i have a 1978 xs650. i just bought it a month ago and am still kinda new to yamahas. so this is the deal. when ever i take off on the bike or when shifting to another gear it feels really boggy. i have to keep the rpms really high to shift gears and take off so it doesnt bog out. should i try syncing the carbs? clean them? rebuild them? i also bought the bike with the exhaust cut in half so there is no muffler on them. could it be bogging because there isnt enough back pressure from the exhaust? any advice or pictures or videos would be greatly appreciated