New coils for an SF2

I remember reading somewhere in my web travels in the last couple of days that a capacitor next to the coil is usually there to suprerss RF interference. I dunno whether that's true or not.

Anyway, if you have 2 capacitors in parallel, the total capacitance (in Farads) is simply the sum of the two. So you end up with more capacitance capacity. I dunno whether that's desirable or not. I guess it could change the oscillation frequency of the coil/capacitor circuit. What affect that might have on the ignition is beyond my knowledge. I think I zoned out in electronics lectures.
 
Gets more interesting. So not enough micro farads, and you burn the points. The factory race team went with double, assume it never gave problems in 24 hour racing. Can't have too much of a good thing?
 
Dual condensers ( capacitors ) are just a reliability thing, similar to aero dual ignition- you wouldn’t want to lose an endurance race for the same of a condenser that can just give up. Twin plug two strokes ( DT400etc) had similar logic but you had to swap the cap over and hope the other plug worked.
 
If you have 2 condensers on the same wire, are they both working at half their capacity? What causes them to fail? I like the idea of a solid state remote condenser, how do they work.
Do the orignal bosch condensers have paper insulation, which breaks down with age, or vynil film?

More research.......
 
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Twin plug 2-strokes usually have a hot and cold plug fitted. Hot plug for start up and warming, cold plug for full-bore. Cap swap once the engine is thoroughly warmed. Exception is the Laverda Chott, true twin-plug ignition, 2 plugs of the same type.

In my experience, condensor capacity (? ;-) ) isn't really mega-important, as long as the points arcing is supressed. Laverda also fitted doubled condensors to the racing tiddlers back in the 1950's, they realised that losing a race due to a 10-cent part simply sucks. The stock item would be fitted at the coil, the "safety" was fitted outside the points housing (not enough space inside!).

piet

laverda_chott_low_bey-31.jpg
 
Dellortoman said:
Just fit glow plugs, like a model aeroplane engine, and eliminate the entire ignition system.
Click to expand...
Been there - done that. Pulled in to the pits and switched off my Mach 3 back in the day. It carried on running at 9000rpm.
Stopped when it ran out of fuel despite all attempts to strangle it prior. And we tried - it was quite an attrraction for a few minutes.
The plating on a couple of the surface gap plugs had flaked and given me glow-plugs. Machined the plating off at home later. Borrowed a set of N54R Champions for the rest of the day.
 
When I was a kid, my dad had an old Peugeot 203 4-door saloon. Sometimes when he switched the engine off it would keep on running. He'd have to put it in gear and stall it to stop the engine. Whenever it did that he'd say it was time for a de-coke.

I seem to recall that it was quite a nice car. Somewhat more innovative and better quality than the contemporary pommy cars and offerings from Ford/Holden. It had a sun roof that was fun for us kids. I could stand on the bench seat next to the driver and stick my head out as we were travelling along. Probably wouldn't get away with that nowadays. Life was simpler back then.
 
My RT2 360 Yamaha trail bike went 'glow plug' a couple of times, once after I high sided it on a beach near Mackay and the throttle went into the sand and was stuck full open. Even after lifting it, turning everything off and removing the plug lead it continued on. It also started in reverse one day! Must have kicked back and enjoyed the timing in reverse - 5 reverse gears!
 
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