is it really neccasary to adjust your valves on a four stroke atv becusase on a four stroke car you never adjust the valves soo why do you need to don that on an atv what makes it different?

 

I can remember adjusting lifters on my old car...it had solid lifters.
Today, nobody wants to hassle with valve adjustments , so car and truck motors have hydralic lifters. The oil in the motor is used to pump up the lifter to fill the lash, so theres no need to adjust once they are set.
Almost all ,motorcycle, and atv motors use solid lifters. They are called solid, because they cant change the length, as opposed to hydralic lifters which do.
heres an article from hotrod magazine, which explains it better.
lifters

 

if you havnt adjusted your valves yet on your raptor,,,you will most likely be very happy with the power improvements once you do

 

how diffucult is it to check and adjust

 

I will never buy a use ATV or motorcycle! Why, because there are lots of people out there who never change their oil/filter, air filters, or adjust their valves! That's about all the basic maintenance there is, and people can't even keep up on that.

I was at Pismo a couple of years ago, and the guy camped next to me had an 89 250R. He had NEVER serviced or changed the air filter, since the bike was new! The filter fell apart when he touched it. I sent him to town for a new filter. He installed it DRY, and when I offered to oil it for him, he refused saying it wasn't necessary.