Pop the helix off, take the clutch halves apart and space them with an appropriately sized bushing that fits around the secondary shaft, and is made of a softer material than the halves themselves.
Then if there is a spacer or washer or spacer between the bolt and shaft, and can thin that out to make up for the change.
Depending on how much you need to space it, it may or may not noticeable affect clutch engagement.
You can also do what bighead did on one of his fl250's
viewtopic.php?f=40&t=9952Just throwing some ideas out there. Performance use? I don't know of any reason.
-Nick