What it the expected top speed of a 1990 safari lx 477? I bought this thing for my wife and dad to ride along with me but God it's slow. On good packed snow I think it may hit 60mph. Could the primary not be fully engaging? the motor gets up to about 6500rmp and low end isn't bad but compared to my all of my other sleds except the SKI WIZ this is the slowest.

my little bro's old 90 Arctic cat Jag 340 fan does 80kms WOT! That is 50mph on the GPS.
My 91 Phazer II 485 fan did 120kms/hr WOT = 75mph.
If your sled is a two up, 60mph is about all you'd get out of it. they are not rockets! :)

70mph/110kmph

I had an 85 Safari 447