512BB wrote:Well the reasons that I rarely send carburettors for rebuild are that the two bronze bushes supporting the throttle shaft are worn and non replaceable and because old carbs are very often corroded. Are they good enough reasons for you
Like I said originally - the bushes are obviously a wear item but I've yet to see a carb where the wear is to an extent where it would cause problems. Wear on mine is around 0.0007" and that's after around 180,000km. Severe corrosion will kill a carb of course. There was zero corrosion in my carbs but it had only ever run on good old fashioned leaded super Petrol before it was laid up.
To the original poster. From what I can see in the pictures the dirt and muck on your carbs is just superficial. They will clean up just fine. After a complete dismantle, removal of the throttle shafts, removal of the lower fuel gallery lead blanking plugs for cleaning access (highly recommended) followed by a clean in solvent, an ultrasonic clean and then finally a hydro-blast they will come up looking like new.
I noticed in your previous posting that you talked about putting some prongs in the two holes of the throttle shaft bearing retaining caps and twisting them out. This procedure also seems to be mentioned a lot in Youtube videos and books (non-weber issued ones that is). Don't do this. It's rubbish information. Once you have removed the spindle nuts and the throttle valves it is only necessary to tap each end of the shaft in turn with a PLASTIC hammer. This will force the bearing against the retainer and both the bearing and retainer will come out together as a unit. This is the procedure according to the factory issued Weber manual and is the correct one to use. If the bearings are corroded in you may need some heat to assist. Mine came out very easily.
Pictures of my carbs after hydro blasting attached. Note it's well worth getting yourself an ultrasonic cleaner. The Chinese ones aren't that expensive and work fine. Very useful for cleaning bits and bobs generally - not just carbs.
The tricky parts of carb rebuilding are removal and replacement of the throttle shafts and removal and replacement of the lower gallery lead plugs (these parts of the rebuild require a bit of feel and intuition). The rest is straightforward.