Dear jmgoujun,

as felix has already noted, this forum has lots of good information. all of the silly questions that you are asking are already answered elsewhere in the forum. you now have shown your XTR and posted unnecessary questions in numerous threads, and you definitely are NOT making friends by doing this. you are just wasting people's time.

please read our postings before asking more unnecessary questions, or posting more pictures of your bike. If you cannot read English very well, this is probably not the right forum for you. There are many good forums in Chinese.

good luck to you.