1948 Iron 4G Coil Ignition

Anything about Ariels
chris.matthews
Posts: 34
Joined: Wed Oct 16, 2013 6:29 am
Location: Tokyo, Japan
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby chris.matthews » Sun Oct 06, 2019 9:14 am

Hello Folks,
Let me give you an update of Friday & Saturday business.
1. I verified the cb points are at 12 thou.
2. I took the mag sprocket off its taper and re-set the Points Opening & #1 Piston Position.
3. I put the sprocket back on and tightened the nut.
4. I re-checked the timing (it sometimes moves on tightening).
5. I am absolutely convinced the points timing is good.
6. I verified the HT distributor rotor is pointing at #1 plug lead pickup.

Thus encouraged I was convinced it would start - NOT A GLIMMER

My wife barely knows the difference between front or rear of the bike - but she made a comment "If hardware is all OK, then it must be a Human Problem". She might well be correct.
Surely I must be doing something wrong.

Please let me explain what I have:
1. Negative Earth.
2. Power (positive) comes from Battery to Ammeter through Ignition Switch to Coil Supply Side.
3. Other side of coil is connected to cb.
4. Ignition ON and cb points closed I have 0V across cb points and 6V on coil supply and 0V on cb wire.
5. Ignition ON and cb points OPEN I have 6V across cb points and 6V on coil supply and 6V on cb wire (hence 0V across coil).

I wonder if this 0V across coil is my problem - head scratching was interrupted by World Cup Rugby.

Any bright ideas,
Best regards
Chris.

User avatar
Bob.Murphy
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 881
Joined: Thu Nov 29, 2012 10:32 pm
Location: Kirkliston, on the West side of Edinburgh.
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby Bob.Murphy » Sun Oct 06, 2019 11:08 am

chris.matthews wrote:
4. Ignition ON and cb points closed I have 0V across cb points and 6V on coil supply and 0V on cb wire.
5. Ignition ON and cb points OPEN I have 6V across cb points and 6V on coil supply and 6V on cb wire (hence 0V across coil).
Any bright ideas, Chris.


Chris,

With the points open you won't see much voltage across the coil as the primary winding resistance is quite low.

I would be interested to see what the current draw is when the points are closed - can you put an Ammeter in the circuit and see?

To test the coil:

Remove the CB lead from the coil and replace it with a loose piece of cable with a bare end.

Remove the coil's HT lead from the distributor cap and hold it near something that is grounded and not painted.

With the ignition ON - do you get a spark from the HT lead when the loose wire is flicked against the frame/grounded metal ?

That will show whether the coil is working or not.

If the coil is working in isolation, but not when the ignition system is assembled, it indicates an open circuit somewhere. Check for earth continuity at the points when they are closed.

You have probably done all of this, if so apologies, but the system is quite straightforward and it should just be a matter of checking each item in sequence along its length.

Good luck.

Bob.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1808
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby paul.jameson » Mon Oct 07, 2019 7:43 pm

Picking up on your wife's point and given that you have just re-timed everything, are you sure that you have timed on the compression stroke rather than the exhaust stroke?
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

john.whiting
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1442
Joined: Sun May 22, 2011 2:10 pm
Location: Brisbane QLD
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby john.whiting » Tue Oct 08, 2019 4:46 am

If so,just swap the leads in the dizzy cap,diagonally...............I was shown a sure fire method of checking timing many years ago.....remove a plug,and reconnect the lead,hold the plug in the palm ,put your thumb over the plug hole,crank the motor.....you should get a bite same time as the thumb is blown off the plug hole........obviously do do this if you have heart trouble,or the like.

chris.matthews
Posts: 34
Joined: Wed Oct 16, 2013 6:29 am
Location: Tokyo, Japan
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby chris.matthews » Wed Oct 09, 2019 12:48 pm

Hello from Tokyo
Let me give an update.
First a couple of Open Items - I was doing the timing on the right stroke: The coil is alive and well and I have not electrocuted myself.

On Monday afternoon, the Japanese Brains Trust descended on me and they were convinced they would get the 4G running - after several hours they couldn't and they decided they would regroup and come again today (Wednesday).

Today, we found points timing with timing chain / sprocket was correct but some fine adjusting was done moving the points backing plate (as John described). One thing we found, don't set the timing by backing up the rear wheel - it makes the timing chain slack. Always set by moving on the KS or forward on the wheel.
The distributor timing was slightly out - roughly equivalent to one tooth on the distributor drive gear.
It was thought these two problems alone would not be enough for the "Not a Glimmer" situation.
We also set the manual Advance / Retard.
We then had a few pops & bangs and 'nearly' running.

So we looked at the Solex.
There was a big debate about Float Height - I thought it was slightly impractical as there is nothing we can do about the float height.
But it was better to keep this thought to myself (is there anything we can do about it ?)
As expected, plugs at Front #1 & #4 were dry but Rear #2 & #3 were damp.
I feel this is simply the geometry; its easier for the fuel to drop into the rear cylinders nearest to the carb.
Bike ran for two minutes and stopped (like it did 3 months ago) - consensus was "Fuel is Restricted".
We did all the usual stuff and we removed the fuel filter which is in the entry to the Float Chamber, its very tiny and a very fine mesh.
Bike ran much longer and did not stop.
The mixture seems all over the place and this will be investigated in the coming days.

Brains Trust left in late afternoon have been here all day.
Current thinking is find & fit a large in-line filter; do some mixture investigation and adjusting.

We are definitely making progress.
Long Story made short - IT RUNS......….

I'm hoping this saga is coming to a close (fingers crossed).
I would like to thank everyone on the forum for their support, advice and guidance.

I tried to get Brains Trust interested in Velocette Starting, so far its " No thanks - they are pigs to start".

Best regards
Chris.

User avatar
simon.holyfield
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3519
Joined: Mon Oct 17, 2011 11:16 pm
Location: Norfolk
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby simon.holyfield » Wed Oct 09, 2019 5:07 pm

Chris, there's probably a few posts on float height. I think many of us have two fibre washers under the valve to lean out the mixture. Mine certainly runs better that way.

Anyway, congratulations! Glad you are getting somewhere.

On the fuel filter, Amelia has quite a coarse mesh filter there. I probably blogged making it, I'm sure at least there are pictures of the gauze I used. It's nothing like as fine as the usual fuel tap gauze.
cheers

Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'78 CX500
http://ariel-square-four.blogspot.com

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1808
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby paul.jameson » Wed Oct 09, 2019 8:32 pm

Chris,

I am delighted at your progress. The problem always did sound like fuel starvation. Solex adjustments are not too easy or too obvious. Jens Beusse and Otto Mederle, both from Germany, are the serious experts on these carbs. Apart from anything else, they know which parts should be fitted - and which parts (usually from cars) will fit but are incompatible with Ariels. As a result of their advice, I am part way through altering the carb on my 1936 4G so that the butterfly opens in the correct direction. I thought it a minor point, but they showed me how opening correctly would increase air flow across the hole from the slow running system which should eliminate the poor pick up from slow running I have had. A 10 page article is in course of preparation by them for Cheval. In the meantime, as they are not on this group, feel free to PM any questions to me and I will email them as necessary for you.

Paul
Paul Jameson
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

nevhunter
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3730
Joined: Tue May 10, 2011 9:42 am
Location: Victoria.. Australia.
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby nevhunter » Thu Oct 10, 2019 1:16 am

Velocettes are still conventional engines but the K/S doesn't move the engine very fast. If the magneto is OK they start fine IF you have the technique of starting a single covered/learned. Never have your leg dead straight and have the foot so as to enable it to give way to a fast returning pedal, Over the years I've seen Nortons, Gold stars, some hot Ariels and a few others do considerable damage to peoples feet and legs/hips. It pays to get a few clues from some of the old codgers if you're a newbie, fresh off electric start fours etc. Nev

john.whiting
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1442
Joined: Sun May 22, 2011 2:10 pm
Location: Brisbane QLD
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby john.whiting » Thu Oct 10, 2019 3:09 am

Seems like the bike stopped in the first place because of the uncertain point gap and timing,then fiddling with the carby just made it worse......certainly didnt help....the fate of many a square four in years gone by.

User avatar
Eero.Korhonen
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 841
Joined: Tue Sep 04, 2012 10:02 am
Location: Oulu, Finland
Contact:

Re: 1948 Iron 4G Coil Ignition

Postby Eero.Korhonen » Thu Oct 10, 2019 5:45 am

Hello Chris,
That is really good news, I hope you can get it on the road soon.
Br, Eero
Ariel VH 1954, IZH 350 1962, H-D Sportster Hugger 1992, AOMCC Member 133


Return to “Ariel Talk”

Who is online

Users browsing this forum: No registered users and 5 guests