Electric buggery – No Sparks!

Guys, after getting my 400D on the road, I’m on holidays and decided to tackle my (very decent looking) Rd 250 C project. Good looking, good compresh working lights and all…
except I am not getting a spark!
Using my Good daily bike battery (400D top notch and holding charge)
Coils tested (bad one replaced)
Hi-tension leads tested OK (ther’s continuity and i can check the coils through the lead)
Going without plugs or cap at the moment, just trying to get it to spark against the heads.
Fuses checked and replaced as needed

I’ve got power at the points, at the coils (Red/white lead) and at the brown iggy switch wire (this changes as the points open) To get a Voltage reading, I need to use the Batt’s neg pole… getting no readings when using the frame as ground. Still no fat blue spark in sight…

What am I missing???

I also cleaned the tank and the carbs are holding the fuel in… plugs wet… it’s getting thruh… I just need an effing spark to to start her…

EXERPT FROM THE THREAD:
Dead condensors?
IP Logged
mervin 
Moderator Group 

Crab Transporter

Joined: 02/Aug/2002 
Location: Venezuela 
Online Status: Offline 
Posts: 1902 
Posted: 22/Apr/2007 at 10:40pm
Try running another earth wire from battery to frame sounds like the earth is not grounding very well although the lights etc working maybe worth a try 
Merv
IP Logged
AlexS 
Club Member 

Joined: 15/Nov/2003 
Location: United Kingdom
Online Status: Offline 
Posts: 153 
Posted: 23/Apr/2007 at 2:26pm
I would tend to agree with Mervin. It does sound like a bad earth between the battery and the frame. I’m also wondering about the earth connection between the engine and the frame (someone feel free to contradict me but 400′s have rubber mounted engines and so must have an earth cable of some description).
Generally when a condensor fails you can tell by “flicking” the points open with an electrical screwdriver. If you get a very big blue spark at the points then the condensor has failed. It will be very obvious.
IP Logged
mervin 
Moderator Group 

Crab Transporter

Joined: 02/Aug/2002 
Location: Venezuela 
Online Status: Offline 
Posts: 1902 
Posted: 23/Apr/2007 at 2:56pm
Yes did not think about that rubber mounted engine no ground on enginme
Merv
IP Logged
spike 
Back Lane Scratcher 

Joined: 18/Oct/2005 
Location: Switzerland 
Online Status: Online 
Posts: 82 
Posted: 25/Apr/2007 at 12:09pm
I fiddled with it again… Not much result…

If I open them (with the cam), the mobile arm is live, the fixed dead, so it’s OK
I don’t get power on both arms of the points when there closed… the fixed one is stil dead…

I gather that’s not normal… Is it?

Otherwise, no spak jumping at the gap when opening points.
Where is supposed to be the engine to frame earth lead. I can always bung up one for test, but would like the bike to stay original.
IP Logged
RDly 
Moderator Group 

Shitting in Ardons alleyway

Joined: 12/Jun/2002 
Location: Pakistan 
Online Status: Offline 
Posts: 5377 
Posted: 25/Apr/2007 at 2:02pm
There is no earthing point for the engine to frame, although I’ve never heard of one not earthing as the chain and cables can achieve that.
Run a temporary earth from the engine to the frame, as if the engine’s not earthed then you’re not going to get a spark no matter what!
As for the points, the fixed arm is earthed so that will remain dead, also when the points are closed they will remain dead but when open you should have 12 volts on the moving points arms.
I would suggest you disconnect the condensors, they aren’t needed to achieve a spark, they just prevent premature burning of the points surfaces.
If you have 12 volts at the points I would turn my attention towards the coils. Have you got continuity from the orange and grey wires from the points ends to the coil ends?

Try that for now, but earth the engine to the frame first 
IP Logged
RDly 
Moderator Group 

Shitting in Ardons alleyway

Joined: 12/Jun/2002 
Location: Pakistan 
Online Status: Offline 
Posts: 5377 
Posted: 25/Apr/2007 at 2:12pm
Actually I just remembered. The engine earths via the negative/black wire from the stator loom, so that’s a good place to check as you may have a crummy connector somewhere 
IP Logged
spike 
Back Lane Scratcher 

Joined: 18/Oct/2005 
Location: Switzerland 
Online Status: Online 
Posts: 82 
Posted: 26/Apr/2007 at 8:28am
I’m just suddenly thinking I must have an earth because I’m using the crankcase as negative for testing… I am getting a reading on the points… hence it’s earthed!

Still NO SPARK, coils’ primary and secondary windings all test OK, and fuses are good too…
will try disconnecting the points.
IP Logged
spike 
Back Lane Scratcher 

Joined: 18/Oct/2005 
Location: Switzerland 
Online Status: Online 
Posts: 82 
Posted: 02/May/2007 at 8:20pm
Sorry to bug with that, but it’s annoying…

I disconnected the condensers and started checking the wires from the generator towards the coils (without a battery):

both grey and orange from the points to the coils show continuity,
but the green wires coming from the alt. brushes don’t show anything, no continuity: normal?
are they needed for the ignition system?

the red/white is alive when the the switch is on (with battery), so my kill switch should be ok.
Brown wire (in the headlight) is alive as per Haynes…

Getting non plussed.

Hints?
IP Logged
mark in sc 
Club Member 

Joined: 07/Jan/2003 
Online Status: Offline 
Posts: 2672 
Posted: 02/May/2007 at 8:22pm
green wire gets voltage from regulator to excite the rotor. should see voltage on it, (remove brush) with key on. if not, your regulator is sacked.. or the wiring is.
IP Logged
spike 
Back Lane Scratcher 

Joined: 18/Oct/2005 
Location: Switzerland 
Online Status: Online 
Posts: 82 
Posted: 04/May/2007 at 8:13am
Hi Mark,

Green wires going to reg show continuity and voltage when key is on…

Is it possible that coils give good readings but are shot?

I mean everything test OK, but I’m not getting a spark… getting double nonplussed 
IP Logged
RDly 
Moderator Group 

Shitting in Ardons alleyway

Joined: 12/Jun/2002 
Location: Pakistan 
Online Status: Offline 
Posts: 5377 
Posted: 04/May/2007 at 9:37am
This is beginning to sound like your coils are goosed, unusual for both to go at the same time!!!
The generator is not required for a spark, only a nicely charged battery is.

I would start again but concentrate on only one side to preserve the battery. Disconnect both grey and orange wires from the points, you don’t need points to get a spark, earthing either one should make a spark at the HT cap.

Sorry I can’t finish at the moment I will be back later :rolleyes:
IP Logged
RDly 
Moderator Group 

Shitting in Ardons alleyway

Joined: 12/Jun/2002 
Location: Pakistan 
Online Status: Offline 
Posts: 5377 
Posted: 04/May/2007 at 2:47pm
Ok to continue, have you tried removing the orange or grey wire from the coils?
Turn on the ignition and make sure you have battery voltage at the red/white wire to the coils. If possible check this voltage with the wire still connected by pushing your meter probe inside the bullet connector sheath.
Now assuming you have a positive reading, disconnect the orange and grey wires from the points and connect a length of wire to either of the wires from the coils. Now with the ignition on, briefly earth the wire and look for a spark at the end of the HT lead. If you still have no spark then the coil/s are almost certainly duff as all your other checks indicate the rest of the system is fine.

Let us know how you get on? I’ll pop back in later on

KEEF