My wife is a pretty timid rider. XR100 power was enough, but XR100 size and suspension were not working. The solution, which we just got worked out after a couple tries:
G2 Ergonomics Thottle with custom cam insert--completely cut down so she can only get to about 3/4 of full throttle.
9oz Steahly flywheel weight.
Rekluse clutch (set up for slow engagement at medium RPM).
Countershaft sprocket one tooth smaller (for slow tractoring).
Richer on the pilot jet (#42 or 45).
Top clamp and riser to move bars up and foreward.
IMS tank (easier to grip and longer range).
Now, she's comfortable on the bike and it fits her properly. Remaining to be installed:
Spark arrestor end cap and quiet core insert (to reduce noise, intimidation, and sap a bit of power). I'd buy a baffled slip-on muffler if anybody made one.
Low boy footpegs (Fastway).
All in all, an expensive bike for her, but very cool!