78 Enticer 250 clutch

[Sx Viper 700]

I have a 78 Yamaha enticer 250 that I am setting up for vintage outlaw oval racing and I was wondering what some clutch mods I could do are like maybe changing the spring? also looking for any mods that anybody wants to throw their 2 cents in on

 

[BornYamaha]

You would be way ahead if you found a way to use a later 250 motor that had the rollers & ramps. If you do I have a couple suggestions. The 78 has a different crank that won't take that clutch.