Very frustrating as I have just got the bike to MOT status, however had a starting problem so have taken the plugs out. Now I was aware that No. 4 was tricky to replace as the initial damage had been done by a previous owner. Now I can't get the plug back in and more than a half to one turn, so it looks like I've lost the original thread. Are there any suggestions or is it going to be a head off and an insert fix. Suggestions from the wise please.
Thanks
Greg