compare and contrast. sweary mick's 350 'macchi and sweary mick's 250 'macchi, the 250 has had major work done on the head, the fin's machined away to allow central spark plugging, yes, i know the principles of this, it allows a more efficient flame path and 'burn, essential to good performance, can't find any other aermacchi's with this mod, does anyone know of any? is twin plugging an option like on the boxer engines? [if we run dual coils, would this have any positive/negative effects on performance?] there's not a lot of info out there on the 'tinterweb available like there is for other machines,[and i thought mz two-stroke tuning was a dark-art!] fascinating stuff for sure and a real journey of discovery from where i'm sitting......
Don't know if you've seen these guys site. They sold two bikes to the Harley Davidson museum, a roadracer and a dirt tracker. Lot's of performance parts and other goodies. Maybe they can shed some light. Lancaster Aeramacchi Sprints...in Illinois USA. www.aeramacchisprint.com
ReplyDeleteJust my 0.02 Euros worth on twin-plugging: Basically you can both plugs on a single coil (with twin outlets), how much it'll help ? Not much I guess, because the piston's really not that big. That said it will lower the risk of detonation, when you go straight to hi-comp-land (more than 11:1) and that would also mean, you need less advance to run the engine and still get proper power from it (even more so, because a side-effect of ignition advance is, that due to the spark igniting the mix before the piston is in TDC will slow down the piston and thereby robbing you of the precious energy...
ReplyDeleteI hope I was able to (roughly) get the idea across...
Hi Greg, I'm not sure that the bike has been run with twin-plugs, rather, it's been centre plugged to get a better spark, I think that the original plug location has just been blanked off with an old plug rather than welding up the hole, Larry, I had at the Lancaster Aermacchi site, good work fella, thank's for the tip off on that one.
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