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A65 L 1970 starting troubles #679604
01/01/17 7:35 pm
01/01/17 7:35 pm
Joined: Oct 2016
Posts: 52
U.K. Midlands
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Ian T Offline OP
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Ian T  Offline OP
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A little advice if I may

I bought my A65 L 1970 in Nov. It's a us import back to uk. It's not yet registered so I'm going through it ready for uk mot. It started, albeit reluctantly after a few kicks so I was confident that after a few mods it would be a much better starter- how wrong I was.
It's all back together now and once started it ticks over, pulls and runs well. It starts well when warm.

This is what I have done:
New battery
Changed plugs, oils.
Checked valve timing as per book
Fitted new Boyer EI- timed using timing slot in crank , timed at fully advanced ( checked static then fine tuned with strobe)
Fitted two new 6v coils- wiring checked and rechecked
Cleaned out carbs, in particular, cleaned out pilot circuit
Bi passed fuel tank using fresh fuel in temporary bottle ( to eliminate possibility of potential debris in tank)

My starting procedure is tickle carbs till fuel spills, prime engine with a couple of kicks, ignition on then strong kick on starter. Choke sliders do not seem to affect running or starting so set slides in up/off position

After about 20 kicks I sometimes get a little splutter then 10 more sometimes it starts. Once it starts and is run warm she will easily restart.

I must stress this is a cold start issue only as she runs well.

Is there something I'm missing ?



Last edited by Ian T; 01/01/17 8:03 pm.

Sunbeam S7 Deluxe 1949
Honda CB750 K3 1972
Suzuki GT500 1977
BSA A65 Lightning LA Y 1970
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Re: A65 L 1970 starting troubles [Re: Ian T] #679611
01/01/17 8:23 pm
01/01/17 8:23 pm
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Posts: 3,245
arkansas
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leon bee Offline
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arkansas
Check the plugs after 6 good kicks. Then put in a fresh pair anyway and set aside the others for cleaning. And make sure the carb slides are exactly synchronized as they lift. I've been stumped by bad needle jets before.

Edit to say make sure they are Champion plugs. (Just my opinion)

Last edited by leon bee; 01/01/17 8:25 pm.
Re: A65 L 1970 starting troubles [Re: Ian T] #679613
01/01/17 8:27 pm
01/01/17 8:27 pm
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arkansas
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leon bee Offline
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arkansas
And make sure the battery is hot, whether it's new or not.

Re: A65 L 1970 starting troubles [Re: Ian T] #679618
01/01/17 8:43 pm
01/01/17 8:43 pm
Joined: Oct 2007
Posts: 1,526
Auckland NZ
Ignoramus Offline
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+1 on battery


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
Re: A65 L 1970 starting troubles [Re: Ian T] #679631
01/01/17 10:43 pm
01/01/17 10:43 pm
Joined: Aug 2001
Posts: 3,757
argyll. scotland, uk
gavin eisler Offline
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argyll. scotland, uk
Dodgy ignition switch maybe? Strange the choke slides have no affect,they make a big difference to my bike. What method did you use for cleaning the pilot jet,what settings are the pilot air screws at? I prefer to clean the jets with a#78 drill and start with the air screws 1.25 turns out from closed.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 L 1970 starting troubles [Re: Ian T] #679638
01/02/17 1:23 am
01/02/17 1:23 am
Joined: Aug 2001
Posts: 4,369
Owego, NY, USA
Mark Z Offline
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Owego, NY, USA
My starting procedure is tickle carbs till fuel spills, prime engine with a couple of kicks, ignition on then strong kick on starter. Choke sliders do not seem to affect running or starting so set slides in up/off position

Try skipping the "prime engine with a couple of kicks" step.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 L 1970 starting troubles [Re: Mark Z] #679639
01/02/17 2:15 am
01/02/17 2:15 am
Joined: Sep 2013
Posts: 1,664
Pacific northwest
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quinten Offline
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Pacific northwest
Originally Posted By Mark Z
My starting procedure is tickle carbs till fuel spills, prime engine with a couple of kicks, ignition on then strong kick on starter. Choke sliders do not seem to affect running or starting so set slides in up/off position

Try skipping the "prime engine with a couple of kicks" step.


+1
.

Re: A65 L 1970 starting troubles [Re: Ian T] #679696
01/02/17 11:34 am
01/02/17 11:34 am
Joined: May 2013
Posts: 4,765
Rotherham - S. Yorkshire
Allan Gill Offline

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Most important question is HOW did you clean out your pilot jets?

The pilot jet should be of the pressed in bush type, a 0.016" guitar string will be of the right size, but the best way to remove any crud is with a #78 drill bit (they are tiny) and glued into a aerosol straw. Work the jet in and twist and pull outwards. This will screw the crud onto the drills twist and pull it out, as opposed to packing it further in which the guitar string does.

If the carbs are set up right they should be a gnats whisker of a gap under the slide that can be seen with a torch. mixture between 1-1.5 turns out on the air bleed screw.

Also this time of year you will need choke (you may not have them fitted, they are often removed facepalm )


beerchug
Re: A65 L 1970 starting troubles [Re: Ian T] #679713
01/02/17 12:27 pm
01/02/17 12:27 pm
Joined: Sep 2006
Posts: 85
Wales
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Ray Smith Offline
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Wales
I used to have the same problem with my 1970 Thunderbolt.Now when cold particularly when it has been stood for a week or so I really flood it with the tickler.No priming kick. Good kick on the starter and she starts. Always within 3 kicks usually 1.
You"ve sorted the usual culprits she aint getting enough gas
Good luck

Re: A65 L 1970 starting troubles [Re: Ian T] #679714
01/02/17 12:40 pm
01/02/17 12:40 pm
Joined: Feb 2008
Posts: 4,260
New Jersey USA
Tridentman Offline

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When we say that these Brit bikes have "character" very often it means that although ostensibly identical they can require different treatment to start and run properly.
For example over the years I have had Brit bikes that do not need chokes to start and I have had Brit bikes that will not start without chokes.
My advice would be to play more with the chokes.
FWIW I have never had to set at half choke---it is either "all or nothing".
HTH

Re: A65 L 1970 starting troubles [Re: Ian T] #679717
01/02/17 1:06 pm
01/02/17 1:06 pm
Joined: Aug 2012
Posts: 309
Hampshire, England
DoubleDiamond Offline
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A couple of thoughts...

You say you have cleaned out the carbs - are you sure that the internal jets/needle/slide are set correctly and in good condition?

On the basis that you do have a strong spark, my suggestion re the chokes (they are balanced?) is to put the chokes ON (down) then kick.

Its cold here in the UK at the moment so you do need extra fuelling at start-up. Remember that only about 10% of the hydrocarbons in the fuel are sufficiently volatile to evaporate in cold temperatures, which is why you need, initially at least, a very rich mixture to get the bike to fire.

In normal operation when warmed up, the mixture (air to fuel) ratio will be about 12:1 or 13:1. From the above you can deduce that it will need to be about 2:1 at startup when cold!

Also, if the engine will run and tickover without some choke in cold weather then the carbs are too rich.


BSA: '71 B175; '68 B25; '71 A65; '71 A75
Triumph: '87 T140; '72 T150v
Re: A65 L 1970 starting troubles [Re: Ian T] #679760
01/02/17 4:25 pm
01/02/17 4:25 pm
Joined: May 2013
Posts: 4,765
Rotherham - S. Yorkshire
Allan Gill Offline

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Another question is how old is the fuel, winter grade fuel is a different blend to aid starting (more voletile light ends which aid ignition)


beerchug
Re: A65 L 1970 starting troubles [Re: Tridentman] #679761
01/02/17 4:27 pm
01/02/17 4:27 pm
Joined: May 2013
Posts: 4,765
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Rotherham - S. Yorkshire
Originally Posted By Tridentman
When we say that these Brit bikes have "character" very often it means that although ostensibly identical they can require different treatment to start and run properly.
For example over the years I have had Brit bikes that do not need chokes to start and I have had Brit bikes that will not start without chokes.
My advice would be to play more with the chokes.
FWIW I have never had to set at half choke---it is either "all or nothing".
HTH


No such thing as half choke on a carb with choke slides, as you say it's all or nothing, otherwise the choke won't do anything again until the carb slide reaches and exceeds half throttle


beerchug
Re: A65 L 1970 starting troubles [Re: DoubleDiamond] #679776
01/02/17 5:50 pm
01/02/17 5:50 pm
Joined: Oct 2016
Posts: 52
U.K. Midlands
I
Ian T Offline OP
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Thanks for all replies.

Today I've bought a couple of NGK spark plugs to replace the 2 week old champions. Still it wont fire even though there is a healthy spark.

I used no 78 drill bit in the brass pilot jet. For future servicing I also undertook the mod as recommended on bushman's carb website to tap out the other side of the carb and blank off with removable AMAL screw. The pilot circuit is definitely clear - I've checked this several times during the non-starting period.

Strange how some bikes start without choke. Here is a pic of one carb with the choke on. Does this look about right or should it/can it be adjusted lower?



Also, I note my needle is set on position 2 (mid way between 1 and 3) whereas the book says 3. The bike runs well like this but wont start. Shall I revert back to position 3 or leave alone?


Sunbeam S7 Deluxe 1949
Honda CB750 K3 1972
Suzuki GT500 1977
BSA A65 Lightning LA Y 1970
Re: A65 L 1970 starting troubles [Re: Ian T] #679787
01/02/17 6:11 pm
01/02/17 6:11 pm
Joined: Aug 2001
Posts: 3,757
argyll. scotland, uk
gavin eisler Offline
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argyll. scotland, uk
Mmmm, it looks like you have covered the carb faults very well. I would temporarily hot wire the ignition by passing the switch in case that has dirty contacts. The choke slides should bottom out when on. All set ups are idiosyncratic, my bike starts from cold without touching the throttle, maybe try adjusting the throttle stop screws up about a half turn each,A65 motors will idle at low rpms but around 1,000 is best.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 L 1970 starting troubles [Re: Ian T] #679789
01/02/17 6:28 pm
01/02/17 6:28 pm
Joined: Apr 2005
Posts: 1,634
Mississauga, Ontario.
A
Adam M. Offline
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Adam M.  Offline
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Mississauga, Ontario.
Did you try to start it without filters ?
If yes try install air filters on her.
If she starts nicely and runs without filters when hot the carbs are set too rich.

Last edited by Adam M.; 01/02/17 6:29 pm.
Re: A65 L 1970 starting troubles [Re: Ian T] #679792
01/02/17 7:09 pm
01/02/17 7:09 pm
Joined: May 2013
Posts: 4,765
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Rotherham - S. Yorkshire
Originally Posted By gavin eisler
Mmmm, it looks like you have covered the carb faults very well.


Really?

Originally Posted By Ian T


Strange how some bikes start without choke. Here is a pic of one carb with the choke on. Does this look about right or should it/can it be adjusted lower?



Also, I note my needle is set on position 2 (mid way between 1 and 3) whereas the book says 3. The bike runs well like this but wont start. Shall I revert back to position 3 or leave alone?



Answer to both these questions.

The choke slide should completely bottom out on the bottom of the carb, otherwise when the slide is closed the choke is. It low enough to function. Without stating the obvious, the choke is to choke off the air supply, if the slide is closed and the choke isn't visible below the cutaway of the slide it isn't choking anything. To have ultimate effect it has to seal off as much air as possible. Halfway up is not doing anything when the slide is down.

If your running standard setup as in silencers and filters then your best starting with stock jetting, that's slide numbers and main jets especially needle position. #3 being the lowest groove on the needle which raises it to be at its richest point.

I will add that those carbs are the originals, who knows what has happened to them in 50 years, the jets could be worn out hence the needle position change and the slides could have worn in the bores which would alter how the fuel is drawn through the carb through vacuum losses.

It might be wise to fit new AMAL Premiers which will certainly help and improve how the bike runs.

As for the none use of choke, winter in California might be lovely, but if a carb is dialled up correctly at the temperatures we're getting at the moment, you need choke. If you don't... then it's too rich when the bike is warm.


beerchug
Re: A65 L 1970 starting troubles [Re: Ian T] #679793
01/02/17 7:12 pm
01/02/17 7:12 pm
Joined: May 2013
Posts: 4,765
Rotherham - S. Yorkshire
Allan Gill Offline

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Rotherham - S. Yorkshire
Just to add a 1970 Lightning should have

Number 3 slide
Needle in position 1 (leanest)
106 needle jet
180 main jet

If by some chance someone fitted it with OIF megaphones, then it's 200 main jet


beerchug
Re: A65 L 1970 starting troubles [Re: Ian T] #679796
01/02/17 7:20 pm
01/02/17 7:20 pm
Joined: Aug 2012
Posts: 309
Hampshire, England
DoubleDiamond Offline
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Hampshire, England
Some further thoughts...

The position of the needle clip will have no effect on starting - it only makes a difference from about 1/3 throttle open.

Looking into your carbs I see that the chokes are not full down. In cold weather, like it is now, you do need to make sure that they fully 'choke' in the down position to get a rich mixture needed for starting.

To repeat what has been said before, if an engine starts easily without the choke ON in cold weather then the carb is very probably set too rich (or the float bowl may be flooding).

HTH


BSA: '71 B175; '68 B25; '71 A65; '71 A75
Triumph: '87 T140; '72 T150v
Re: A65 L 1970 starting troubles [Re: Ian T] #679800
01/02/17 7:43 pm
01/02/17 7:43 pm
Joined: Oct 2016
Posts: 52
U.K. Midlands
I
Ian T Offline OP
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Great advice guys - thanks.

back to work tomorrow so only eves to fettle bike till w/e but will certainly drop choke sliders down to bottom out, replace fuel (its about 2 month old), leave needle in position 2, refit air filers, check ignition switch and try again.
I don't want to buy new amals ATM but may have to if I get no joy.

Will keep you posted.

Thanks once again.

Last edited by Ian T; 01/02/17 7:45 pm.

Sunbeam S7 Deluxe 1949
Honda CB750 K3 1972
Suzuki GT500 1977
BSA A65 Lightning LA Y 1970
Re: A65 L 1970 starting troubles [Re: Ian T] #679926
01/04/17 6:22 am
01/04/17 6:22 am
Joined: May 2004
Posts: 3,674
Sydney Australia
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BSA_WM20 Online content
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Sydney Australia
You still have not answered the compression question.
We need a compression reading wet & dry both hot & cold.
Slightly worn ring can cause very hard cold starting but be OK when hot.
Also remove the balance tube and plug off the holes for the purpose of tuning.
I have seen hundreds of A65's idleing & starting off 1 carb.
Try a shot shot of starter fluid in one side then if it starts, try the other.
Bike starts no problems then the pilot circuit is clogged.
Float valve set too low can also make it a bugger to start due to insufficient vaccuum ( I know that is wrong term, but every one undrstands it ) at kick start speeds.
When warm spray some WD 40 FROM A TRIGGER PACK NOT A PRESSURE PACK ( yes I was shouting ) all around the manifolds to check for air leaks
Again you can get air leaks that close up a bit when the bike gets hot & expands.


Bike Beesa
Trevor
Re: A65 L 1970 starting troubles [Re: BSA_WM20] #679929
01/04/17 7:08 am
01/04/17 7:08 am
Joined: May 2013
Posts: 4,765
Rotherham - S. Yorkshire
Allan Gill Offline

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Originally Posted By BSA_WM20

When warm spray some WD 40 FROM A TRIGGER PACK NOT A PRESSURE PACK ( yes I was shouting ) all around the manifolds to check for air leaks
Again you can get air leaks that close up a bit when the bike gets hot & expands.


I use WD40 from a presurised can with no problems for diagnosis. If you soak the manifold, any leaks will cause the engine revs to stumble.


beerchug
Re: A65 L 1970 starting troubles [Re: Ian T] #680033
01/04/17 8:19 pm
01/04/17 8:19 pm
Joined: Aug 2001
Posts: 3,757
argyll. scotland, uk
gavin eisler Offline
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argyll. scotland, uk
Regarding the pilot circuits,as well as the jets there are two small holes in the floor of the carb bodies on head side of the slide seating zone,these must also be clear.
An alternative to fitting new carbs is to replace the slides, this will help minimise air leaks.
Personally I am not convinced the fuel circuit is the fault,if it starts and runs OK when hot then either you have compression issues or sparks are not good.
Use a meter set on ohms to check resistance across switch contacts,continuity of earth paths, set on volts check battery, check volts at switch and at coils, new batteries can be duds, check battery volts before and after starting. A spark at plug resting on head may not be strong enough to fire under compression.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 L 1970 starting troubles [Re: gavin eisler] #680040
01/04/17 9:16 pm
01/04/17 9:16 pm
Joined: Jan 2006
Posts: 6,876
Laredo (South) Texas, USA
GrandPaul Offline
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Laredo (South) Texas, USA
Originally Posted By gavin eisler
A spark at plug resting on head may not be strong enough to fire under compression.


I learned that in the Navy in 1976; we had a cool compression box with a window that we could connect compressed air to, screw in a spark plug, connect the spark source and test.


GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, some BSA & European
"The Iron in your blood should be Vintage"
Re: A65 L 1970 starting troubles [Re: Allan Gill] #680065
01/05/17 5:33 am
01/05/17 5:33 am
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Posts: 3,674
Sydney Australia
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Except the propellant is very volatile and you are spraying around a hot place with a chance of a stray spark.
While I am just starting on old age eyebrows, singing them off is not part of the "new youthful looking me " clap


Bike Beesa
Trevor
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