Guys and Gals, be careful!
This could be old news to those who have used the aftermarket Harley Custom type handlebar controls, but new news to us who have trundled around on Japenese and German products for years.
Thanks to a broken throttle cable, when I split the switch housing to remove the old throttle wire, I was shocked to find the chrome switch housing casting halves, where they allow the twist grip to rotate AND KEEP IT FROM PULLING OFF THE BAR were worn paper thin, even though they still had adequate lubricant. This could be catasthrophic as it would also leave you surprisingly distracted with a critical component coming loose as you are riding, and probably with a throttle jammed well above idle, regardless of return spring tension.
I suppose it is particularly more critical to all weather riders (except FREEZING), it does RAIN here in Fl. sometimes. I can only attribute the wear to that and quite a few happy miles.
My Boss is an older 97, and had roughly 16K miles on it when I purchased it. I have put approximately an additional 7,500ish milles on it here in Fl.
Shortly after I got the bike I had the infamous "brake light stuck on" phenomina, had the throttle assemble apart when I repaired that, cleaned, inspected and relubed all before I re-assembled it. I used a Dupont White Lithium and Teflon product to lube it.
I know it's a bitch to get the brake light pushbutton switch rigged carefully, and to NOT pinch the Start / kill Switch wires (been there, done that) when re-assembling the throttle side, but if your Boss, Harley, or whatever has lots of miles and years on it, you might consider checking, or having this assembly checked by a competent Mech.