The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Joe on 16.05. 2024 18:56
-
Dear All,
I am a new member on this forum although I have been following as a guest from France for a long time.
I have an A10 Golden Flash plunger (1951), and it has never been an easy starter. A few years ago I had the mag reconned in the UK, and it still stubbornly remained a difficult starter. I have a B31 as well which is a really easy two kick job. I recently retired so decided it was time to take this bike in hand and get it sorted.
I decided to convert to EI and for my sins, bought the Lucas dummy mag along with the Vape/Wassell EI system. It's very easy to install and wire up so I thought. But since installing the bike has refused, inspite of much kicking and swearing to even cough.
I have timed it using a wheel to 33-34 degrees BTDC, and confirmed by measuring with a vernier the piston movement
I have set the rotor on the EI at 33/34 degrees full advance BTDC to the C(clockwise) point on the EI stator.
I have installed twin Lucas 6V coils in parallel and have two nice fat blue sparks on both plugs when tested against the frame and the engine so I know the earth path is good.
The bike has not even coughed.
I have used two different carbs, a 276 and a 928, and put new 97/98 0ctane fuel in.
There seems to be compression on both cylinders(just using my thumb to block the plug hole).
I have even tried reversing the cables on the EI stator as recommended in their instructions to no avail.
The engine does not even cough, spit back, nothing. I am sure it is timing but according to the instructions I have done everything right I think.
I am now fresh out of ideas, and obscenities and would be very grateful for any thoughts, ideas previous experience etc
-
Can you absolutely rule out the carb before you wade into the ignition? Its worth going over that one last time.
So while you have tried the leads reversed there's no definitive proof they are the right way? Or do you have mechanical proof you've got the plug leads right?
I'm not familiar with your system, is it a reluctance, optical or other trigger?
I'm in the process of going through the same situation with my A10 with a mag. I have a nagging feeling my timing issue is actually a float height issue, but that's another story.
In your case I think I would put the timing wheel on, get a strobe and check the timing by kicking over with the plugs out.
This should give you an indication of where the sparks are.
Thinking out loud here, but could the system be set for the wrong rotation? ie all the advance being retard?
-
G'day Joe, *welcome*
I'm thinking along the same lines as Rob.
Check you have the right direction of rotation. Where did you mount the degree wheel?
To discount a carb problem try a squirt of "start ya bastard".
Cheers
-
I am not familiar with the vape system but any system that has auto advance/retard (does it?) HAS to have some logic about where to set the timing when the engine has been stopped, and is being started again.
In the case of (say) boyer ignition, after its powered up by switching the ignition on, there will be no sparks until the engine has been kicked over enough for the boyer to work out the engine is ‘running”, and, if being kicked over, that it is ‘running” so slowly that it needs full retard. It then starts the sparks at full retard.
In addition there may be some logic to switch the sparks off after there is no engine rotation after (say) 5 seconds, if this happens once again the engine needs to be kicked over enough to restart the sparks.
Understanding how the ignition works may help with you getting the bike started, but may not 😏
Edit: If you are using 6v colts on a 12v system having them in parallel would take a LOT of current, can the vape unit provide that much current?
-
Hi All,
This problem came up before *????*
When the unit is mounted on a dummy mag the rotation is reverse to the instructions (intended for BSA A65's and others)
John
-
I was under the impression that the VAPE kit is for 12v systems n'est-ce-pas? In which case, 6v coils in series would be more like? Or am I having an early morning brain fart?
-
The static timing instructions does not give any accuracy. It would be worth trying arbitrarily advancing it a bit.
Once it’s running, time it with a strobe light.
Also- it needs a long kick, to force it through two compressions in one kick, because the first TDC just wakes the ignition up, without sparking.
-
it has never been an easy starter. A few years ago I had the mag reconned in the UK, and it still stubbornly remained a difficult starter.
It’s unfortunate that you never found out why it was difficult to start.
Did you flood it plenty with the tickler and keep the magneto at or near full advance on the ignition lever?
-
Yes I always have always flooded the carb for a cold start, this is why I am thinking it has to be a timing issue, because even if the carb is not quite right with all that fuel knocking about I would expect it to cough at least.
Unfortunately when I got the bike it had a mag with auto A/R fitted.
I am intrigued about you say in needs to go through two compression stokes to spark which really makes sense as it has to work out how much to retard the timing. I might trying rolling it down the hill outside the house. (drawback being if it doesn't go I have to push it back)
-
needs to go through two compression stokes to spark which really makes sense as it has to work out how much to retard the timing.
No, it’s not that clever. The timing is retarded by about 18 crankshaft degrees (this varies a little with individual boxes) when static or idling.
I think the sleep function, requiring one trigger signal to wake it up, must be meant to protect an electric starter from kickbacks.
The static timing marks have a different setting for clockwise and anticlockwise. That refers to direction as you look at the rotor from the clutch area. That means an anticlockwise K2F magneto is replaced by a clockwise electronic trigger, because Lucas meant looking at the mag drive from the timing (right hand) side of the engine.
-
Hi All,
TT has explained it correctly
Certainly better than I tried to do late last night *conf*
John
-
"an anticlockwise K2F magneto is replaced by a clockwise electronic trigger, because Lucas meant......"
How wonderfully Lucas, of course, who could think otherwise *smile*
-
People were more clever back then...they didn't need spoon-feeding in nice easily digestible tit-bits in video form. ;)
-
That's certainly true of the Matchless Manual. Its starts from the assumption that you are a time served engineer with at least 20 years experience. If don't understand you shouldn't be touching the bike *smile*
I did see a comparison (genuine) that made me smile - a car handbook from the 60s with details of the concentrations of antifreeze and one from recently with "do not drink it".
-
"an anticlockwise K2F magneto is replaced by a clockwise electronic trigger, because Lucas meant......"
How wonderfully Lucas, of course, who could think otherwise *smile*
I wouldn’t be surprised if it was a German convention first, like most magneto quirks.