Excessive cam wear

[apennine]

Hey everyone,

I just brought my new (to me) 96' Katana 600 in for a 30,000 mile service. While they were doing the valve adjustments they told me that the cam lobes themselves were in pretty bad shape. I have attached a picture of the cam.

Right now the bike runs fine. How much time can I expect to get out of these cams before they cause any problems? Also, when they do get real bad.. will the motor just violently quit one day, or will it be a slow process?

[91tana]

IMHO, that's not good. The lobes are there to open the valves open for that set duration. Take away material less duration that they are open. As to how long you will get???? Can't predict that. As for what will happen to engine when they get real bad, not sure.
I know that on the big diesel engines that I work on that cam would be junk, and I have seen them like that. Those are a different animal.

[The CyberPoet]

IMHO: that cam is junk. Don't ruin an entire engine over a couple valves and a cam by running it anyway. Search for an used cam from someone here parting out an engine or someone who has extra stuff laying around (try sending PM's to BraadaJim & to Special$K$), then also try eBay.

That's the kind of wear you get when someone pays ZERO attention to valve adjustment intervals usually -- or someone set them wrong (some of the other cams show not so great markings too), and your valve tappets or valve stems (or entire valves) may also be seriously damaged. As for the valves, they're cheap -- order new ones (cheap enough not to make sense to order used ones last time I priced them). If a valve snaps on this engine, it can take out a piston and thus the entire engine.

The fact that you're not saying it happened to a bunch of the different lobes (just this pair) means it shouldn't be a cam-chain slop issue, although I'd replace the cam-chain tensioner at the same time as the cam (or at least the spring in it).

Cheers,
=-= The CyberPoet

[Mr. Clean]

Finding a good set of used cams like those (shim & bucket style) might be kinda hard. You might consider buying a complete head off a late model Kat or Bandit 600. Special$K$ is parting out a 98+ 600 engine right now and I would bet he would give you a fair price on the head. The 98+ 600's have a 1 lobe for 2 valve set up (known ad a forked rocker) and is much more durable than the shim & bucket set up you have now. The biggest plus is it is MUCH easier to adjust the valves on the forked rocker set up.

Check this thread for Special$K$'s 2001 600 he is parting out.

http://www.katriders.com/forums/viewtopic.php?t=26120

[steves]

Actually, I have a set of those cams sitting in my garage right now. Make me an offer.

[Court93kat]

I also have a set of those cams from my 93 600 sitting in the garage.