Well usually do not post - but here is some info for younger crowd, I am old man now but owned original H2. For your info - in 73 the early H2´s looked like the 72 (blue same strips) but had a chrome front fender. These early 73´s & the 72 were the fastest H2 produced by the Cow Factory. Later 73´s,74´s, & 75´s had different port timing & were milder than the first bikes. As for modified bikes well Denco Kawasaki in California was the last word in performance H2´s of the day. They added many changes most notably Over bored & ported with Wiseco Pistons & their own Expansion Chambers. My 73 was prepared by Denco (it cost 1.5 time the cost of the bike). This Denco H2 would pull right to pinning Tach at 12k. If I remenber it only made about 15hp or 20hp to 5000rpm then about 35 to 40 up to 7500rpm but when you hit 7500 you best be squeezing the tank, with your head hanging over gauges as you got about 65hp more INSTANTLY. It made over 110HP & with Dunlap K591´s got about 500 to 700 miles from rear tire. cruising at 110mph you could snap it down to 4th crack open the throttle & she would stand straight up, what a ride. Back in the day Ammoco Premium & KLOTZ Symthec Oil were the trick, kept the ports clean so no loss of power from carbon buildup. I was lucky & rode it for 2 yrs after the Denco Mods, then sold it. Thats why I am still here to type this. Never Ran it at the track but was never beat on the street. Ate KZ900 & 1000 for breakfast.