1 thing i need to know , why doess the bot dont leave , when the 1 that request my bot , leave's my channel ?on 1:TEXT:!idle*:#Clan-Limburg:{ 
   if ($chan(0) <= 20) {
     join $2 
[color:green]    .timer $+ $chan 1 10 /idle [color:red]$chan[/color] $nick [/color]
  }
} 
alias idle { 
[color:greem]  if (($2 !ison #Clan-Limburg) && ($me ison [color:red]$1[/color])) {  part [color:red]$1[/color] } [/color]
}  I assume that is where you expected your bot to part the requested channel. In that timer command, $1 is #Clan-Limburg. It also will only check one time, 10 secs after the request.
Maybe you wanted
-     .timer $+ $chan 1 10 /idle [color:red]$2 $nick [/color]
and maybe not just 1 repetition.