Has anyone had a go at checking valve clearances, I've got a CB600 Hornet coming up to 17000 miles and contemplating having a go myself. Not my main ride so can afford it being off road for a while so can take my time whilst learning the principles. I've got no issues with performance but can't get the carbs to stay synced and I'm wondering if excessive valve clearances are the reason, checked all the o' rings and seals for air leaks along with hoses. Any suggestions appreciated.