88 quadrunner 250 valve problem

[swampbottom]

I just bought an 88 quadrunner 250 ond it would have trouble starting sometimes. I figured the carb needed cleaning. I cleaned the carb put it back together, drained all the bad gas out of the tank and put fresh gas in it. when i tried to start it all it would do is crank and not fire off. the carb is getting gas and there is spark. tried putting gas in motor and a little in the spark plug still no firing off. i took the valve cover off and turned the motor but from as far as i can tell neither valves is moving. unsure if the valves just froze or just need adjusting. It was running when i bought it a few days ago but he sayed it was hard to start some times which makes me think it had asticking valve problem. Any help would be appreciated thanks.

[DirtDemon]

They are either stuck or bent, adjustment will help neither of those conditions. If they are bent, you will need to take the head off and replace the vavles, everything else should be replaced too, springs, seals, guides, retainers. A vavle grind should be done as well. If they are just stuck, start by removing the retainers and springs. The springs will most likely need to be replaced, and everything else should be inspected, new seals wouldn't hurt. You need to make sure the vave moves freely through the guide by spinning it around while you move it up and down, there should be no sticking or binding. This of course needs to be done while the piston is down to make room for the intruding vavle. Be very careful not to drop the valve into the cylinder. The cam and rest of the valvetrain should be checked for wear as well.