Ls extra powers over H???

[turbinator]

everyone says the l and h engine are the same so were does the l get its extra power does it have the same carbs?? could it just be the induction and exhaust are more free flowing???

[RedexRobB]

No idea, there are variations on cams used on the ZXR, but dont know which is related to which model. Zimm knows more about this than i do. Also the airboxes are different shapes, so could be a contributing factor?

[zimm]

airboxes differ, carbs are setup differently, cams were same until L-3 i think, with earlier ones being lumpier., ive a feeling cdi boxes got diff advance curves too but not sure. certainly, when i switched from a 1394 import cdi to a 1332 uk cdi, the bike not only benefitted from the increased rev-limit (14,900rpm over 14,500rpm) but was crisper and more eager everywhere above 12,500rpm

there are two different designs of pickup rotor (which have to be matched to the correct cdi unit), which i suspect give different amounts of static advance, increases of which zxr engines respond quite well to.

im of the opinion that the biggest difference is the airbox/carbs, the L setup giving more midrange (even more with late model cams) due to being a bit more sophisticated in terms of airbox design allowing the carbs to do their job more consistently.

the listed difference in output is only a couple of bhp, you'll get more variation than that between two runs on the same bike on different days, or different dynos, or on the same day between half a dozen identical stock bikes on the same dyno.

there's really very little in it, H's make a better noise, L's have better midrange, the different gear ratio's differ too, but ive never bothered to work out which i'd go for given a choice .. the differences are slight and 6th is the same, so theoretical top speed remains the same between the two.