375° is not hot for a Garelli. That's actually perfect to be honest if that's all it's getting with the cast iron cylinder. The rule with a Garelli is your fine up to 420° and back off of it at 430°. I ran Swoop's rally one year in Atlanta with that same setup cruising around 440° down hill, 470°ish cruising and maxed 529° going up a big hills. No I'm not telling you to run those temps but I did and the bike still runs to this day 4yrs later with the same engine. Set the timing back where it's responsive and ride! Trust me, that kit can take 420° all day......