2008 KVF750 - Was Low PSI, Now No PSI After Timing
 

OK... this four wheeler came in, the guy had replaced the stator and God knows what else himself. He says it started before he did these "repairs" and now it won't. I checked compression on both cylinders and the front one was a little less than 30, the rear was right at about 50. According to the manual, the usable range of compression is supposed to be 36∼66 psi. I figured it should fire on at least the rear cylinder anyway. When I tried starter fluid, both cylinders blew fire out of the intake. I figured that somehow the valve timing had gotten off when they were doing whatever they did. I took the front rocker cover off and sure enough, the timing appeared to be off by a few teeth. I reset that as per the book (lined the flywheel up with F; ensured the arrow pointed up on the cam gear; lined both horizontal lines on the cam gear up with the surface of the head) and put everything back together. Now the front cylinder has zero compression. The valves are moving, but now the crank is harder to turn at one point than it was. Any ideas what has gone wrong with this unit?

Are you sure the timing mark agrees with TDC by the piston. I have no experience of any KVF but a lot of bikes require the flywheel off to fit a stator. If the owner didn't put the flywheel back right, the flywheel mark could be off. You may now have bent a valve by setting the cam to the flywheel instead of true TDC. 36psi sounds totally wrong for any compression reading, unless it is because a decompressor is lowering it at cranking speeds.

bent valve is what I was afraid of. I was amazed at that pressure myself. There is a compression release on the cams, so I assume that is why the PSI is said to be so low. I, too, thought that they had gotten the valve timing off when they pulled the flywheel. That was the reason that I had gone into the cam. I was under the (maybe mistaken) impression that the flywheel is (or would be) keyed to the camshaft so that it can only go on one way. I was working on the assumption that that being the case, I should be able to correct that on the valve side. The cam chain on this thing works on some wonky chain and gear transfer system.

Any quad I have come across does have a keyed flywheel, but the key is just for location, the forces are taken on the taper that locks the flywheel to the shaft, careless fitting can result in the key slipping out during fitting. Or, if the flywheel wasn't tight enough, the key shearing on start up, as the starter drives the flywheel, which then drives the crank. May not be that, but it is easy to check if the TDC mark agrees with the piston, via a light shone down a plug hole.