[soulforge]

Hullo friends,

I am having a real headache that needs support from you guys.
I have with me a Royal Enfield cast iron Bullet 500 ES model that is being changed to be a KS model.
I bought the main wire harness from HMC but it differed slightly with the wire diagram I had(Attached) thus I had to remake the wire harness to match the diagram.
Everything seems to be in order such as horn, trafficators, lights except that the spark plug would not spark.
I checked the CB point and noticed that the ammeter needle does not move when the point opens and closes.
I adjusted the gap and changed the condensor just in case but still nothing.

I set the egg shape shaft to be at its most far from centre at TDC and adjusted the gap to be 0.4mm.

Currently when key on, the ammeter needle slightly moves to (-).
I believe the needle should go to the middle when I rotate the contact breaker plate which opens and closes the points but nothing happens.
Now I am starting to think that mayhap the harness is the problem but after double checking am exhausted and clueless.

Does anybody have an opinion or something that I have missed or have not thought about?

Thank you very much for your interest.
Kind regards,

[Adrian II]

Just to rule out component failure, hot-wire a lead from the battery directly to the coil and see if you have sparks then. 

A.

[AzCal Retred]

Make certain the kill switch is working.

[AzCal Retred]

Make certain the kill switch is working properly, it's in series with the lead going to the points.

As Adrian says bootlegging in a fused jumper to the (+) side of the coil assures that there is voltage actually applied to the coil. A 5 Amp fuse lessens the severity of any mistakes in hook up.

If applying a direct (+) voltage doesn't resolve it, you'll need to troubleshoot deeper. The (-) wire leaving the coil grounds the coil high side winding through the points. The primary winding "saturates" when the points are closed, developing a magnetic field within the spark coil extending beyond the primary winding to include the secondary coil winding. When the point cam opens the contact, the primary coil field collapses and a high voltage is generated on the secondary winding side on the spark plug lead, creating the spark.

With a VOM meter:
1) verify that DC voltage is getting to the Coil (+) when the key is ON.
2) Disconnect the coil (-) wire. Verify on the Ohm scale that this wire has maybe 1 - 2 Ohms or less to chassis ground when the points are closed.
3) Verify also that the resistance goes to infinity when the point cam opens the points.

If all this is proper, the next probable failure points are the spark plug and the condenser. Renew as necessary, reassemble and kick thru vigorously with the spark plug out of the cylinder head, lying on the head, metal touching, so as to have a path to chassis ground for the spark. A good spark will jump 0.025" - 0.040" in open air.

Good hunting - ACR -

[AzCal Retred]

From Soulforge: Thank you very much for your insight.
I am going through what you have advised.
1. Make certain the kill switch is working properly, it's in series with the lead going to the points.
--> Yes it works.
2. As Adrian says bootlegging in a fused jumper to the (+) side of the coil assures that there is voltage actually applied to the coil. A 5 Amp fuse lessens the severity of any mistakes in hook up.
--> I am not sure how to bootleg, could you elaborate in more detail?
3. With a VOM meter:
1) verify that DC voltage is getting to the Coil (+) when the key is ON.
--> Yes, voltage is read.
2) Disconnect the coil (-) wire. Verify on the Ohm scale that this wire has maybe 1 - 2 Ohms or less to chassis ground when the points are closed.
--> shows 0.6 Ohm.
3) Verify also that the resistance goes to infinity when the point cam opens the points
--> Nope. still shows 0.6 Ohm.
Can you advise me on solving this issue?
Thank you very much.

(ACR) Electrical troubleshooting is an exercise in methodical logic. EACH part of the circuit you are examining has to be as "stand alone" as possible.
I assume that you are looking ONLY at the distributor, reading thru the single conductor wire going into the distributor?
The condenser is an open circuit as far as DC from your VOM is concerned.
The contact points are the ONLY pathway to chassis ground on this wire leading into the distributor.
Either:
1) the wire leading to the points is chafed & grounded to the distributor housing.
2) The point assembly wiring is incorrectly assembled and is grounded to the distributor housing.
3) the points aren't opening.
4) The point spring is mis-positioned & touching the distributor housing.
5) The condenser is dead shorted to the distributor housing.

AFTER you have verified the distributor is functioning properly, ONLY THEN reconnect it to the rest of the wiring.
The KISS principle is 100% suitable to troubleshooting!

Good Hunting - ACR -

[soulforge]

Dear ACR,

I am following your advice but here is my current situation.

1) I have double checked the main wire harness and can confirm that it is as the diagram(which hopefully is a correct one!)
2) Distributor housing including the rotatable back plate always have continuity with Frame as it should.
3) The fixed point also has continuity with back plate which makes sense.
4) The movable point has continuity with back plate ONLY when the both points are met BUT when Key On and Kill Switch ON it no longer has continuity.

I believe the ignition coil is fine since it is a new product from HMC(item number 92025) but I lack the knowledge of testing it.
Regardless, the ammeter does not deflect back to zero hence no spark at all.

DC Voltage is read from Coil (+) when Key On of a minimum 10.65V (Battery is also fully charged and when separately read shows a minimum 12. 45V)
I tried direct contact from Battery (+) to Coil (+) and kicked a lot but no spark.

Could you advise me more on this matter? I am getting very frustrated. Sobs.

I am assembled the point as attached. I doubt it is wrong but worth confirming.

[soulforge]

You previously mentioned that,

3) Verify also that the resistance goes to infinity when the point cam opens the points.

The resistance remains the same when point cams are open or closed. Hence this might be the reason but I lack how to solve it.
A part of me thinks that it might be something awfully simple but for now my head is all but boiled.

[Paul W]

Try temporarily disconnecting the condenser. In the past I’ve had faulty ones cause breakdowns (admittedly cars, but the principle is the same). If the coil shorts out, the current to the coil stays connected even when the points open.

When doing this, the points will spark so don’t run the bike like this because the points will blacken.

[AzCal Retred]

SoulForge - here is an electrical elementary of how your ignition coil & points should work, according to your wiring diagram.

You have to be methodical, do not "flail". I can't really tell what you did from your description, try to be very clear. Did you disconnect the distributor wire? Did you read back through this wire to the distributor? Did the distributor function correctly when isolated, i.e., grounded through the disconnected distributor wire ONLY when the points close? If so, the problem is elsewhere.

The main switch has two contacts and does two things: it connects the battery to the circuit when "ON", and grounds the coil when "OFF".
In the elementary I have you lift the (+) wire going to the coil for troubleshooting the "Key OFF" circuit AFTER you have proven the distributor function. Is this clear why?

[Paul W]

Try temporarily disconnecting the condenser. In the past I’ve had faulty ones cause breakdowns (admittedly cars, but the principle is the same). If the coil shorts out, the current to the coil stays connected even when the points open.

When doing this, the points will spark so don’t run the bike like this because the points will blacken.

I meant to write “if the condenser shorts out”, not the coil.

[mrunderhill1975a]

Follow AzCal response. Also, is the photo you show of the points at TDC (top dead center)?  if so, the points are still closed, will not spark if points do not open.  If closed at TDC, you need to adjust the points gap to about .014 inch (the thickness of a matchbox cover) at TDC.

[soulforge]

Dear ACR,

Thank you for your support.

Here followings my findings and also some basic questions which I now am questioning.

For starters, to understand better the diagram you attached, is the 'dual contact main switch', the key switch?
Also you mentioned the same symbol for both OFF and ON thus I am a bit confused. Please see attached. 


1. Key switch: Has 4 wires / 2 wires(Black, Black&Red) are connected both when key is ON and OFF / the other 2 wires(Res, Red&white) only connect when ON.
2. Distributor: I have disconnected the blade connector and confirm that the back plate(or frame) and disconnected blade connector to the distributor side connects only when point is closed
3. Coil: I have removed wire to coil (+) leaving the wire to coil (-) connected. I have also disconnected the blade connector to the distributor and check the disconnected blade connector to the main harness side.
1) the blade connector shows continuity to frame for both Key ON and OFF when kill switch is ON. And is discontinued for both Key ON and OFF and kill switch is OFF.
--> You mentioned that it should not show continuity when Key ON. Hence, I am trying to find out why this happens.

Also, concerning the distributor cam, am I correct in understanding that at TDC the point should be open 0.4mm? If I remember correctly it should be closed and open at 0.8mm before TDC.

Kind regards,

[AzCal Retred]

Soulforge: good report.
From your readings, it appears that the main key switch has a "b" contact that is stuck closed or shorted.
The main switch has two contacts - the "a" contact (red & red/white) is closed when the key is ON; this is an "a" pallet switch configuration. By your readings it appears to be operating correctly.
The second contact is a "b" contact - closed when switch OFF ( black & black/red ). By your reported readings it is not changing position, thus the coil cannot produce a spark because the points cannot open the circuit to interrupt current flow.
You also report that the points are operating cleanly, i.e., closing & opening and showing no unexpected circuit resistances. This is good.

What I would do next is to start with key switch OFF, Kill Switch to RUN:
Isolate the coil (+) from the motorcycle's circuit by lifting the (+) lead.
Reconnect the distributor blade wire.
Roll the engine over until the points are full open.
Read continuity from coil (+) terminal to ground - it should be near infinity ohms.
IF NOT - unplug the key switch or disconnect the red/black & black pair. This removes the Main Switch "b" pallet switch from the circuit.
Recheck the readings, continuity should be near infinity ohms.
(IF STILL NOT - lift the other coil lead running to the points and verify the coil isn't shorted internally. This is low probability but possible.)
With coil reading "open" to ground with points open, roll engine to where points close. Verify continuity to ground through coil (+) terminal.
At this point the circuit is capable of making a spark if battery (+) is applied to the coil (+) terminal.
Run a 5A fused jumper from battery (+) to the coil (+). Kick over and observe (NEW) spark plug for spark. When spark seen, disconnect jumper.

As far as ignition timing, the points are supposed to just crack open when the engine is on the compression stroke, 0.8 mm Before Top Dead Center (BTDC). If they crack open at 0.4 mm BTDC it will still start just fine. The point backing plate is used to adjust ignition timing, moving it within the slots allotted. I use the disconnected distributor blade connector to read point opening, my VOM has a "buzzer" continuity setting that's useful.

Point maximum gap opening is unrelated to this timing. They need to open enough to "break" cleanly. Mine routinely run at about 0.5 mm.

Also - wiring is a bit variable from the factory. You also don't know what the Previous Owner (PO) has done. Using the best wiring diagrams you find and CONFIRMING by logical testing what you actually have is the best method. Don't forget to document what you find.

Run these tests & let me know what you find. - ACR -


1. Key switch: Has 4 wires / 2 wires(Black, Black&Red) are connected both when key is ON and OFF / the other 2 wires(Res, Red&white) only connect when ON.
2. Distributor: I have disconnected the blade connector and confirm that the back plate(or frame) and disconnected blade connector to the distributor side connects only when point is closed
3. Coil: I have removed wire to coil (+) leaving the wire to coil (-) connected. I have also disconnected the blade connector to the distributor and check the disconnected blade connector to the main harness side.
1) the blade connector shows continuity to frame for both Key ON and OFF when kill switch is ON. And is discontinued for both Key ON and OFF and kill switch is OFF.
--> You mentioned that it should not show continuity when Key ON. Hence, I am trying to find out why this happens.

Also, concerning the distributor cam, am I correct in understanding that at TDC the point should be open 0.4mm? If I remember correctly it should be closed and open at 0.8mm before TDC.

[soulforge]

Dear Friends,

I am pleased to share with you that I have finally fixed the problem.
My sincere gratitude to you all and especially to ACR!

The main issue was that I put too much trust in the currently installed parts.
I was so focused on my newly made main harness and other newly installed parts that I had thought less of the already there parts.

Thanks to ACR's detailed support, I finally figured that the sub-harnesses and some others such as the ignition switch were delaying my finish on this bike.
I just started the engine 30 minutes ago and took it out for a short ride, which was beautiful!

Over my years, I have never had to touch so many electric parts on an Enfield such as this, but then the current owner informed me that this bike had been parked outside whilst half open thus who knows what might have happened.

Thank you again everyone!
Have a lovely weekend riding!

[AzCal Retred]

Glad for your success, and a big THANK YOU for buckling down and methodically beating this problem into submission!
Electric bits are good for 30 seconds or 30 years, and sometimes just dead in the box. 
Don't assume anything and you're way ahead of the game, that's what I've learned.

How about some pix of the ride? 

Best wishes - ACR -