Strange charging problem after coil relay mod

[Skinner]

As per my earlier post I did the coil relay mod to my 1981 GS650GL last weekend. I took it out for a ride Sunday and it ran great, an obvious improvement. That said, it was still running a tad rich so I made some carb adjustments tonight. I also changed the grounding point of my coil relay from direct to the battery to a common grounding point on the frame. The same point that the battery is grounded to in fact.

I went for a ride tonight and the bike ran great. I stopped for gas and that's when I noticed the problem. When I pressed the starter button the starter motor barely ticked over, just enough for the engine to fire up. So I rode directly home, parked in the garage, killed the motor and immediately tried to start it. There wasn't enough power in the battery to turn the starter. I never had any charging problems before the coil relay mod. I installed a SH775 in 2014 and the bike had no electrical issues at all until tonight.

Here's how I did the coil relay mod:

• I disconnected orange/white from both coils and extended them both, then joined them to make 1 wire. Connected this to the relay as my switched 12 volt source.
• I ran 2 wires from the 87 pins back to the coils.
• I connected a ground wire from the relay to the battery at first, and now to a ground point.
• I ran a wire directly from the battery to the relay with a 10 amp inline fuse.

The relay is working because I can hear and feel the click when I turn on the ignition. I get great voltage at the coils and the bike runs noticeably better. But now I have what appears to be a charging issue. I didn't have time to attempt a diagnosis tonight. Any ideas what could cause this? Could it be my grounding point? Any help is appreciated as always.

Cheers!
K

[posplayr]

As per my earlier post I did the coil relay mod to my 1981 GS650GL last weekend. I took it out for a ride Sunday and it ran great, an obvious improvement. That said, it was still running a tad rich so I made some carb adjustments tonight. I also changed the grounding point of my coil relay from direct to the battery to a common grounding point on the frame. The same point that the battery is grounded to in fact.

I went for a ride tonight and the bike ran great. I stopped for gas and that's when I noticed the problem. When I pressed the starter button the starter motor barely ticked over, just enough for the engine to fire up. So I rode directly home, parked in the garage, killed the motor and immediately tried to start it. There wasn't enough power in the battery to turn the starter. I never had any charging problems before the coil relay mod. I installed a SH775 in 2014 and the bike had no electrical issues at all until tonight.

Here's how I did the coil relay mod:

• I disconnected orange/white from both coils and extended them both, then joined them to make 1 wire. Connected this to the relay as my switched 12 volt source.
• I ran 2 wires from the 87 pins back to the coils.
• I connected a ground wire from the relay to the battery at first, and now to a ground point.
• I ran a wire directly from the battery to the relay with a 10 amp inline fuse.

The relay is working because I can hear and feel the click when I turn on the ignition. I get great voltage at the coils and the bike runs noticeably better. But now I have what appears to be a charging issue. I didn't have time to attempt a diagnosis tonight. Any ideas what could cause this? Could it be my grounding point? Any help is appreciated as always.

Cheers!
K

What makes you think that is a charging problem especially since you did not put any voltmeter to the battery?

[Skinner]

I just assumed it was because the battery didn't have enough power to turn the starter motor. I should add that I put the battery on charge for 10 minutes and the bike started normally. I'll put a voltmeter to the battery in the next day or two.

If if not a charging problem then what are some other possibilities?

[bonanzadave]

Double check all battery connections and possibly a missed wire.

[posplayr]

I just assumed it was because the battery didn't have enough power to turn the starter motor. I should add that I put the battery on charge for 10 minutes and the bike started normally. I'll put a voltmeter to the battery in the next day or two.

If if not a charging problem then what are some other possibilities?

Then do the Quick Tests and confirm it is not charging before guessing anymore.

[Skinner]

posplayr

Then do the Quick Tests and confirm it is not charging before guessing anymore.

I did the Quick Tests tonight (results later in this post) but not before checking my grounding points. I read all of your posts regarding charging, SPG and grounding (excellent and very informative BTW) and thought I should clean that up before proceeding with the tests. What I found was quite interesting. Typically the stock R/R is mounted to a rubberized plate which is in turn connected to the frame. Grounding the R/R to one of its mounting bolts is one of the things you suggest, and it makes sense. However, on my 1981 GS650GL the R/R mounting plate is not rubberized nor does it have any metal to metal connection to the frame; it is bolted to a couple of metal angles which are in turn fastened directly to the plastic air box. The air box assembly supports the plate which in turn supports the R/R and igniter. There is no metal frame connection at all. So connecting the R/R to this plate wouldn't ground anything at all. The only convenient grounding point seemed to be at the dreaded battery box, but I didn't want to use this as a SPG point because there would not be adequate space. So I ran a ground wire from the R/R mounting plate to a bolt near the fuse panel (which sits directly under the seat). This is connected directly to the frame. I then used the R/R mounting bolt as a SPG point. I connected the R/R ground wire to this bolt and ran another ground from here directly to the battery. I also grounded my coil relay mod to this point. This is not an ideal situation but there as really no other point for me to connect to a frame grounding point, at least not that I could find. Before I fastened my ground wires I used my Dremel to clean any paint and corrosion at the ground points and coated the bare metal with dielectric grease. The bike started up just fine so I proceeded to do the Quick Test:

- key off - 12.34 volts
- key on, headlight on low beam - 11.60 volts
- 1500 rpm - 14.01 volts
- 2500 rpm - 14.10 volts
- 5000 rpm - 14.25 volts
- key off - 12.88 volts

My R/R is a SH775. My take on these numbers is that my battery isn't up to snuff, but it is taking a charge.

Your thoughts on all of this? Thank you again for your excellent posts - they helped the grounding situation make sense to me.

Cheers!
K

[posplayr]

posplayr


I did the Quick Tests tonight (results later in this post) but not before checking my grounding points. I read all of your posts regarding charging, SPG and grounding (excellent and very informative BTW) and thought I should clean that up before proceeding with the tests. What I found was quite interesting. Typically the stock R/R is mounted to a rubberized plate which is in turn connected to the frame. Grounding the R/R to one of its mounting bolts is one of the things you suggest, and it makes sense. However, on my 1981 GS650GL the R/R mounting plate is not rubberized nor does it have any metal to metal connection to the frame; it is bolted to a couple of metal angles which are in turn fastened directly to the plastic air box. The air box assembly supports the plate which in turn supports the R/R and igniter. There is no metal frame connection at all. So connecting the R/R to this plate wouldn't ground anything at all. The only convenient grounding point seemed to be at the dreaded battery box, but I didn't want to use this as a SPG point because there would not be adequate space. So I ran a ground wire from the R/R mounting plate to a bolt near the fuse panel (which sits directly under the seat). This is connected directly to the frame. I then used the R/R mounting bolt as a SPG point. I connected the R/R ground wire to this bolt and ran another ground from here directly to the battery. I also grounded my coil relay mod to this point. This is not an ideal situation but there as really no other point for me to connect to a frame grounding point, at least not that I could find. Before I fastened my ground wires I used my Dremel to clean any paint and corrosion at the ground points and coated the bare metal with dielectric grease. The bike started up just fine so I proceeded to do the Quick Test:

- key off - 12.34 volts
- key on, headlight on low beam - 11.60 volts
- 1500 rpm - 14.01 volts
- 2500 rpm - 14.10 volts
- 5000 rpm - 14.25 volts
- key off - 12.88 volts

My R/R is a SH775. My take on these numbers is that my battery isn't up to snuff, but it is taking a charge.

Your thoughts on all of this? Thank you again for your excellent posts - they helped the grounding situation make sense to me.

Cheers!
K

Yes it seems that your numbers are a little low and it is probably only due to the low state of charge of the battery. However the only improvement will likely be gaining 14.25 at 2500 RPM.

Note the SPG is a current collection point and not necessarily a place to locate a frame ground. All currents have to come to R/R(-), and while you could just create a big solder ball of connections right at the outside of the R/R(flapping in the breeze), putting a stack or ringlugs together at a single point like a mounting bolt is cleaner. In fact the SPG could be floating but having it attached to some metal helps reduce any heat and in if the solenoid is on the side plate it picks up the solenoid ground so you can energize it.

Again, this is probably part of the confusion of using an overloaded term like SPG. People get the idea that the R/R mounting bolt is like a mounting stud on the frame. It is not. Neither is the case of the R/R in general there any need to ground it other than to help with heat dissipation. So the SPG bolt is primarily just to hold the wires together that allow all of the current to flow from there into the R/R(-).

Remember the SPG strategy is to minimize connections and keep it as clean as possible so there are a minimum number of surfaces to be concerned (e.g. have to maintain) about that might affect voltage drops between the R/R and the battery.

So if you mount the R/R to a piece of plastic and that plastic obviously does not need to be grounded and there is a convenient frame location close by then move the SPG to there and avoid one of the SPG wires. I personally do not like to tighten down a bolt into plastic because it will probably crush the plastic and cause it to loosen. With less pressure on the electrical bonding surfaces, corrosion and dirt is more likely.

Glad to hear that you were able to follow the descriptions.

EDIT: I re read your description and think you did it right. The R/R mounting bolt just hold the wires together so teh jump off to R/R(-) is short. The wires are :

1. R/R(-)
2. Battery(-)
3. B/W from harness
4. and the one you were concerned about Frame ground.

This is what I mean by current collection.

[Skinner]

EDIT: I re read your description and think you did it right. The R/R mounting bolt just hold the wires together so teh jump off to R/R(-) is short. The wires are :

1. R/R(-)
2. Battery(-)
3. B/W from harness
4. and the one you were concerned about Frame ground.

This is what I mean by current collection.

Yes, this is what I did. Thanks again for your help.

Cheers!
K