i am have been having some problems with my bike backfing alot. so i want to check the valves because i am pretty sure that they are to tight and that is whats causing the problem. how hard is it to get to the valves to adjust them. will i need to replace any gaskets or any thing like that? and how big of an under taking will it be? If i start thur afternoon will i still be able to race sunday if every thing goes normaly?