Yamaha had introduced reed valves to their 2 strokes a few years earlier, and Suzuki saw the marketing advantage. They probably had to jump through some patent hoops to follow suit, they came up with this blended piston port- reed valve intake system in 1976. To my mind the comparative drawing below for the straight reed intake system isn't drawn correctly, it should just have a massive passage to the used crankcase or holes in the piston skirt. Who knows if the small reed valve Suzuki used actually added much power.
1981 dad bought me two new YZ125 one as practice and back up parts bike. we had the cylinders "flow ported" as advertised in Motocross Action or suggested by knollagible sources. proper jetting and clean pipes and silencer, exacting premix measurement considerations but with whatever normal pump gas. clean asses filters, fresh lubed chain and sprockets and sharp new Pirelli or Metzeler tires, heavier front and rear and fork springs made the bikes near perfect without revalving or anything else. no other mods necessary. WINNING COMBINATION.
ReplyDeleteHeh...
ReplyDeleteFollowing on from Marshall's comment, I crewed for a guy riding an utterly stock TZ250. Stock, except for a careful rebuilding - blueprinting, essentially.
Beat a lot of riders with the zoomiest equipment.
rdguy