hello all new to this site and was wandering if anyone could help. The rear cylinders on my 1990 nc30 are not firing up, bought off my mate in the hope to do up and get on the road, the bike has been stood for 3 year in a dry store garage. things ive checked/done- new plugs-coils and leads fine- new battery- new reg/rec- cleaned carbs- speedo cable all the way in- side stand switch ok- if i very slowly rev the bike up it back fires and splutters till about 8000revs then runs smooth on all 4 and can get up to top revs, but otherwise runs like a dog. any help appreiciated.

sounds like carbs still clogged up, or electric fault

Check the charge rate when bike running
check your earths also

have you tryed doing a quick run down nearest long road for a clear out ?

Have you put the jets and emulsion tubes the right way around if you've been messing with the carbs?

There different front / rear...