Dnieper 650... This on-going project belonged to our club member Annabelle. Shed loads of work had already been done on the bike but it was still suffering from rough running. One idea to help try and tune the carburettors was to employ a Gunson's colour tune. A colour tune is a device that allows the mechanic to actually see the fuel burning in the combustion chamber. Most noteably and orange tint to the flames shows that the fuel mixture is too rich and this is what was happening in the bike's right hand cylinder when the throttle was opened with any enthusiasm. Annabelle tried raising the needle clip to lower the needle and reduce the amount of fuel that could flow past it for any given throttle opening.  However this did not appear to alter the smain symptom ,which was mainly the fact that the right hand cylinder started to intermittently misfire when the throttle was opened. Some work had already been done to try and address a poorly seated valve but the consensus...