by Adam_Winstone » Fri Oct 05, 2018 2:10 pm
FYI - I've been suffering a similar 2-tone plug colour issue for a couple of years and have worked my way through most of the clubmans on the market, with it being impossible for me to jet/time/compression/plug grade/fuel flow this away. However, I recently changed to Ron Moss's latest offering for a 600+ mile trip to/from the 4-nations rally in Northern Ireland and wondered if this free flowing option might help, having noticed how a change in pipe would dramatically change the colour of the plug for no other changes. Having had it confirmed by Shiny Red Tuning that my bike was seriously over-jetted with the previous pipe, but knowing that it still showed hot/worryingly light at the plug (!), I wondered what the change of pipe might result in.
The new pipe did drop a little bottom end but still rode well, increasing in power through the mid range and continuing on to a higher peak RPM. However, the bike now felt rich and checking the plug at the rally showed that it had changed from light to seriously BLACK, which it should have been showing all along based on the jetting that it was running. This suggests to me that the previous pipes were 'gassing up' and cooking the plug (too hot), rather than giving a colour that reflected the jetting. I dropped the needle 1 clip for the return 300 miles and the bike ran much better, regaining much of the bottom end that I had previously lost.
BTW - Mine is a 240cc Mugello, which goes a long way to explain why mine might gas up on some clubmans, whereas I've run these pipes on other smaller cc machines without issue.
Adam