sorry for delay in reply been working away thank you all for your help and will be in garage on sat go through all replies thanks again for all your help post findings soon
please can anyone help when my ty 80 gets warm it starts to missfire , running a 50-1 fuel mix new air cleaner, new main bearing to take all play out of flywheel , new points mixture screw set at 1 1/2 turns currently running on b6 ngk plug would changing to a softer plug help as the plug is all black and sooty when missfire happens thank you