Freezeman

Jacob, Any time a valve or valves in this case do not close when they are supposed to you will have a loss of compression. In my case with this unit it now makes sense that when I first found that the intake lash was too tight on booth cylinders while checking it at TDC, The valve timing had changed some how. I originally thought it must be that the seats had receded a bit from wear and was happy that just a simple adjustment made it run again. But now it came back with the lower chain that drives booth timing chains broken.. So the intake valves not closing all the way at TDC the first time I worked on it was from that lower chain stretching a bit causing all the cams timing events to be late or retarded. Below is my attempt to post a picture of the broken chain. I now need to make or buy the "special tool" to pull the flywheel off the crank end. I hoard crap yet I can't find a 35MM 1.5 pitch nut to make my puller. https://www.facebook.com/photo.php?fbid=10215975557754824&set=a.1422066704716&type=3&eid=ARDFrorzbNPZWvb62q6P6YdhQm1uoEqedU7lHkNXVFWi_OG3Hx_s-hOTkj88wRYe0d-x776rjbyDpbga

I will try to remember to take some pics. Are the cylinders cast iron or nikasil?

Thanks for the tips. A separate shaft that turns booth cam chains... I am no longer puzzled as that has to be the heart of the problem. Tear it down.

Well this unit came back after it ran well for some time, This time it died while riding and will not restart. This time I looked back into the valve operation and to my surprise I have no rocker arm movement of either the front or rear cylinder when rotating the crank, The pistons are moving up and down, I can turn it over by hand rather easily with the spark plugs out as there is no valve spring pressure resistance because the rocker arms are not moving. I am rather puzzled... How could the two timing chains on each end of the crank running the two over head cams stop working at the same time??

Well I came on here hoping to read a manual about the quad but found that I have to make some posts before that can happen, so here is one. I work on peoples stuff. Had this well used unit come to me with a no start issue. I found it had fuel and spark was good but it only had 30 pounds of compression. I put each cylinder to TDC and feed the plug hole with a small amount of air pressure and could hear the escaping air coming out the carb openings. I then checked the valves lash at TDC and found that booth cylinders had 0 lash for the intake valves. I reset the lash to .003 for all the intake valves and reapplied a small amount of air pressure and the leaking of air was gone. I then spent a few hours screwing all the parts I had to take off, back together and then drove it out of the shop. The lash was only 1/4- 1/2 a turn too tight that caused the valve to stay open just enough to make it not start. IMO the heads could use an overhaul some time soon as the valves and seats have become a bit warn. These ATV's just have too much crap stuffed into a small space, I wounder how many fasteners are used to hold 1 ATV together? Later,