i revently had to do a valve check on my Yamaha WR400F 1999 because i noticed they were ticking. I measured everything, i have to do adjustments (the intake is tight, the exhaust is reaally loose).
So…i loosen the valve journals, take the cam out and try to pick up the bucets with the magnet but OH…IT DONT WORK. I noticed that there was a lip on the head journal that was blocking the bucket from coming out. So i watched videos on yourube of how this should be fixed and saw one that said i should etch it out with something or grind it so the bucket could move freely. I removed the lip and the buckets went out fine but the problem is that when i put the cam back in and put the cover on i noticed thar the cams dont move freely like before.
So i though “mMMhmMM…i should atleast sand it some if maybe i pushed the metal out when removing the lip”, so i took a 1200 grit and then 2000 grit and start sanding and sanding and sanding (with oil ofcourse) but noting changed, maybe a liiiiiiiittle bit of change but it wasnt even noticeable, the cam was rock hard in place (and all of this is with the cams not thightened in to the spec yet).
I started to pick out any imperfections on the journals with a razor blade but oh well…IT DONT WORK.
You can see on the videos that when the cam doesn’t have a cover on, it still has a high spot somewhere when i turn the lobes facing up. Also it gets harder to spin (almost impossible) when i press on the journal. You can see some blemishes on the journals but they are perfectly smooth to my fingernail (except those line you can see, i can feel them). The cam lobes and journals on the cam are completely smooth and do t have any grooves in them.
My question is…is the head toast or is there a fix i can do MYSELF.
r/fixxit