Welcome aboard.The carbs are one of the most common problems on these bikes.Not because of any design fault just age and lack of proper servicing.They are quite easy to service so long as you follow the simple steps included in the Carb section of this forum.The are four main areas to get right.
1:The slow speed circuit under the,"Black Banana" in the top section of the carbs.
2:The cleaning of the jets and emulsion tube.
3:And probably the most important the correct setting of the float heights.
4:Leaks from the Carb boots to on the engine side of the Carbs.
Under normal circumstances none of the above is very difficult for the average,"Home Mechanic" and no specialist tools are required however access to a Carb Balancer is required to fully set them up.
I use and recommend the Carbtune2,
http://www.carbtune.co.uk/carbdtls.html
This is a none mercury based Balancer,superb quality and John Morgan ships worldwide.
There web links to making your own quite cheap but I don't have them to hand.
HTH
