King Cat - Need Help Please!!

I have an 04 King Cat Carbed 162 Attack 20 powder position. Last year I rode it pretty much bone stock. At that time in Colorado around Tower or Rabbit Ears it would run around 80-87 mph top end across the meadows.
This year I decided to make some changes.
1) I adjusted the power valves to 38.5mm which is what i was told they should be (previously around 42.5mm).
2) I turned the track around to hillclimb position and put on new Hiperfax slide rails and replaced both lower bearings on the drive shaft.
3) I put new rollers, pins and bushings in the factory secondary clutch.

Now I just returned from Togwotee, Wy and am having some issues with my top end speed. The thing about pulls my arms off until 40-45 mph and then just flattens out to a top end of about 50 mph. I am really confused as to why it would be so much slower than it used to be. The primary clutch is all stock as it was in Colorado, and the secondary is set the same as well.
Please, anyone have any ideas why it would be 30-40 mph slower than before?
Thanks,
Chuck

Ben,

I am the guy you chatted with. I did indeed measure from the underside of the barrel to the cable housing end with the cable snug. The main thing I cannot understand is the RPM's are running perfect in the power band (7400-7800)
Also,
I pulled the primary clutch off and am going to go through it and make sure everything is in good working order (I personally don't believe it is the primary clutch causing the problem, because I took a marker prior to riding it and there is only about a 1/4" mark on the far outside edge of the sheave left where the belt hasn't wore it off)
I was told by a Cat Rider in Tog who said I am trying to pull to steep of a Helix. It is stock (I believe 55/53). He said to try a SLP Dual Pitch Helix something like 55/45 and use a Green Sno Pro spring. Anyone else heard of this combination? If so I am willing to change Helix and Spring if anyone thinks it will help.
If I understand this right the First number is the Low Gear which will still pull as hard as it does now. The Second number is the High Gear and if it is a lower number than now it will allow the clutch shift easier and pull better on the top end.
Anyone else have other ideas?
Thanks, Chuck
Ben PM me when you get a chance. Maybe I could give you a call and we can talk more.

ttt