Just checked the compression on my newly acquired 98 kx250. read 150psi after 6 kicks. the owner said the top and bottom were done 15 hours ago. dose the compression seem too low for that amount of hours? I figured roughly -10% for 20 hours? I read the compression should be around 175-200 on a fresh rebuild. should i do the top end? what should be done to get the compression in the prime operating range?