I know the heavier oil will make a big difference, and if you could fit a spring spacer in there (like PVC) it would make for a real nice ride. I have never done it on a big red, but have on a 200x, and it rides great for my larger size of 230lb compared to the stock set up.
THE 80's RAGE! Currently owns:
81, 85 Yamaha Tri Moto 125
83 Yamaha Tri Moto 200 x2
82,83 Yamaha Tri Moto 175 project
85 Yamaha Tri Z 250
84 Kawasaki Tecate 250
84 Honda ATC 70
85 Honda ATC 350X
84 Honda ATC 250R
(2) 84 Honda ATC 200x
82, 83 Honda ATC 185s
81 ATC 200
Lots of other parts and bikes