Is it activated by a standard mountain bike MC on the left bar where the clutch would be?
Yes, right where all rear brakes should be. I find it very easy to use and the location gives me better control over the brake.
[/quote]What made you get the XU and then upgrade rather than buying the FX?
[/quote]
For me, the low COG and being so light, makes the XU the most fun bike to ride on the street. I rode the FX for half a day up at Hollister and it was the most fun I have ever had on a dirt bike(30yrs riding). The power delivery and the belt drive gave me new perspective on how riding can be. No complaints, whatsoever. If I was going to ride more in the dirt than street, the FX would be the one to own, no question.