engine wont run

[Tumbleweed]

hello all, i removed new plug caps and wired direct to plug, removed brand new champion L82c plugs and replaced with nkg b6hs (thanks colin/ richard   )  , cleaned the mag slip ring , and kicked it twice and it was away for about 5 mins even got it almost to tick over , then my petrol feed bottle ran out of fuel so it stopped i topped it up   now it wont start again . as you say there is a solution somewhere , and im getting there, so it  dont bother me so much, thought i would mention the plugs for the record.     thanks, any more info will be welcome,           TW

[A10Boy]

I have a sneaking suspicion of your condenser. When was the mag last overhauled, do you know? If it starts and almost ticks over and only stopped cos it ran out of fuel there can be much wrong with the rest of it.

Dont worry about the springs on the AR unit, they always seem weak but the rotational forces versus friction of turning the mag always seems to close them.

[Tumbleweed]

i dont know anything about the mag it looks in good nick to me not like some ive seen , i know you cant tell just looking ive noticed there are no shims in the casing , it sparks across a 60 th gap on a plug but  not very strong ,i dont know how it should be , but it sparked ok off the bike run with a drill.   

[A10Boy]

Unfortunately, that don't mean a lot..

[Tumbleweed]

hello again, the engine started again first thing this morning, it ran for quite a while tuned it to very near tick over, then stopped it , now it will not start i have a spark at the plugs and the slip ring is cleaned so it could probably the mag as has been suggested, i think it will have to come off again, glad to hear the aa springs are probably normal  , i am nearer today than i was last week so thats got to be good

[KenF]

i dont know anything about the mag it looks in good nick to me not like some ive seen , i know you cant tell just looking ive noticed there are no shims in the casing , it sparks across a 60 th gap on a plug but  not very strong ,i dont know how it should be , but it sparked ok off the bike run with a drill.   

The Lucas slow running spec was that it should give an almost consistent spark (not more than 5% missing) across a 5.5 mm (220 thou) 3-point test gap at 130 mag rpm if it's fixed timing (or ATD), or if manual timing at 110 mag rpm advanced, and 150 mag rpm retarded.

A rough equivalent to a 5.5 mm 3-point test gap is an old plug with its earth electrode cut/ground off so that the spark has to jump the approx 4mm gap between the centre electrode and the plug body. If your mag will spark that reliably when cold and hot with a leisurely prod of the kickstart, or off the bike powered by a drill/lathe so that it's producing 4 sparks per second (a reasonably fast count of 1, 2, 3, 4, 1, 2, 3, 4 ...), your mag's probably OK. If not, it needs looking at. Could be condenser, broken HT winding, or breakdown of insulation of the windings, slip ring or pick-ups.

Best of luck,

Ken
www.brightsparkmagnetos.com

[Tumbleweed]

  thanks ken

[RichardL]

Ken,

Might/could/should demagnetization be on your list. When I intalled my EasyCap I also remagnetized. I know, not great scientific analysis practice, changing two variables, but the goal was a working mag and I definately ended up with that.  

TW,

To find a place nearby me with a magnetizer that would work, I seached for a magnet supplier, gave them a call, described the bike and they invited me over. Gent spent a good amount time helping me, no charge, just a promise to drop by on the bike so he could see it.

Richard L.

[KenF]

Sure, Richard, a weak magnet can exacerbate all sorts of other problems with a mag. But that list of things to do is aimed at what people can check while the magneto is still on the machine and without specialised equipment.

All the best,

Ken.