Ranger , instead of asking for input on a particular bike shop it might have been more likely to produce useful answers if you had described why you need the services of a bike shop, and for what particular bike . - parts, tires , general tune up, major blow up ???
Guadalajara has a goodly number of small moto parts stores , brand dealerships and specialty shops for the chopper crowd, sport bikes or the utility bike sector aka "pizza bikes " of 100 to 200 cc .
If it is tires or general repairs for a gringo's touring bike you could look up that particular brand service in GDL . Or you could go to one of the general repair shops that deal with that size of bike . No point in taking an Africa Twin to a shop dealing only in Italika .Many small shops do not balance tires .
I just happened to be in GDL and in need of a rear tire in April this year and wound up getting excellent service at a business called REACMOBI .
Even though I showed up unwittingly at the hour they were preparing to close up for a 3 or 4 hour siesta they stayed open and installed and balanced a new Metzeler rear . They are a parts and general repair shop in GDL proper west of the historic center There were all sorts of bikes as customers rode in on Honda, Benelli , HD ,BMW and more brands. . You can find all about them and their location if you email your needs to
reacmobi2@hotmail.com ( or search their name and street view for an image and map location as Reacmobi ,Calle Porfirio Díaz 48, Oblatos, 44700 Guadalajara, Jal., Mexi )