not a 650 but a 600 DP
600 worked flawlessly. the only reason i put this carb on was because i when to a lower elevation track and I new the 600 was just to small.
So i rebuilt the demon carb and jetted it down a little and ran it down the 1/4 at 4400 foot elevation. it ran grate. so i dropped the jets down 2 more step for our local 6600 foot 1/8 mile track and it ran grate all last season. New converter, taller tires, new SS spring out back, and the problems started.
I haven't put the 600 back on for a race, but took it around the block. still works just fine.