Just won't start

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Boris64
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Just won't start

Post by Boris64 »

After a few years of fun and absolutely no issues, stopped and just won't start.

Everything that runs off the electrical circuit is working - lights, horn, starter, heater fan, pump etc.. Turns over no problem but no spark in the dizzy.

I've never had a problem with mechanicals but sparks is another story.

Hopefully something simple.

Thanks

Actually on the old web site (been away for a while) I would have posted this under electrical but can't find it on the new format - apologies.

Pete
myoldjalopy
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Re: Just won't start

Post by myoldjalopy »

Yes, probably something simple. When you say "no spark in the dizzy", do you mean there is no spark at the king lead from the coil to the dizzy, or no sparks at the plugs? That will help narrow down where you need to look. If the latter, I would suspect the rotor, dizzy cap or leads or plugs (although very unlikely all leads and/or plugs would fail at the same time).
Of course, if you have an electronic ignition fitted, it may be kaput. Or have you still got the points set-up?
If you can answer these questions we can help you in more detail.......in a logical sequence of tests to solve the problem more quickly and prevent wasting money on replacing things randomly that don't solve the problem, leaving you ever more frustrated!
Last edited by myoldjalopy on Mon Apr 02, 2018 10:27 am, edited 1 time in total.
simmitc
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Re: Just won't start

Post by simmitc »

Ideally you should not have a spark in the dizzy as the condenser is there to stop the points arcing, but s small spark is not unusual. Take a logical route:

You need 12 volts reaching the coil. Remove the low tension lead from the coil to the distributor. Using a multimeter or a test lamp, confirm that you have 12 volts on the coil switched terminal and the other low tension terminal. Refit the low tension lead from the coil to the dizzy. Turn the engine by hand so that the points are open and now test that you have 12v reaching the dizzy. These tests confirm that there are no broken or loose wires and that the coil has not failed on the low tension side.

If above is OK then test the HT side: With everything in place, remove the HT king lead (between coil and centre of dizzy) from dizzy cap and place the end close to the engine block. With the ignition on, spin the engine over as usual. You should see a good spark between the lead and the block.

Let's take this in easy stages, so report results of above tests and we'll know where to look next.
TDV102
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Re: Just won't start

Post by TDV102 »

Check the earth straps
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Boris64
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Re: Just won't start

Post by Boris64 »

Thanks for prompt responses.

I'd forgotten how helpful everyone is here.

I've been busy fitting a monoshock to a Honda CB500 Four and trading correspondence on a US site - lots of hostility and insults seems to be the norm.

With regard to the Morris - dizzy cap off and no spark/arking across the points (I'd expect something).

Assume earth is ok as power to everything else.

I'll run the suggested checks but could use a bit less rain!

Thanks

Pete
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geoberni
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Re: Just won't start

Post by geoberni »

Did you find the problem?
Basil the 1955 series II

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myoldjalopy
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Re: Just won't start

Post by myoldjalopy »

Unfortunately, there are far too many threads that peter out without conclusion. Its a pity because it diminishes the usefulness of this forum for others trying to research similar issues they may be facing. Can I make a plea for people to post the eventual outcome of their problem?
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Re: Just won't start

Post by amgrave »

Seconded

Boris64
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Re: Just won't start

Post by Boris64 »

Gentlemen,

Sincere apologies this went very much on the back burner.

My daughter's return from Uni has brought renewed focus.

I've got an hour before kick off.

I'll let you know.

Pete
Boris64
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Re: Just won't start

Post by Boris64 »

After a quick check, this looked like the problem - centre electrode in dizzy cap missing.

Quick dash to SW London best auto parts store for £10 replacement.

Sadly still won’t fire.
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Boris64
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Re: Just won't start

Post by Boris64 »

Simmitc

I’ve run your checks (as best I understand them) as follows:

1. Disconnected small wire from coil to dizzy as attached photo with ignition on, shows 12 volts
Last edited by Boris64 on Sun Jun 24, 2018 5:07 pm, edited 1 time in total.
Boris64
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Re: Just won't start

Post by Boris64 »

676C9438-AC1D-499F-93A9-973D802357B5.jpeg
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Simmitc

I’ve run your checks (as best I understand them) as follows:

1. Disconnected small wire from coil to dizzy as attached photo with ignition on, shows 12 volts
Boris64
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Re: Just won't start

Post by Boris64 »

Ignition on, no reading across coil terminals. This may be right.
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Boris64
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Re: Just won't start

Post by Boris64 »

Ignition on 12volts between end of small wire from coil to dizzy - just to be sure there is continuity
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Boris64
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Re: Just won't start

Post by Boris64 »

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All wires connected, ignition on, points open, (plastic tie wrap for isolation).

12 volts across coil to fixed side of points.
Boris64
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Re: Just won't start

Post by Boris64 »

King lead removed at dizzy gives strong spark when held against the block.

Unable to upload video.

Simmitc, I believe that’s all your checks. Any thoughts on where to look next?

Thanks

Pete
TDV102
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Re: Just won't start

Post by TDV102 »

Cracked rotor arm?
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amgrave
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Re: Just won't start

Post by amgrave »

Sounds like you need to replace the rotor arm, it might be tracking to earth via the shaft it's mounted on.

Boris64
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Re: Just won't start

Post by Boris64 »

Thanks, I'm out of time now but I'm sure I've got a new rotor arm somewhere.

I remember choosing to continue with the current one as there was lots of issues with rotor arms with rivets in them.

I'll report back.

Pete
myoldjalopy
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Re: Just won't start

Post by myoldjalopy »

As above - rotor arm seems a likely culprit. You can test it in situ by holding (with insulated pliers) the end of the king lead 1/4 inch or so from the top of the rotor arm and turning the engine over. If a spark jumps to the rotor then it is faulty as it should be insulated from earth to enable it to 'distribute' the spark to the four plug leads. If it doesn't spark across to the rotor then check the fuel pump is pumping properly and that the carb is not sticking............ and double check you put the plug leads on in the correct order when fitting the new dizzy cap - 1342 anticlockwise.
If it is the rotor arm, get one from the famous Distributor Doctor......after suffering a few failed rotors a few years ago, I got one of his red ones and no problems since 8)
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