First, please do not berate me for asking about carb tuning, I read as much as I could. Currently, I am in the freezing cold in CO (over 5600ft). The bike takes about 45 sec to warm up with choke on, then is a bit moody till completely warm. No surging in the throttle or anything. But I feel like the bike is down on power... I struggle to do even 55MPHBut that could be because of the altitude! But I noticed when I am wrapping out a gear all the way, it goes from a hum to a buzzy type of noise. Like a clacky noise. I want to say like rocks in the crankcase but it is NOT that bad!! Same noise, just verrrrry less severe. I've heard knock and ping in car engines (all V8s) and I am worried I can't hear it in an engine this small. I know engines change pitch through the RPM rang, but I'm not sure if this is the correct noise. I bought the bike from TX and it ran great there and, again, it's been fantastic here! Just I'm really worried that I need to tune the carb or rejet. When I move back to Galveston, TX (0ft, literally) I am expecting to rejet because it will be summer and 0ft... So anyways, what are the thoughts and opinions on tuning/rejetting with these conditions? Both CO and TX? I am a firm believer in tuning engines slightly rich for safety and I am very particular about doing that with an air cooled engine! Thanks so much, really loving being a TW owner and community memeber! Y'all are too awesome!