Possible carb problem or something else?

[Xj600s1987]

My divvy 600 was running right up until a few weeks ago.

I jumped on to go to work, and stopped at the shop about a mile down the road - running fine. Another mile and I hit a duel carraigeway, so I give it a fist full - boggs down almost immediately, so dodging the lorries and manic 6am car drivers I manage to pull over. By the time stopped she was idling nicely. So I got her home eventually - mainly at nothing more than 15 - 20 mph.

Now when I start up you can here a small muffled popping from the exhaust (missfireing), and it will not idle correctly.

If I try to ride it, it's sitting at its dodgy idle and as soon I go to pull off it boggs down. Stinks of petrol too.

When I can get going its only for a VERY short distance before I bogg down completely and cuts out. But I've realised that if I can get going and move forward some (20mph or so) and shut of letting the engine do some braking then it doesn't shut of and I can go forward another short distance.

My first thought that the carbs needed syncing so I whipped the tank off and tried to find the mixture screws and it seems that my carbs are compleatly different to the carbs described on here.

I will take some pics asap!

Any help I will appreciate very much. Cheers in advance.

Tom