Hitchcocks Forum

Hi. I have a 93 enfield that refuses to start...it originally broke down some time ago; not starting
It has new battery
it has a spark and fuel is getting to the cylinder.
I have fitted Boyer ignition
is there anything I could have missed; something to cause the spark to break down when in cylinder?
I have checked the obvious (I think) timing setup, spark (outside cyl), clean new fuel.. I get the occasional attempt/spluttering
any thoughts appreciated.

I fitted a Boyer elctronic ignition and it worked fine.. OK, I had to tune it a bit, but once I'd got it set up correctly the bike went like a rocket!

I am no electrical wizard but I followed the instructions from H's very carefully. I would suggest perhaps checking to see that you set it up at TDC?

Here are my notes, from my blog:


Link

Flying a kite or two - You have spark and fuel, good, those are the two things it needs to start, running nicely may be another matter: spluttering may be fuel mix (& check air filter?). Lack of spark in the engine, breaking down under pressure, can be spark plug tracking (often oil from dirty fingers baked onto the ceramic outside, fine black track but may not be visible, just easier to short to earth than go through the electrode): no real cure so ditch the plug and try another. Otherwise HT cap, tracking again, or faulty HT lead. Outside the engine spark should be fat and blue, red is no good.

Have you tried a new plug?
Did you fit the Boyer after breakdown, your post is a bit ambiguous on that point.
If so have you inadvertently set it up on the wrong TDC?
My BSA twin spluttered a bit when I inadvertently fitted plug leads wrong way round that makes the timing 180 degrees out

Bryan, I understand the Boyer uses an idle spark so it will spark at TDC on and off compression stroke, I hope you are recovering well and will be back on two wheels this year.

Some fuel may be getting into the cylinder but if the jets have been blocked from lack of use...

Thanks Dennis, I am getting there. Though the temptation to get out is severe I am heeding the medic & my carers who all say to wait another month or so for a bit better weather.
One result of last years unpleasantness is my brain sometimes is slow to get into gear. Like now, of course Boyer is wasted spark therefore it matters not which stroke it is timed on.
What was in my mind when I wrote that crap was when I put the leads on the Flash re-furbed magneto I got them the wrong way, kick & swing as I liked all that happened was "the occasional attempt/spluttering" as described by Gez !

Another kite idea - how old is the fuel in the tank? After a while, like a year, the petrol 'blows' and you're left with something like 75RON which might be ok in the lawnmower. Jets go gummy, petrol filter/float bowl full of sediment; try carb cleaner spray. If a halfway decent fuel mix going into the engine and you have a spark somewhere near TDC then it should at least start and run after a fashion; then get the idle mix and timing sorted.

drain carb, junk the petrol. last year I had a bantam that would not start on 6month old pre mix 2 stroke. fired 2nd kick with fresh fuel.

also, use a new plug and if all alse fails, 'easy start' is your final friend!

Don't ditch the plug because you don't get a blue spark. An orange or yellow spark often come from particles of sodium in the air ionizing in the high energy of the spark gap.
Also, laying the spark plug against the block and pulling the engine over cannot adequately test ignition coil output. When under compression, the plug requires twice the voltage to fire. Rig up something (or get a tester off Ebay) to get the spark to jump around 150thou in air. That's a much better test of your ignition system.