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Article from Gunnar Lerch, first published at “LaStrega”, the German Morini NewsWhen does it spark?or why are Morinis so sensitive with their idle motion?Perhaps one or other before has wondered himself, why, when he has to wait with his own Morini at thetraffic lights, he only can keep her running by permanent turn round at the gas handle, while the buddyon your side keeping a Moto Guzzi V35 Imola, folds his arms and simply let run his engine by it’s self?OK, Carburetor beaten out and valves are leaky , then won’t go anything, but isn't the Guzzi just as old,does her carburetor isn’t beaten out just the same way, hasn’t she the same leaky valves and one verysimilar engine concept?My answer: Most V35 have a contact ignition!Wasn’t it always said that Morinis were verymodern with their electronic ignition, and thefifties and seventies technology shall be betternow? At the selection of an igniting plant manyaspects have to be taken into account. I’mthinking about things here on the one hand likeigniting energy, trigger voltage or spark burningtime also to wear and maintenance liberty on theother hand. However. I would like to confinemyself consciously in this short article on themoment of ignition i.e. the adjustment of themoment of ignition at different revolutions perminute. In an earlier magazine Franz hasexplained in an extensive report the emergenceof an igniting altering curve with the Pickups.To this has to be added that the igniting boxeswitch are ordered under the tank also provideher contribution for the adjustmentThe altering curves of different Pickups andigniting boxes have I measured with an orderfrom an adjustable electromotor, a Pickup, anigniting box and a degree plate. At the disposal Ihad 3 red Pickups for the 3 ½ with 6 fittingigniting boxes for them as well as 2 ignitingboxes for the 500s 3 black Pickups with each 2igniting boxes for 3 ½ and 500. in addition Theseries spread of the single components undereach other turned out little relative, what surelydeclares himself from that the matching ignitingboxes are from the same motor-cycle andprobably were manufactured in the same rank.Also the igniting offset of my Pickups was inthe area of 70 to 73 degree what absolutely is totolerate . More interesting is the comparison ofthe igniting altering curves of different ignitingboxes with their accompanying Pickup.

While the igniting adjustments vary only littleat high motor speeds, 3 ½ curves are, as wellknown, 2 degrees earlier then 500s curves, arethe deviations in the engine speed range of 1000to 2000 U/min, so at the standgas immense. Ifyou compare the moment of ignition in thisrevelution range, with the static moment ofignition of an contact ignition you willconsiderable immense deviations. TheGuzzimotor is throttled down by an extremelylate moment of ignition in the standgas whilethe stopscrews of the carburetorslides arerelatively far revolved in to hold the enginerunning.The Morini would like to go higher with it’srevelution, because the early moment ofignition, so that the slide must hang very deeplyto limit the standgas revolutions. Has the slidehit out the engine pulls her mixture beside thefluttering slide, once more and once less.From diagram 1 is obvious that the alteringcurves of the ignitingboxes of newer 500sengines are just fundamentally lower in thestandgas and partial burden area than all otherboxes. In the practice I have that an engine withthese boxes allow a fundamentally stablerneutral and a driving more pleasantly in thepartial burden business.It asks the question how an optimal gatecharacteristic can look. For starting a momentof ignition surely is of advantage near the upperPoint. Here in the stand gas area, the enginemust be choked by the ignition so that a latemoment of ignition is rational like a contactignition The partial burden area should have aharmonic transition to the full throttle area torun the engine more pleasantly and more softly.At the full throttle area, the early adjustment hasto be limited, so that knocking and with thatengine troubles are avoided. As nearer you willgo to the knocking border, as higher will be theengine performance. If one exceeds her, it willgive pieces of firewood. at the next exit of afreeway. A coming down of the ignitionadjustment at high revolutions, as it is to beseen at the series ignition, , causes through theconstruction of the Pickups like Franz hasdescribed, and after my opinion, it’s only torestrict the engine performance.Furthermore a revelution limiter can protect themechanics of the engine, if at hot curves withhigh revolutions, the gear suddenly gets lost.All modern motor-cycles are equipped with aDigital ignition since these requirements on theigniting-altering-curve can be fulfilled of nocontact ignition and of electronic analogousignitions only with not acceptable effort.GunnarTranslated by Peter.(Please excuse my English, but at least I hopeyou will find this article as interesting as i foundit in German.)