Greetings Gray,
I am sorry to say that these can be quite expensive pieces of kit if you want one large enough to take four inter-connected carburettors. The one we used at Stockport College was supplied by Probike, it really did clean carbs and coupled with their ASNU injector cleaning and testing unit we got superb results, but they cost a lot more than £50
There might be a motorcycle dealer in your area with the same kit, they might clean them for a modest charge.
I have a little unit from Aldi (Lakeland sell a similar item), coupled with a cleaning fluid from Maplin, and it does a good job. The problem is its small size so only one carb at a time, the time setting is small so you have to repeat and repeat and repeat the process but it is worth it. The amount of 'dirt' that comes out of the jets and drillings settling in the bottom of the tank is amazing, just looks like fine sand.
I also use a brake and clutch spray cleaner (sold by Jaguar dealers), catch the spray in a small container and leave the parts to soak. This aerosol works well with electrical switches too.
There are kits sold on eBay with 12 very thin wires or mini drills but use with extreme care and sensitivity.
Ultrasonic cleaners are amazing with fuel system items because they do not scratch the drillings.
TTFN
Hugh.