Ignition timing with the Thorspark ignition unit

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pallijen
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Ignition timing with the Thorspark ignition unit

Post by pallijen »

Hi all,
I bought a 1953? (reg. doc. says Oct. 52) Matchless G3LS last year as a non runner. I first checked over the wiring and found that the switch had been wired into the earth side, which is not what the instructions say. Having rectified that I have followed instructions, ie. got to top dead centre, back 7/16" on compression stroke (valves closed), put a white mark on primary drive sprocket and shock absorber and fixed a wire pointer pointing to white mark. Instructions say, " you now have a white mark on the primary drive sprocket or alternator rotor, which passes a reference point when the spark should occur at full advance. Turn the engine to this point". I would like to know, what point? I haven't yet loosened the trigger unit from the end of the magneto via the central screw but am sure I will have to do so in order to adjust the timing. The bike has fired once or twice but this has really only been when it has been standing for a while, but never run. I've been off old bikes for about 30 years now so am not as clued up as I would like to be. Had problems originally with leaking fuel tank and I relined this with POR15. Also, new throttle cable from Joe Francis Motors which wasn't much good as the end just came off so had to be soldered. Had problem also where I thought the tickler was too short as the float chamber wasn't flooding but found this out to be blocked holes in the float chamber top. Any help greatly appreciated, Thanks, Paul J (Tyne and Wear)
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dave16mct
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Re: Ignition timing with the Thorspark ignition unit

Post by dave16mct »

If its been standing it might be a good idea to strip and clean out the whole carb. You can usually find instructions for electronic ignition on google or U tube.
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robcurrie
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Re: Ignition timing with the Thorspark ignition unit

Post by robcurrie »

Paul J, the timing mark is for use with a timing light, you have to rev the engine and check that the mark lines up with the pointer, so it is essential to get the engine running at least. I think the Thorspark leaflet gives an approximate initial setting to get the engine running. After fitting the Thorspark to my 650 twin the initial setting was close to correct, in fact I left it at that position because it allowed slightly more advance which I can use as my CSR has the speed kit.
Rob C
pallijen
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Location: Chesterfield UK

Re: Ignition timing with the Thorspark ignition unit

Post by pallijen »

Thanks. Stripped and cleaned carb (except for unblocking the holes in the float chamber top). Rob, regarding the ignition timing, number 10. of the instructions states; " Fit the rotor from the THORSPARK kit to the end of the magneto spindle, so that one of the magnets in it is approx. next to the marker pen on the pickup. I can't see any pen mark on the pickup. Could this have worn off or can't I see the mark once it's fitted? I suppose I could mark the outside of the magneto casing with the back plate so as I can put it back in the same position if it still doesn't work. Getting a good spark so can't see what else it could be but timing
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robcurrie
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Re: Ignition timing with the Thorspark ignition unit

Post by robcurrie »

Paul J, I am giving a link to another thread about Thorspark which has a photo which will help regarding the mark referred to.

http://www.jampot.com/forum/viewtopic.p ... rk#p157248

Rob C
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spookefoote1956
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Re: Ignition timing with the Thorspark ignition unit

Post by spookefoote1956 »

After many experiments and hair pulling out moments I read the instructions again for my thorspark. Fully advanced at TDC (Not 1/2" before), line up the big fat mark on the unit with the magnet on the rotor (to help I rigged up a bulb across the coil or use a multimeter set to continuity), bulb starts to flicker, tighten up rotor and boom, boom shake the room. I haven't bothered strobing as I reckon I get enough control out of the A/R lever. Works great now.
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
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robcurrie
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Re: Ignition timing with the Thorspark ignition unit

Post by robcurrie »

Spookefoote, did you put loctite on the screws of the Thorspark unit, mine came loose after about a year in use?
Cheers

Rob C
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spookefoote1956
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Re: Ignition timing with the Thorspark ignition unit

Post by spookefoote1956 »

No, seems alright at the moment Rob. A good point though, I may re-do with goo!
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
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