Hi folks,,seen this on a couple of polinis (one a px180 and the other a t5 152) where on strip down there is some brown scorch type marks inside the crown, obviously where its got hot as one of these examples mates bike got so hot it melted the head cowling. There is no signs of it starting to hole the piston from the inside but wondered if anyone can shed some light on why it happens and is it bad and if so a solution? cheers.
any other mods you can do to make a polini 177 run cooler? retard the ignition more, bigger main? mods to head?