor cable. Schematic on page 1-28 (standard model) in my Honda Service Manual.

John

For the ABS models there appears to be a ground by the ABS indicators the Motor driver box and near the ABS control unit. Most of that is tucked away in the front part of the fairing on either side of the headlight. I'm experiencing a faulty ground in that area on my 97ABS. My ABS light flickers a bit before it goes out and it isn't an error code type of flicker. I too have to clean and inspect all my connectors
Oh ...and check your main positive lead just above the left footpeg just under where the shelter bolts on...I discovered my red lead had something rubbing and scraped of the insulation and it could short out at the frame. (that was a bizzare thing and I stumbled across it quite by accident.

I don't remember my symptoms, but I found the negative side of the battery was loose. Tightened it up and that took care of it. Hope yours is juST as simple and easily found.

John STeele
Peace and All Good

Sounds like something that happened to my son on his Yamaha FZ6. Fixed the problem when the ground on battery was cleaned up and reconnected with the battery nut not being cross-threaded.

Check everything that was mentioned above - Grounds, battery connections, starter solenoid connector, connector behind the steering head.

Occasionally there is a high resistance in the ignition switch. And it's a good idea to do the "red wire bypass" mod. - that reduces current through the ignition switch.

Download John O.'s colored coded schematic.

Thanks to all for your sage advice. I took off the sidepanels, top shelter, and air cleaner box and inspected every inch of the loom I could see, but did not find any visible problems at all. The much mentioned red starter solenoid connector connector is perfect. I tightened the battery terminals, although they were actually tight and clean already. I then disconnected all the connectors just behind the steering head, and removed the earth that bolts just to their left. I replaced the eye/ring connector on the ground wire with a new one that I soldered on, and re-bolted having cleaned the metal with emery paper. I then sprayed Comma contact cleaner onto all the connectors, male and female, scraped the spades with a small screwdriver, and left them to dry. Finally I reassembled with the connectors with silicone grease. I did not get to any other ground connections and loom connectors either around the headlamp or the starter moter, etc. as I did not have the time to remove all the other plastic. After all this effort, and no real "smoking gun" root cause found, the problem seems to have gone away, and I swear that all the indicator lights etc. on the dashboard look brighter although this may well be wishful thinking. Because I did not find an obvious cause, I'm still rather mistrustful that the problem will re-appear just when I am using the bike to get to an important appointment, but I'm crossing my fingers that I might have banished it. This weekend I will look for the ground behind the pull out handle as suggested in an earlier posting, and clean that up, but after that I want to go ride . Thanks again for all the great suggestions.
Next job when I have mustered the courage - replace the shabby centre stand with the nicely blasted and powder coated version I bought off Ebay, plus fit the shiny new exhaust silencer to downpipe gaskets I just bought from David Silver to replace the very mangled ones on there now which make silencer replacement an ugly process. I already know that to replace the centre stand and remove without fouling the downpipe collector box, I will have to remove the rear wheel, so first task will be to work out how to support the bike safely during the operation. But that's for a new thread.

Nicksquid said:

Next job when I have mustered the courage - replace the shabby centre stand

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Not sure about what you need to do on an 1100, but for my 1300, I pulled the mufflers and the right side header pipe. Then I was able to remove the axle for the center stand out the right side. The bike stayed upright on the front and rear wheels using the side stand. I had the header crush washer on hand, and had read warnings here about over tightening and snapping the studs that hold the header to the block. When I reassembled it, I greased the axle and pivot points which no doubt lasted until it washed off in the first rain I encountered.

Nicksquid said:

Because I did not find an obvious cause, I'm still rather mistrustful that the problem will re-appear just when I am using the bike to get to an important appointment...

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Next time you get around remove left pannier, seat and left side panel, then peek under the base of the fold-out handle, you'll spot another mains ground connector there, which might be in need of attention.
While at it un-clip the fuse box/es, flip them around and inspect the crimps on the backside; also on the inside some protective spray will help, as well as removing and re-inserting every single fuse can help to scrape oxidation off the prongs...

Hi Nick, forgive me for saying but was the bike in a bad state when you bought it, as you seem to have done a fair bit of work to it.
Cheers
Chris

So I can finally finish the story. I'm on my way home from the take away with dinner late one evening in the dark and wham, the fault suddenly occurs when I indicate right. The engine loses power, and the whole plot turns into something of a nightmare to ride. I nurse the bike back home, and once back in my driveway, find that the problem has now decided to be permanent, which makes diagnosing much easier. It is definitely associated with the RH indicator, so I try removing the RH bulb. The problem disappears. So then I put the bulb back in and use a piece of wire to ground it to the RH mirror mount. The problem disappears. So I have a faulty earth associated with the RH indicator circuit. As I did not feel up to removing the countless items of plastic required to access the wiring behind the headlamp, I got the soldering iron out and modified the RH indicator cable to earth to a tag bolted under one of the mirror mount bolts. Since then the problem has not re-appeared. So kiltman, you were spot on I think with your suggestion re: the earth somewhere near the headlamp. When the problem occurred the ABS units would also get triggered, so one day I may summon up the courage to go in there, but for the moment my auxiliary earth seems to be doing fine. Thanks to all of you for your advice - much appreciated. Now to find out where that slight smell of coolant is coming from when the bike is hot

Hi Chris, Actually the bike was in pretty good condition, but it is 15 years old, and some things like the notchy original steering head bearings made the handling pretty bad. I'll admit that I am fussy, and not happy until I know every inch of a bike is in good shape, so I've now done quite a lot of work on it. Next on the list are new front brake pads, as they are getting pretty thin, fitting the nicely refurbished centre stand that I bought on Ebay to replace the existing one that has some rust issues (not an easy task I've realised as the exhaust manifold stops you removing the centre stand unless you remove the rear wheel), doing the tappets, and replacing the 15 year old cambelt (only done 43k though so hopefully in good shape), although apart from the brake pads, I'm not in a hurry to do any of these tasks. Compared to the many BMW airheads and oilheads I've had over the years, the Pan is a complex beast. I could do the tappets on my R1100 and 1200RT in about 20 mins. I've not had the courage to check them on the Pan yet. Still, I'm slowly developing more respect for the bike now that I've banished the electrical problem, and got over the embarrassment of dropping it twice at walking pace before I'd got used to the ultra low speed handling and the sheer weight. The second drop when turning on an incline cost around ?200 for a new mirror, glass and plastic, plus a new crash bar cover and the annoyance of a handful of scratches on the previously perfect RH pannier lid. I'd never dropped a bike like this in my life before, so my initial reaction was to get rid of it, but I've got over that now.

Nicksquid said:

So I can finally finish the story. I'm on my way home from the take away with dinner late one evening in the dark and wham, the fault suddenly occurs when I indicate right. The engine loses power, and the whole plot turns into something of a nightmare to ride. I nurse the bike back home, and once back in my driveway, find that the problem has now decided to be permanent, which makes diagnosing much easier. It is definitely associated with the RH indicator, so I try removing the RH bulb. The problem disappears. So then I put the bulb back in and use a piece of wire to ground it to the RH mirror mount. The problem disappears. So I have a faulty earth associated with the RH indicator circuit. As I did not feel up to removing the countless items of plastic required to access the wiring behind the headlamp, I got the soldering iron out and modified the RH indicator cable to earth to a tag bolted under one of the mirror mount bolts. Since then the problem has not re-appeared. So kiltman, you were spot on I think with your suggestion re: the earth somewhere near the headlamp. When the problem occurred the ABS units would also get triggered, so one day I may summon up the courage to go in there, but for the moment my auxiliary earth seems to be doing fine. Thanks to all of you for your advice - much appreciated. Now to find out where that slight smell of coolant is coming from when the bike is hot

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Good to hear you resolved that first issue. Smell coolant while running?........not a good thing. My bet is the O-rings on the two coolant elbows, which is one at top, upper center of each head........common issue if they've never been replaced. Also, with elbows off, look for fracures in each aluminium housing........another common issue, specially with left side elbow. Been there, done that associated with both coolant elbows. Just mentioned, as this IS where you'll be head next for the repair(Tupperware removal,fuel tank removal, then carb bank removal in order to access area).

Brant said:

Good to hear you resolved that first issue. Smell coolant while running?........not a good thing. My bet is the O-rings on the two coolant elbows, which is one at top, upper center of each head........common issue if they've never been replaced. Also, with elbows off, look for fracures in each aluminium housing........another common issue, specially with left side elbow. Been there, done that associated with both coolant elbows. Just mentioned, as this IS where you'll be head next for the repair(Tupperware removal,fuel tank removal, then carb bank removal in order to access area).

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Not necessarily the problem here, although on these older bikes these things should be attended to to prevent a hose, or elbow, blowout on the road. It could also be something as simple as the common cracked overflow hose at the thermostat housing.