Camshaft Question

[jdm9123]

Does anyone know if there are any differences in the Yamaha camshafts from 77 thru 82?
Also, I am re-building my entire motor (for the second time) due to me blowing a hole in the right piston. As I removed the top end I noticed that the cams as well as the rocker arms are making a very weird pattern. I think it is due to oil loss on the top end. It's hard to describe but the cams aren't smooth anymore but rather developed sections evenly over the cam, the rocker arms also did the same thing. Looks like it's time for a top end overhaul. Lastly, has anyone opened their motor up and instead of seeing just normal oil residue, instead you see this grime/oil mud/sludge crap?? It almost seems as if all this crap from the road got into my motor. I did put on some low end pod filters and appear to have a clutch pushrod oil seal leak. Thanks in advance.

 

[XSLeo]

From 74 up all the cams have the same specs.
Can you post pics of the cam and rockers.
How long did it set before you started riding it. Setting doesn't help bikes much.
Leo

 

[CDNTX650]

i would definetly pull it right down, and also check your oil pump in the right side cover while your in there....my was scored to shit in my 78 motor, so i bought a new side cover with no scoring and cleaned up the rotors with some 2k grit, and then re clearanced the little oil pump cover back to spec.

 

[5twins]

Cam specs are the same but the '80 and newer ones will be missing the bushings for the advance rod. Mike sells them so it's easy enough to add them.

 

[jdm9123]

Here is a photo of what happened when you have a slow leak and your dipstick plays tricks on you..

it may be hard to see but there are weird worn patterns on the rocker arms and cams themselves

 

[hotdog]

hopefully that's as far as the damage has gone - you may have caught it just in time...

 

[jdm9123]

Everything else looks good still, I am going to hone the cylinders and put in new rings and pistons as well as new valve guides and valves, the bottom end looked better than the top. She will run again.

 

[scabber]

Oil and mud sludge not good or normal I would split the cases and check the crank bearings and clean out the oil passages while you have it out Better safe than sorry on that one.