I have the 2000 gear ratio on my 99ZR 700
Black Magic twins w/ quiet cannister sounds awesome, it really not louder than stock, just throatier (if you know what I mean) sounds more like a 900 now.
Twins made this sub-par sled into a real contender. It comes off the line as good as anything out there. Most times, better!
I run 10-60 Polaris weights/ A/C orange primary, A/C green secondary and a 56/40 helix. I dont lake race, I ride trails 95% of the time and what a trail combo this is.
I agree with keeping the stock cdi in it, its faster with it that way. Carbontech reeds for me (any aftermarket reeds help, but you have to remove the cylinders to put them on) good news is that they dont cost very much. .020 timing key (may remove this though)
My airbox is modified, not gutted. I drilled 5 or 6 1&1/8 holes in the insert, removed plastic from where the air comes into the main part of the airbox( both sides) gave the foam a haircut to allow more air in and removed the coarse foam from the foot well areas where it gets its air from. does this work? Oh ya!. Now the best part of it, I keep a small roll of duct tape in the "small side" of the air box ( right side of the steering post of the airbox) When the temp drops, I tape up all the holes in the insert and it's pretty much back to stock. Back to being restrictive and more than likely a richer set-up so I dont melt down. Yes changing jets is the best way to go, but in a pinch, this works. and changing jets when its 5 below isnt fun.
I pasted this sled down to my son ( I have an 05 F7 snopro joker edition, red) But every chance I get , I still ride the old gal. Its that good/fun of a machine. He likes riding the joker anyway.
I purchased this sled new in the fall of 98. Still have it and dont plan on selling it.
Did I mention how well they handle?