Back in the early 80s many of us used to take our bikes to the old Castlereagh Dragway for the Saturday night bracket races. The king of the group was Chris Ellis on Husky Imports stock as a rock CX500 Husky which regularly ran 11.9 ETs at 106mph, going through the traps in 5th gear, another gear to go. Geoff Ballard could only pull mid 12s at 99mph on his 490 GS, Geoff Eldridge on his Finke KX500 could only low 13s. I remember beating him one time on my 81 490 GS and I gave away 20kg. My 490 ran low 13s at around 93mph and my '79 Magnum 400 ran mid 13s at 88mph. Bernie Ellis ran consistant mid 12s at 100mph on his 465 IT Yamaha, fitted with YZ top end. Those 6 speed 500 Huskys were weapons in a straight line. There were more drag racing dirt bikes but they are the ones I remember. Chris and I still have our time slips to prove it.
I recently saw a photo of a YZ450F in a drag racing magazine running a mid 12 second second run. It seems that the old 500 class bikes still have the speed over the new stuff. In the early 80s Wheelsmith sponsored a 490 Maico in California that was lowered, stretched out and raked like a pro stock bike that ran mid nines @ 130mph with nitrous.