So how do your like you cam shaft lobes?

I thought that I'd take a photo of this while I have it out.  I saw this over 3 years ago when we lived in NC.  I had less than 10K on the bike then.

I put it back in to see what might happen (besides, we were going to a rally, anyway)



It really has not changed much.

Looks to me like it is on the heel of the cam and if so, the valve spring pressure has dropped off at this point if the clearance is there so IMHO no reason for concern, unless the valve adjustment were to get tight. But I believe if that happened, the performance would be down to the point you would be looking into the reason. It the rocker should be floating on a good film of oil at that point. Max

What do your rocker arm pads look like? Are they pitted or flatspotted?

That build quality is certainly lacking!  Is that the stock cam that came from Suzuki?!?

bentwheel wrote on 12/31/69 at 16:00:02:


Written earlier...
Nope.  They look just fine.  Like I said, I noticed this a few K miles ago.  I had just about forgotten it until I pulled the cam last night.  It has grown only a little bit since then.

But you made me realize that I really didn't look too closely...

Well, now, I'll change my story a bit.  There is some rocker wear.  I just didn't really notice it.  I was mainly looking at the cam.

It isn't really a flat spot.  There is a contact area of wear, and the beginning and end appear to have a small groove.  You can feel it with your fingernail.  

And guess what...I can't seem to find any specs on the rocker pads in the SSM.

barry68v10 wrote on 12/31/69 at 16:00:02:


Neat eh?  Yep.  It's stock with 14K on it.

I posted it because I have never seen that on any cam.  I've seen porosity in other stock metals, but I'm really surprised with this.  I'm surprised that it made it from the grinder to QA before the engine was built.

Just cruising the forum and came across this, I used to work in a machine shop that rebuilt engines, including custom cam grinding...that cam in the pic is totally shot.
That isnt porousity, it's galling. As for the rocker pads, you may be able to get them touched up, but only at a machine shop.

The cause of the cam failure is usually lack of oil,(or to thin oil) and extreme heat.

Good input...

I did machine work for over 12 years, so I've seem galling.  I've done turning, grinding, etc. but admittedly it wasn't automotive.

Anyway, I thought that too at first.  And as much as I'd like to think that QA at Suzuki would catch such stuff, I really do think it is porosity.

Reasons are...

- I am a stickler about valve clearances.  Range is .003 -.005".  I always shoot for .004-.005" and always double check.

- Oil levels, qualities, and quantities have never been neglected or overlooked.  If nothing else, I'm one of the few that trusts Suzuki blends (THAT'S GOTTA BE IT!)

- The rocker arms have wear and flats, but no where can I find the obvious result of galling which usually means the transfer of metal material from one piece to the other.

- those are definitely pits in the cam shaft material.  Interestingly, it is on both lobes too.  Which in my thinking (warped as it is) is basically the same radial distance from center.  I think the stock camshaft material was bad.  It went to grinding, came shooting out of the CNC, got missed in inspection and ended up in my scoot.

(In my last job, QA had limits on "allowable" porosity in some of our cast materials...)

But, just on the possibility you suggest, I'll use the looser .005" adjustment when I get the new cam....especially for the bucks I'm gonna invest in it.

Thanks for your counter-point...