Grounding simplification

Status
Not open for further replies.
acadian

acadian

VIP MEMBER
Joined
Mar 5, 2010
Messages
1,446
Country flag
Hello all, been reading through past threads, and have consulted the OldBritts simplified diagrams... but am still unsure about the simplest approach to take. Right now I'm running a boyer with a single dyna coil set up. The only frame ground point I currently have is the head steady to upper frame (the coil mount ground point was eliminated when I switched to the dyna), the stock wiring harness lead is the only thing terminating at the battery. I'd like to eliminate the head steady ground if possible, and replace with a frame ground from the lower engine mount bolt. Assuming my harness is in good nick, can I rely only on the battery terminal from the harness itself? Or do you suggest I rung a separate ground from the battery to the frame as well? The Old Britts diagram simply indicates a frame ground somewhere off the circuit that terminates at the battery, but no more than that. Any opinions/thoughts appreciated.

:)
 
The issue with the lower engine mount bolt or anything related to engine grounding is that it is isolated from the frame due to the fact that the engine is mounted to the cradle suspended by the rubber isolastics from the frame. Hence the need for so many dedicated grounding points. Do not underestimate the need for these.

What specific function are you trying to ground?
 
pvisseriii said:
The issue with the lower engine mount bolt or anything related to engine grounding is that it is isolated from the frame due to the fact that the engine is mounted to the cradle suspended by the rubber isolastics from the frame. Hence the need for so many dedicated grounding points. Do not underestimate the need for these.

What specific function are you trying to ground?
Click to expand...

Thanks, getting closer. My main objective is to ensure I have the ignition (boyer/dyna) well grounded as I suspect I was suffering from intermittent weak sparking. I have a big honking head ground strap in play right now. Are you suggesting I leave this and add additional engine ground points? Perhaps another from the battery terminal to frame as well?
 
I mentioned in and earlier post that i had no less than 5 grounding point to the frame. One to the timing chest, one to the taillight area, one to the headlight housing, one to the headsteady and one from the battery + to the frame.

There is one more. I have a dedicate wire that goes from the + (with the red wire from the PowerArc unit) side of the coil directly to the + terminal of the battery. Overkill? I don't think so.

To simplify and to bring as much integrity as possible into the system, I have eliminated both blue canned units along with the Lucan Reg/Rec unit, the zener and all associated wiring in favor of the 200watt Podtronics unit and the 16amp stator. My only other strange item is the Napa NF 552LL electronic flasher in favor over the magnetic type.

Other than the switchgear, lighting connection, routing and what-not, this is my electrical system. Simplicty is key to reliability.
Any suggestions you can gather from this is your take or leave.

Peter
 
Hi Acadian

The purpose of grounding the head(and I know you already know this ) is to provide a return path for the current flowing through the Spark plugs. As pvisseriii says, the engine is insulated from the rest of the frame by the isolastic lower mountings, and by the rubber supports in the head steady. The logical place to ground the engine is therefore to the metal connected directly to the spark plug shells i.e. the cylinder head. For once Norton got this right and grounded the right bit! so yes, if you want the best return for the high voltage part of your ignition, leave the Earth strap to the head.

There is only one ground point required for the engine, see above, so you do not need "additional engine ground points".

The frame is used as "ground" for the rest of the electrical circuits, and the thing which is important here is not that you add additional ground connections, but that the ones required are not dirty/corroded etc.

For what it's worth, my opinion is that using the frame as the return is bad practice, and my bike will be rewired throughout using a nice thick wire as the return, alleviating all the angst involved with resistance due to bearings, gaskets, grease, corrosion etc. :)
 
pvisseriii said:
I mentioned in and earlier post that i had no less than 5 grounding point to the frame. One to the timing chest,
Click to expand...

What is the connection to the Timing chest for?

Peter
 
pvisseriii said:
I mentioned in and earlier post that i had no less than 5 grounding point to the frame. One to the timing chest, one to the taillight area, one to the headlight housing, one to the headsteady and one from the battery + to the frame.

There is one more. I have a dedicate wire that goes from the + (with the red wire from the PowerArc unit) side of the coil directly to the + terminal of the battery. Overkill? I don't think so.

To simplify and to bring as much integrity as possible into the system, I have eliminated both blue canned units along with the Lucan Reg/Rec unit, the zener and all associated wiring in favor of the 200watt Podtronics unit and the 16amp stator. My only other strange item is the Napa NF 552LL electronic flasher in favor over the magnetic type.

Any suggestions you can gather from this is your take or leave.

Peter
Click to expand...

Interesting, I've removed the blue can headaches myself, but am curious... are your 5 frame grounds directly terminated at a single or multiple points?

thanks
 
Old Bloke said:
Hi Acadian

The purpose of grounding the head(and I know you already know this ) is to provide a return path for the current flowing through the Spark plugs. As pvisseriii says, the engine is insulated from the rest of the frame by the isolastic lower mountings, and by the rubber supports in the head steady. The logical place to ground the engine is therefore to the metal connected directly to the spark plug shells i.e. the cylinder head. For once Norton got this right and grounded the right bit! so yes, if you want the best return for the high voltage part of your ignition, leave the Earth strap to the head.

There is only one ground point required for the engine, see above, so you do not need "additional engine ground points".

The frame is used as "ground" for the rest of the electrical circuits, and the thing which is important here is not that you add additional ground connections, but that the ones required are not dirty/corroded etc.

For what it's worth, my opinion is that using the frame as the return is bad practice, and my bike will be rewired throughout using a nice thick wire as the return, alleviating all the angst involved with resistance due to bearings, gaskets, grease, corrosion etc. :)
Click to expand...

Thanks for the tips. Right now I've got all the ancillary (non engine) grounds terminating into the sock harness, which in turn terminates at the positive battery terminal. I do not have the battery itself separately grounded to the frame as of yet.
 
I was very careful when I rebuilt my 69 and made sure I had clean grounding points at the wings where the coils mount, the bracket the rectifier is mounted on several around the Z plates, the battery tray to the rear mudguard the headlamp shell. After I had everything together I covered the spots with rustolium. I checked all ground points with my ohmmeter and not finding any significant resistance, I went ahead and wired the rest if it up and haven't had any problems since, no extra ground wires, not even the one for the early bikes, from the engine bottom to the prop stand bolt. That's not to say if you have a bike with old connections it wouldn't be wise to make a few judicious connections from your battery ground to some of these same points. I'm just saying frame grounding can be done.

Dave
69S
 
Old Bloke said:
The purpose of grounding the head(and I know you already know this ) is to provide a return path for the current flowing through the Spark plugs.

if you want the best return for the high voltage part of your ignition, leave the Earth strap to the head.
Click to expand...

For single coils certainly, but Acadian mentioned a single Dyna coil, so presumably a dual ouput coil and dual coils usually have one positive and one negative output, as they are the opposite ends of the secondary winding, therefore it is only necessary for continuity to exist between the plug bodies (i.e. across the cylinder head) to complete the HT circuit, so dual coils do not generally need a return path to the battery.
 
For positive grounded machines, this diagram indicates the need to ground the + terminal. Instead of grounding to frame, I sent a wire back to the + post of the battery. For me the redundancy is worth the meter of wire.

Grounding simplification
 
pvisseriii said:
For positive grounded machines, this diagram indicates the need to ground the + terminal. Instead of grounding to frame, I sent a wire back to the + post of the battery. For me the redundancy is worth the meter of wire.

Grounding simplification
Click to expand...


Ok, so it seems with the dual output dyna coil the head strap ground is unnecessary. Instead I could ensure I have a solid ground from the coil itself back to the battery or ground to the frame at the coil bracket. Additionally, I could ground the battery itself to the frame down near the Z plate?
 
acadian said:
Additionally, I could ground the battery itself to the frame down near the Z plate?
Click to expand...
As long as it is substancial, solid, clean, and pure to the frame, I would say you could put it were ever you like. i think it's best to keep it close to the battery post though.
 
I run a very simple wiring sytem on my Featherbed 850 I only run 5 main wires in the wiring and 1 ground wire but is grounded in 4 diffrent places, tail light, electical tray under the seat, head and front headlight but they are all connected to the one ground wire, I have run this way for 32 years now and have never had any problems at all.

Ashley
 
L.A.B. said:
Old Bloke said:
The purpose of grounding the head(and I know you already know this ) is to provide a return path for the current flowing through the Spark plugs.

if you want the best return for the high voltage part of your ignition, leave the Earth strap to the head.
Click to expand...

For single coils certainly, but Acadian mentioned a single Dyna coil, so presumably a dual ouput coil and dual coils usually have one positive and one negative output, as they are the opposite ends of the secondary winding, therefore it is only necessary for continuity to exist between the plug bodies (i.e. across the cylinder head) to complete the HT circuit, so dual coils do not generally need a return path to the battery.
Click to expand...

I stand corrected :) I must stop living in the past.
 
Exactly what I've done, collected all the major circuit grounds to one point and ran a heavy gauge-fused line back to the positive battery post.

Nothing's blowed up so far...
 
Status
Not open for further replies.

Similar threads

C
Starter Motor - Positive to Negative Ground
Replies
4
Views
189
Cheesehead Commando
C
WEM
  • Locked
Grounding front indicators
Replies
4
Views
547
possm
possm
maaseyracer
Negative Ground for a Single Device
Replies
15
Views
693
dave M
D
jimbo
  • Locked
boyer pick up plate rubbing/ grounding out on engine case?
Replies
2
Views
559
jimbo
jimbo
S
  • Locked
Headlight ground
Replies
9
Views
1,022
sadolfsonmark3
S
Back
Top