check out this link its should help.its for alto bs4 and alto k10.
if this doesnt help contact maruti on thier website and this is the response one of my friends got and it helped
Regarding the Maruti service manuals... i had asked through the maruti website and here is the below reply.
Thank you for visiting our website.
Regarding your 1st query, we wish to inform you that Service Manual is
available with all our workshops. If they do not have it, ask them to
order it through the spares department. Then you can buy it from them.
ANY TIME MARUTI
(Call- 9910202020 or Toll Free-1800 1800 180)
International Toll Free Numbers:
1866 527 5698 (From USA and Canada)
0800 0852247 (From UK)
Please Visit us at <http://www.marutiudyog.com
also in various forums it is said that the alto bs4 and alto k10 manuals are the same. im not very sure though if that's the case the link i gave you is a sure shot manual.