I think it is the shape of the flywheel, it is opposite the older bikes with the rotor open side out and the stator is on the cover facing inwards. you cant just bolt a weight to it. There are replacement flywheels for other bikes with the same set up. Kawi wants alot of money for the flywheels so I thought the same money better spent on the EXP.
I just installed it the other night and it took like 20minutes. I actually had to stand around a bit while the EXP pre-soaked in some oil like they wanted in the instructions. So actual time to install is like 12-15min. It takes a couple minutes to set up the clutch free play with the bike running. I haven't been able to get out to ride it, just ran it back in forth in the shop a couple times.
I can tell you that it is going to be awsome... as long as I don't have to change clutch plates every other ride... I tried to stall it, can't do it...
I installed it with the pre installed springs for a medium engagement rpm. I was going to change it out to the low rpm engagement but it actually seems pretty good where it is. Not sure I would want a lower engagement rpm. I will have to get some seat time on it, then try all three engagement rpms some day if I have time...
The clutch pull is quite stiff now, not that it really matters anymore but non the less its pretty stiff. I think the EXP complete kit for $800 gets a lighter clutch pull, but for $400 less I will go with the heavier clutch pull as it will rarely get used.
If only they made one for the 500, its not recomended on four-strokes with a big bore kit so I think the 500 would shred it. I think I read on here they were developing one for the 500 but scrapped it because it didn't work well...
EXP auto clutch/18 inch rear trials tire/13/52 gearing--should be a good year for trail riding.

I don't think I should even need the lower gearing with the clutch but it should help the clutch last longer

mabye...