KZ 650 horsepower?

In the spec listings for these bikes, most models are listed at 64 HP. However the SR is listed as 60HP. How and why would they detune this models engine?

does it show differant carbs or cam timing in the specs?maybe differant exhuast?im used to the 900-1000 series bikes but its usually something easy to upgrade on differant series.

In the magazine tests back in 78 they said it was the exhaust. Being shorter and more sporty looking, meant more restriction to pass the noise and emissions standards. I think the cams are the same between the models and the carbs tuned slightly different for the SR exhaust. 1977 KZ650B ran 13.19 in the quarter, 78 KZ650SR ran 13.42. This is not a great comparison, because the 77s seemed to be the best of the 650 line performancewise, more stringent emissions meant different carb tuning in 1978 and the 1979 fresh air emissions valves on all the USA models.

the first time i saw this post i thought it was for a 650 horse kz,imagine my suprise!haha but thats allright as long as its still a kaw!

Gary Clark's KZ funnybike wasn't too far off that.