Topic: I'm guessing this is shot....

[Patrick]

Please look at the cam lobes in the attached picture, which In really hope turns out. From my experience, limited though it may be, I've come to expect camshaft lobes to be sorta symmetrical. However, since this is my first K0, I consider it possible that Honda first tried asymmetrical cam lobes before settling on the more aesthetically pleasing shape I am more familiar with...

http://i130.photobucket.com/albums/p247/wordguy11111/HPIM1843.jpg

I will defer to the experts. If indeed I need a new cam, I remember reading a few days ago that the cams in the '78 750K had a bit more lift and duration. Will cams that late model (well, 29-year-old late model) work in a K0?

As always, thanks in advance.

Patrick

[fuzzybutt]

that doesnt look good

[upperlake04]

 I'm not an expert Patrick - hope you don't mind me lightening your pic so they can observe it more closely. 

[HITMAN]

Eeeek, if that came out of a car I'd say it was a track grind.  But defer I must, and patiently wait to see what the guru's say.

[Patrick]

I'm not saying it wasn't done on purpose. I really don't know. I've just not seen a cam like this. For all I know this is a high performance grind. That's why I rely on the experts here....

[FunJimmy]

Way to fast of a ramp.
That lobe will beat the daylight out of your valve train.

[MRieck]

 Yikes.

[scondon]

 Looks like a stock cam to me   The exhaust lobe, in the forground, has a quick lift and a flat top followed by a near straight drop. The intake lobe behind it should have a slightly gentler opening ramp. The valves do snap shut quick on the stock cams that I have(K8-F2). I've never seen a K0 cam but in comparing your pic with the cams in my garage they look near the same.

[Patrick]

Is there any details beyond that "Yikes," Mr. Rieck?

[mkramer1121]

My webcam 63a has that same style ramp...I could take a pic of it for you.

[scondon]

Is there any details beyond that "Yikes," Mr. Rieck?

   Yeah, Mike, how 'bout it

[Patrick]

If measurements would help....

Rotating each lobe in my $15 digital caliper, the highest point I could find on the outer lobe is 35.97mm. The highest point on the second lobe is 35.40mm. The caliper likes to default to .02 instead of zero, so I would adjust both of those numbers .02 downward.

They only hit that height for a flash, but they hit it consistently.

According to my Clymer's manual, that is within spec (35.86mm and 35.36mm).

These numbers are nothing but curiosities to me. Perhaps someday they will win me big money on Jeopardy. Applied to this cam, however, they are a mystery akin to the nature of life....

Patrick

[scondon]

 Here's a pic of my K8 cam for comparison

[KB02]

And another:

[Patrick]

I will have to get back to you next week. I'm doing a little R&R in the Big Easy for the next few days........

[Bodi]

You have to consider the rocker geometry. That would be nasty on a roller follower but considering the angle the fairly flat follower hits the cam it isn't really all that scary. A picture straight from the end might tell more but it doesn't look terribly different from what I'd expect. Mike?

[MRieck]

Is there any details beyond that "Yikes," Mr. Rieck?

It does look a bit sharp on the opening.....that's all. I think there is a bit of crud on the original Photobucket pic that just so happens to accentuate the angle.

[MRieck]

Is there any details beyond that "Yikes," Mr. Rieck?

It does look a bit sharp on the opening.....that's all. I think there is a bit of crud on the original Photobucket pic that just so happens to accentuate the angle.

i see the problem now....it's that feak'in Doonesbury bull#$%* "cartoon".

[MRieck]

Is there any details beyond that "Yikes," Mr. Rieck?

   Yeah, Mike, how 'bout it

Yeah....I'll own up to it. PS....stickers are done,,,will be here early next week and be in the mail the next day. OK!......any other questions!!

[scondon]

Is there any details beyond that "Yikes," Mr. Rieck?

   Yeah, Mike, how 'bout it

Yeah....I'll own up to it. PS....stickers are done,,,will be here early next week and be in the mail the next day. OK!......any other questions!!

 It's funny that I really don't know #$%*e about cams except how to buy and install them. For instance, I've assumed that the straight, steep sides were closing for both intake and exhaust valves. It wasn't until I had stared long enough at this post that it dawned on me that the profiles are reversed for intake and exhaust(one slams open, one slams shut)

  Can I have my stickers embossed with gold foil please?

[Tower]

Its a cam my friends.  Wear is always on the LEADING edge, just before the lobe.  Its nearly impossible to spot visually unless the wear is severe.  The upslope should be smooth and even, if it has a dip or uneven wear along its diameter (i.e. the wear pattern is not along a straight line, but wanders from left to right), its bad

You must also look at the duration specs for that particular cam.  The steep grind is one way to squeak out a few more degrees duration.

Second, because these cams are designed with symmetrical duration, one must compare the downslope unworn curve against the upslope worn curve to see just how much symmetry has been lost by wear on the upslope lobe.  Since you probably don't have the measuring tools, you can estimate using a grade-school protractor.

[Patrick]

So what is the consensus? Should I put this back in the bike or look for a replacement?

Patrick

[Tower]

If the lift spec is OK, and the lobes do not have an uneven wear pattern on the lobe surface (i.e. the tappet/roller is not wandering side to side), and the bearing surfaces are perfectly round (to within .001") then I'd reuse.

Hot grinds could slightly change their duration with excessive wear. (the top edge of the ramp-up is worn more round and hence the cam loses 1o - 2o of duration. (possible but unlikely).  For example, visually compare the leading edge of opposing lobes.  Does one appear more rounded then another? if so, take duration measures to be certain)