I have tried one. If it is off a junior it is the same length as stock. If it is from a Senior it will be longer and raise your seat height. If it is from a 2002 or newer it is a good shock, if it's older than that they aren't as good. Also, if it's from an older air cooled model you won't have to spread your sub-frame. I weigh 230lbs. and it was too stiff for me. I have tried both newer and older types. My opinion is that it is way too stiff for the xr's swingarm ratio and like Milan (harris718) said you will lose travel. Ishock is the way to go.