ive had my 66cc for a few weeks. sit seems to be running a bit sluggish recently. i had to modify the carb to manifold connection a little but it idles and seems solid with no leeks as i could tell. while riding at full throttle with the clutch engaged it doesnt scream like it used to and when i disengage the clutch and rev it out it stalls a the top of the rev.....? i started using a different fuel mixture to see if that helped. but didn't see any noticeable improvement. any thoughts?