engine grounding

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Dick Sherbocker

New Member
#1
#1
Just finished putting my refurbished Honda QA50 back together. Upon trying to start I could tell I was getting no spark. I stripped and painted the frame, however on re-assembling I failed to scrape some paint off the engine mounting area. I'm wondering if I would run a wire from one of the engine bolts to a bare spot on the frame (under the coil) if this would ground the engine? I have resistance everywhere but the spark plug cap. When I remove the plug, ground it against the engine no spark.
Any ideas?
 
sparkwizard

sparkwizard

#2
#2
The idea is to ground everything TO the engine. Clean the spots where the coil mounts to bare metal.
Where the engine slide up into the frame, it should contact bare metal. If you have lights, they should also mount to bare metal.
I hope this helps. Let us know, please.

Yes, you could run an external wire if you don't want to drop the engine again.
 
Mr. Pink

Mr. Pink

Well-Known Member
#3
#3
I'm thinking that even if the engine is electrically isolated from the frame (paint).
There should still should be spark and just the kill switch would not function.

1707355630257.png
 
sparkwizard

sparkwizard

#4
#4
Mr. Pink said:
I'm thinking that even if the engine is electrically isolated from the frame (paint).
There should still should be spark and just the kill switch would not function.

View attachment 311148
Click to expand...
If that ground symbol below the flywheel does not connect (through the frame) to the ground symbol near the coil, no spark.
I simple 12 Ga ground wire from the carb mounting bolt to the coil mount would provide enough ground for spark, though.
 
Mr. Pink

Mr. Pink

Well-Known Member
#5
#5
sparkwizard said:
If that ground symbol below the flywheel does not connect (through the frame) to the ground symbol near the coil, no spark.
I simple 12 Ga ground wire from the carb mounting bolt to the coil mount would provide enough ground for spark, though.
Click to expand...
Yes, I was making the assumption that the condenser is grounded to engine case through its mounting bracket.
I also made the assumption that the other grounding point at the flywheel also was in contact with the engine case.

Either way, an auxiliary grounding wire will do the trick.
 
sparkwizard

sparkwizard

#6
#6
On that bike, the coil is mounted above the engine, under the fuel tank. The carb is an a short manifold mounted above the horizontal cylinder.
A wire, about 6 inches long, from the carb-to-manifold bolt, to the coil should be almost invisible. That should be all the ground needed for spark.

(Condenser is mounted on the coil, under gas tank.)
( Assuming handlebars are not painted, kill switch should also work.)
 
Last edited:
D

Dick Sherbocker

New Member
#7
#7
sparkwizard said:
The idea is to ground everything TO the engine. Clean the spots where the coil mounts to bare metal.
Where the engine slide up into the frame, it should contact bare metal. If you have lights, they should also mount to bare metal.
I hope this helps. Let us know, please.

Yes, you could run an external wire if you don't want to drop the engine again.
Click to expand...
Dropped engine and cleaned four engine mounting points. Cleaned coil mounting points, still no spark. Checked resistance at the coil and points wire both show 2.5 ohms however spark plug wire shows nothing. Shouldn't I see some resistance at the end of the spark plug wire?
 
D

Dick Sherbocker

New Member
#8
#8
Dropped engine and cleaned four engine mounting points. Cleaned coil mounting points, still no spark. Checked resistance at the coil and points wire both show 2.5 ohms however spark plug wire shows nothing. Shouldn't I see some resistance at the end of the spark plug wire?
 
D

Dick Sherbocker

New Member
#9
#9
Mr. Pink said:
Yes, I was making the assumption that the condenser is grounded to engine case through its mounting bracket.
I also made the assumption that the other grounding point at the flywheel also was in contact with the engine case.

Either way, an auxiliary grounding wire will do the trick.
Click to expand...
Dropped engine and cleaned four engine mounting points. Cleaned coil mounting points, still no spark. Checked resistance at the coil and points wire both show 2.5 ohms however spark plug wire shows nothing. Shouldn't I see some resistance at the end of the spark plug wire?
 
ole4

ole4

#11
#11
That is a energy transfer ignition. ( AC ignition) It is critical that the flywheel is located correctly usually a peg or keyway. The points have to open when the AC sine wave is at or near its peak. Did you time the points open point correctly? What is the procedure for setting the points. I had BSA hornets with that system and it worked great only if it was timed correctly.
 
sparkwizard

sparkwizard

#12
#12
Also, when you painted it, did you get paint up inside the frame, where the engine slides in? Did you scrape the paint off the inside of the frame where the engine makes contact? That would be at the inside of the four bolt holes.
 
D

Dick Sherbocker

New Member
#15
#15
ole4 said:
That is a energy transfer ignition. ( AC ignition) It is critical that the flywheel is located correctly usually a peg or keyway. The points have to open when the AC sine wave is at or near its peak. Did you time the points open point correctly? What is the procedure for setting the points. I had BSA hornets with that system and it worked great only if it was timed correctly.
Click to expand...
I followed the manual for timing, points set at .012, light came on at the F mark.
 
sparkwizard

sparkwizard

#19
#19
Dick Sherbocker said:
Shouldn't I have some resistance at the end of the plug wire? I have none there but 2.5 ohm at the coil and points wire.
Click to expand...
No resistance would read 0 on an ohmmeter, same as touching the red and black leads together.
Do you mean no continuity? same as not touching anything with the leads?
Plug wire should have high resistance, high numbers.
 
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