I converted from a magneto to a Boyer ignition with two 6 volt coils behind the oil tank on my 65 Atlas and cannot get it to start. This also has 5k resistor spark plug caps. It has been timed to TDC on the left cylinder using a dial indicator and then to 31 degrees before TDC using a degree wheel, as shown in the attached picture. Since it had not been running since last October all the gas was drained and new gas put in.
With the spark plugs out and the ignition on it sparks well using the kick starter.
Any suggestions as to what could be wrong?
Thank you in advance
Are you at 31degrees before…
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I'd look at the idle circuit…
I'd look at the idle circuit on the carb/carbs or maybe try kicking it over at larger throttle openings to take the idle circuit out of the equation. Or, spray some easy start in the intake.
Difficult to see accurately from the photo due to parallax, but that rotor looks like it's almost rubbing at the top left whereas the bottom right seems to have a big gap. The stator looks as though it could be moved upwards on its mounting plate. Have you tested the gap between stator and rotor all the way round with a feeler gauge?
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Even if the timing was…
Even if the timing was incorrectly set up with a good spark you'd get a 'pop' from the engine but indications are that you're not? With a healthy spark in evidence it sounds as if there's no fuel mixture reaching the combustion chamber!
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Firing Point
The rotor mark looks to be set-up well after TDC. Also, as Bob says, the clearance between rotor and stator looks wrong.
I think your set-up has the engine firing 30* after TDC,
You can test this by removing both plugs and marking the rotor and stator at around 30* before TDC. Then switch the ignition on with one plug earthed to the engine but easily visible from the left side. Turn the rotor with a spanner or socket until you hear or see the plug fire while observing the marks you made.
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Trying To Start The Atlas
Thank you for all your replies!
I re-checked the timing again using a dial indicator and it looks to be good. The attached picture shows the rotor pointing to TDC and the mark to the left of it is 31 degrees before TDC.
I am not entirely sure that gas is getting to the combustion chambers so I’ll take the carbs apart, clean them, reassemble, install, adjust them, and try starting it again.
There is a lesser gap near the top left of the alternator gap which will not adjust with loosening the nuts so further disassembly will be done to correct this.
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Jim, suggest if you just…
Jim, suggest if you just spray a bit of petrol in each cylinder and replace the plugs and give it a kick it should fire at least and run briefly if the timing is close. If not the timing is off and needs to be reset . The rotor stator gap maybe wrong but that is not the reason for not running. Make sure all valves have the correct clearances to ensure compression. Good luck.
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timing mark
Jim I believe your timing marks are incorrect. The mark should be where the TDC mark on the rotor points towards the wire which emerges from the stator. If you reduce a timing disc to a point where it is smaller than the stator you can transfer a mark to the stator using a white marker.
Then you will be able to strobe that mark to get the timing correct. I marked my stator 28,30.32
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I tend to agree with Andrew
Given that the Atlas and Commando engines were/are so similar and that the Lucas rotor is marked the same, then the TDC and 28-31 BTDC positions should be at about the one o'clock position (as Andrew says, where the wires exit the stator) - this where the timing inspection hole is located on the Commando primary cover. Worth double checking I would suggest.
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Which of your two marks is…
Which of your two marks on the stator is tdc? (Incidentally...the output wire is very close to the chain...)
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Boyer ignition plate
On the ignition plate for the Boyer there are two holes for timing: one for clockwise, one for anticlockwise.Have you got the right one?
See Fig.2.
(THE ATLAS ENGINE HAS THE POINTS HOUSING BEHIND THE CYLINDER
HEAD, IT’S SHAFT IS ROTATING IN THE REVERSE DIRECTION. SET TIMING ON
THE CLOCKWISE TIMING HOLE.)
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Could Be The Timing???
I have tried priming the carbs with a bit of gas, then tried priming with a bit of gas in the spark plug holes, and then also tried with the throttle 2/3 open and it still will not run at all. I am looking at what could be wrong with the timing.
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Would This Be TDC?
Please see the attached picture.
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I think its timing ,I would…
I think its timing ,I would ignore any markings on the alternator and make my own using a tdc finder down the plug hole . No more than 28 deg BTDC fully advanced with a strobe .
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Jim...picture missing..but…
Jim...picture missing..but as Rob says, marks on the rotor and stator don't mean anything. The stator is common to other machines and as far as I remember it can go on in at least three and perhaps 6 ways. And the visible bit is only resin.
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Timing Picture
Here are the timing pictures. The mark on the stator is TDC on the left cylinder using a dial indicator. The mark to the left of that is 31 degrees before TDC.
Thanks for all the replies!
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I would not trust the rotor…
I would not trust the rotor marks unless they have been checked against a piston stop tool.
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Thoughts
The thoughts about the Commando timing marks being 1-o,clock ish I concur with. Hence the rotor mark would also point 1 oclock at the timing point. Rotors should automatically be marked the same hence they would point 1 oclock. (assuming the crank key way is correct and the rotor hasn't shifted on its centre locating tube-oh yes they can!) Now the stator has been marked BUT it can be fitted in three positions SO in all cases you find TDC and use the rotor mark (or make your own) and mark the stator appropriately. Then you turn the engine forward (or backwards) to arrange for the rotor mark to come UP to the timing mark, in the direction of working. Left or right piston doesn't matter as it is electronic ignition. Ignition timing- std comp 30deg, Commando pistons 28deg
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Are you at 31degrees before t.d.c. or after t.d.c.? Timing mark on stator looks to be in the wrong spot. Stators can be wrongly marked but it might pay to recheck.