Hello! My XJ 900 31a (Bj ’83) has been having a lot of problems with starting and running in cold engine lately. Until the machine is at temperature, the engine does not run round (the one or other cylinder does not ignite occasionally, engine often turns low and almost dies off), afterwards everything is great. Every time I clean the spark plugs (with the brass brush the electrodes blank brush) everything is top when driving afterwards. Jumps after 1-2 revolutions, runs also cold nice round, nothing to complain about. But already on the next day’s trip, everything is back to the old one. I changed the candles now on suspicion (replaced with original NGK BPR8ES), because they looked really rocked (the electrodes were actually not bad, distances are set of course). As to be expected with the first ride great. After that again the same problem (though perhaps not quite so bad). Now I tried the Ker by Internet search. In the appendix you can see the old candles after about an hour of highway and highway. The thread is black, the ceramic body and mass electrode are red-brown (reh-brown?) and the main electrode is outside slightly black and white and matte metallic. I have often read that deer-brown is desirable, but there are also voices that emphasize that this is no longer the case today, since these discolorations are only due to lead additives i Can you see problems with the combustion process using the candle picture? Are the discolorations normal and the problem is elsewhere? Thank you very much for any advice! Greetings Mark