Idles with choke open but stalls on acceleration

[unfazed]

I've now bypassed the fuel filter and fired it up with the same problems. It's quite dirty so I'm going to replace it anyway but it isn't the cause of the problem. The fuel pump also appears to be working fine.

When I took the carbs off though there was some quite salty deposits around the insides of the carb rubbers.

<img src="http://foc-u.co.uk/MGalleryItem.php?id=2534" alt="" />

That is normal enough on a bike in the condition yours appears to be in the picture, clean them out with a vacuum cleaner and wipe them with WD40 which will make putting the carbs back on easier. Wipe the carb inlets the same way. To help putting them back on push back the airbox housing back as far as you can and tighten the 2 bolts. This stops the air box moving around when trying to refit the carbs

There is another inline filter where the petrol hose pipe fits on the centre carbs T piece. Be carefull removing it as the fitting between the carbs is plastic and you don't want to break it. See pic. This filter is usually forgotten, it just needs to be cleaned if it is dirty.
When cleaning the jets do not be tempted to poke steel wire through them, steel is harder then brass and can enlarge the jet, if crud needs to be dislodged use a bristle from a brass wire brush. I have found the cellulose thinners is good to clean the jets, but not for use on hands or rubber O rings. Remember to clean the emulsifier tubes also called the jet holders. On top of the emulsifier tube (jet holder) there is a seat which the needl goes through and is kept in position by the emulsifier tube( jet holder), it is a push fit, be careful it does not fall out with out you realising.